United States Patent:

United States Patent	*5,644,363*
Mead	July 1, 1997

Apparatus for superimposing visual subliminal instructional materials on a video signal

Abstract

A subliminal video instructional device comprises circuitry for receiving an underlying video signal and presenting this signal to horizontal and vertical synchronization detection circuits, circuitry for generating a subliminal video message synchronized to the underlying video signal, and circuitry for adding the subliminal video message to the underlying video signal to create a combination video signal.

Inventors:	Mead; Talbert (Colorado Springs, CO)
Assignee:	The Advanced Learning Corp. (Colorado Springs, CO)
Appl. No.:	410275
Filed:	March 24, 1995

Current U.S. Class: 348/563; 348/473

Intern'l Class: H04N 005/445

Field of Search: 348/473,589,563,584,600,598,525,521

References Cited

U.S. Patent Documents

3278676	Oct., 1966	Becker.
3742125	Jun., 1973	Siegel	348/729.
4872054	Oct., 1989	Gray et al.	348/553.
5128765	Jul., 1992	Dingwall et al.	348/729.
5134484	Jul., 1992	Willson	348/564.
5221962	Jun., 1993	Backus et al.	348/563.
5227863	Jul., 1993	Bilbrey et al.	348/578.

Primary Examiner: Kostak; Victor R.
Attorney, Agent or Firm: Barton; Steven K.

Claims

I claim:

1. An apparatus for superimposing subliminal and non-subliminal video messages on a video signal to generate a combined video signal comprising:
a. circuitry for receiving a source video signal having horizontal and vertical synchronization information;
b. circuitry for generating sync signals by detecting said horizontal and vertical synchronization information from said video signal;
c. circuitry for generating said subliminal and non-subliminal video messages synchronized to said sync signals;
d. an analog adder for superimposing said subliminal video messages on said source video signal as received by the circuitry for receiving a source video signal, said adder further comprising a clamp circuit for superimposing said non-subliminal video messages on said source signal.

2. An apparatus for superimposing subliminal video messages on a video signal to generate a combined video signal comprising:
(a) circuitry for receiving a source video signal having horizontal and vertical synchronization information;
(b) circuitry for deriving at least one synchronization signal from said horizontal and vertical synchronization information of said video signal;
(c) a pulse width modulator for generating a pulse-width modulated signal;
(d) circuitry for generating a signal comprising said subliminal video messages synchronized to said at least one synchronization signal; and
(e) an analog adder for superimposing the subliminal video messages upon said source video signal by shifting a level of the source video signal by a subliminal signal having magnitude proportional to an integral of the pulse-width modulated signal and conveying an image of the subliminal video message signal.

3. The apparatus of claim 2 wherein during the beginning of a period in which a subliminal message is generated, a pulse width of the pulse-width modulator is ramped from a level such that the subliminal message is very weak in the combined video signal, to a level such that the subliminal message is stronger in the combined video signal.

4. The apparatus of claim 3 wherein during the end of a period in which a subliminal message is generated, a pulse width of the pulse-width modulator is ramped from a level such that the subliminal message is present in the combined video signal, to a level such that the subliminal message is weaker in the combined video signal.

Description

FIELD OF THE INVENTION

This invention relates to a system for generating subliminal instructional messages synchronized to an underlying television signal, and for superimposing these visual, and optionally aural, subliminal messages upon the underlying audiovisual television signal.

BACKGROUND OF THE INVENTION

Subliminal instructional messages are aural, symbolic, or textual messages presented with an often unrelated visual, aural, or audiovisual presentation (hereinafter the underlying video). These messages are presented in such a manner as to not be distracting to the viewer of the underlying video, which is frequently an entertainment oriented presentation. Subliminal messages are intended to be recognized by the viewer's subconscious mind, where they may eventually lead to behavioral modification.

Subliminal messages may be incorporated into a video signal for viewing on a television receiver. This may be done by substituting a frame or field of the video signal with the message, while the majority of fields or frames are those of the underlying video. Subliminal messages may also be presented by weakly modulating a visual characteristic, such as brightness, of the underlying video.

When a subliminal message is presented by weakly modulating a visual characteristic of the underlying video signal, it is important that superimposed subliminal messages be synchronized to the underlying video signal. If the superimposed message's frame and line rates differ greatly from those of the underlying video, the superimposed message may be become so broken up as to be illegible. Should the rates be closer, the message may wander, or roll, about the screen in such a way as to be distracting to the viewer.

Similarly audio subliminal messages can be superimposed upon an audio signal by mixing them with the underlying audio signal. It is, however, advantageous to increase the amplitude of the subliminal audio signal during those periods when the underlying audio signal is loud relative to the amplitude of the subliminal audio signal during those periods when the underlying audio signal is soft.

STATE OF THE ART

Systems for generating video subliminal instructional messages and superimposing them upon an underlying video signal have been described in the art. Most of these are not well suited for mass production at low cost. For example, U.S. Pat. No. 5,027,208 presents a system having a 256 by 256 "substitute frame memory" synchronously superimposed upon a video signal by means of a video mixer. While this 256.times.256 frame memory offers respectable capabilities for displaying graphic messages as well as textual messages, it also represents 8192 bytes of memory, a substantial chunk compared to the on chip memory of low cost single-chip microprocessors. The device of U.S. Pat. No. 5,027,208 also fails to provide means for on-screen programming of the device.

Similarly, U.S. Pat. No. 5,134,484 presents 18 drawing sheets detailing a method for dynamically decompressing an encoded graphical message. This message is synchronously generated and superimposed on a video signal. While the invention of U.S. Pat. No. 5,134,484 greatly reduces the required memory size for each frame, this comes at a cost of extensive logic not found on even those commercially available microprocessors which support the generating of synchronized video. Further, no provisions are made for on-screen programming or providing control over the modulation intensity of the subliminal messages. While U.S. Pat. No. 5,134,484 describes "additively" combining the subliminal signal in a "combiner," the disclosure is inadequate to determine exactly how the combining function is performed.

U.S. Pat. No. 5,221,962 describes a system that provides a manual video modulation-intensity control so that a user may consciously observe and validate the subliminal message. No on-screen programming of the subliminal message generator is described.

Many low cost control-oriented microprocessors now available include a pulse-width modulator. A pulse-width modulator comprises a few stages of latch and counter, thus inherently costs far less than the resistor-string and R-2R ladder digital to analog converters that are well known in the art. While a pulse width modulated signal may be used to communicate digital information, pulse width modulated signals are often used to drive electromechanical devices. Pulse-driven motor and lamp drivers can be of much higher efficiency than linear analog drivers, while mechanical, visual, or thermal inertia serves to integrate the mechanical impulses provided by the pulse stream.

A common prior-art approach to modulating a color video signal involves the three steps of 1) demodulating the color video signal into the three color signals Red, Green, and Blue; 2) adjusting each of the three color signals as desired; and 3) regenerating a composite video signal from the three adjusted color signals. This prior art technique is expensive in terms of the hardware required. Consider the hardware requirements of step 1 alone, the demodulating of a color signal: generally a phase-locked loop regenerates or picks off the color subcarrier; a crossover filter separates the chroma information from the luminance information; mixers combine the regenerated color subcarrier with the chroma information, producing baseband color difference signals; and finally the difference signals are combined with the luminance information to produce demodulated red, green, and blue signals.

SUMMARY OF THE INVENTION

The present invention comprises a low cost system for generating subliminal visual messages synchronized to a video signal, and superimposing those messages through a programmably variable modulation of brightness of another video signal. The subliminal messages are faded into view gradually so as to avoid distracting a viewer. The invention further comprises a combination video generation hardware that may generate both subliminal visual messages and messages associated with the on-screen programming of the system.

The stronger the modulation of a visual characteristic, or the greater the number of substituted frames, the greater the likelihood that the subliminal message will become distracting to the viewer, at which point the message ceases to be subliminal. Similarly, the weaker the modulation of the visual characteristic the less likely that the subliminal message will be perceived by the subconscious and result in a behavioral modification. It has been discovered that by fading a subliminal message onto the screen gradually, a greater degree of modulation is accepted as non-distracting to the viewer. Such a greater degree of modulation is expected to result in a greater likelihood that the viewer's subconscious will comprehend the message, and undertake a favorable behavioral modification.

The present invention also comprises a low cost method of impressing the subliminal message on the composite video signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The best mode presently contemplated for carrying out the invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a system block diagram wherein the present invention is used to superimpose a subliminal instructional message upon a video signal originating from a videotape recorder and being displayed on a television to a viewer;

FIG. 2 a block diagram of the subliminal message generator and superimposer of the present invention;

FIG. 3 a circuit diagram of the integrator, switch, scaler, and video adder of the present invention;

FIG. 4 is, a simplified block diagram of a portion of the 87C055 device used in the present preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In the presently preferred embodiment of the present invention, a videocassette recorder 10 (FIG. 1), is used to provide a source video signal 11 and a source audio signal 12. The videocassette recorder may derive this signal by playing a tape, from an antenna 13 by means of an integral tuner (not shown), from a videogame entertainment device (not shown), or from a cable television signal (not shown). The source video signal 11 and the source audio signal 12 are connected to the subliminal message generator and superimposer 14. The subliminal message generator and superimposer 14 is normally powered by a separate 12-volt D.C power supply (not shown).

An optional audio tape player 15 generates an optional second audio signal 16 which may also feed the subliminal message generator and superimposer 14. This second audio signal will be added to the source audio signal 12 to form either an audio output (not shown) or the audio component of an RF-modulated television signal output 18.

A program selection key cartridge 17 is inserted into the subliminal message generator. This key cartridge 17 contains information about the nature and sequence of the subliminal messages to be displayed; one key cartridge may contain messages such as "Quit Now--Feel Good" for smokers, another may contain messages such as "Exercise More--Feel Good" for viewers with weight problems. The subliminal message generator generates and superimposes subliminal messages upon the video signal from the VCR 10 to form either a video output (32 on FIGS. 2 and 3) or an the video component of an RF-modulated television signal output 18. The audio and video outputs, or the RF-modulated television signal 18, connect to a television receiver 19 (FIG. 1 ) or monitor (not shown) which presents both an underlying source program and the subliminal messages to a viewer (not shown).

FIG. 2 shows more detail of the subliminal message generator of the present invention. The first video input 11 connects to a synch separator 21 which extracts horizontal and vertical synchronization information from the video signal. This horizontal and vertical synchronization information is used to synchronize a video message generator 22 to the horizontal and vertical scan of the incoming video input signal 11.

The video message generator 22 data output 23 is connected to a control input of a highspeed switch 24. This switch selects either a constant 25 signal or the output of an integrator 26. When the constant 25 is selected the screen intensity of the television 20 will have a first value and when the integrator output is selected the screen intensity will have a second value dependent on the voltage output of the integrator 26. The integrator 26 output is a function of the width of a pulse-width modulated signal 29. A processor 27 drives a pulse-width modulator (PWM) 28 which produces the pulse-width modulated signal 29.

The highspeed switch 24 output is scaled by a scaler 30 and added by an adder 31 to the incoming video signal 11. The output of this adder 31 may be taken as a video output 32 for a monitor, VCR, or other device with a composite video input; or may be fed to an RF modulator 33 to generate a channel 3 or 4 television signal 18. The audio output 12 of the videocassette recorder may be attenuated by an attenuator (not shown) and mixed by a mixer 34 with an optional second audio input 16 to produce an audio output 35. This audio output 35 also serves as an audio input to the RF modulator 33, where the audio information is impressed upon the channel 3 or 4 television signal 18..

The source video signal may comply with the NTSC, SECAM, or PAL standards for composite video. While the presently contemplated initial manufactured version envisions a separately manufactured device for each of these standards, and for each language in which subliminal messages are generated, it is expected that later models of the subliminal message generator will recognize the video standard of the underlying video and automatically configure itself to the appropriate standard. Distinguishing between PAL and NTSC standards may be accomplished through timing the vertical synchronization signal extracted by the synch separator 21; as NTSC video comprises 60 fields per second while PAL comprises 50.

Revisiting the present preferred embodiment of the present invention, the pulse width modulator output 29 is available as an open-drain output of the microprocessor chip 40 (FIG. 3), where a potentiometer 41 is used to pull a logic "1" signal to a desired level. A fixed resistor may be added between this potentiometer 41 and the power supply to prevent destruction of the pulse-width modulator output 29 should the device be turned on with the wiper of potentiometer 41 turned all the way up. This pulse width modulator output is then integrated by a resistor 42 and a capacitor 43, the integral is buffered by an amplifier 44. The output of this amplifier 44 is an analog voltage that corresponds, after delays, to a digital value programmed into the pulse-width modulator 28 by the microprocessor (27 on FIG. 2)

The 87C055 video processor chip used in the presently preferred embodiment has three attribute lines on which the generated video signal 23 appears (FIG. 3), two of which are provided for non-subliminal video displays used during initialization and on-screen user programming of the system. The third of the generated video lines 23, the line on which subliminal video appears 45, is inverted and level shifted by transistor 46, resistor 47, and pull-up resistor 48. The inverted signal controls a switch comprising transistor 49 and resistor 50 which applies the buffered integral to an end of the scaling resistor 51, which feeds the summing node 52. It has been found that 10K is a suitable value for the scaling resistor 51. It has also been found that the circuit will provide an inverted but otherwise suitable superposition of the generated subliminal messages upon the underlying video signal if PNP transistor 49 is substituted with a NPN transistor, the collector-base junction of which acts as a diode to shift down (instead of the normal up) the node between resistors 50 and 51.

The video input signal 11 is buffered by an emitter-follower amplifier 53 and applied through summing resistor 54 to the summing node 52. It has been found that 511 ohms is a suitable value for the summing resistor 54. It is expected that other values may be used for the summing resistors 54 and sealing resistor 51, provided that an approximate resistance ratio of from 1 to 10 through 1 to 50 is maintained. The summed video on the summing node 52 is then buffered by an amplifier 55 to generate the video output signal 32. The operation of summing the incoming video with the switched integrator voltage effectively level shifts the underlying video signal by the subliminal message.

The non-subliminal generated video signals provided for on-screen programming enter the video switch through resistor 62 for light and resistor 56 for dark. Transistors 57 and 60, with resistors 58, 59, and 61, switch a current into summing node 52 when a dark background is desired, and transistors 63 and 66, together with resistors 62, 64, and 65 clamp the summing node 52 to a white level when a white letter or symbol is desired for on-screen programming or initialization displays. It is not necessary that the clamp circuits comprised of transistors 57, 60, 63, 66 and resistors 58, 59, 61, 62, 64, and 65 actually clamp the summing node voltage to a specific value, it is sufficient that they provide sufficient current to overwhelm the input video signal. The hardware of the present invention may be operated to provide dark letters and symbols on a white background, dark letters on an underlying video background, or white letters and symbols on an underlying video background.

The presently preferred embodiment utilizes two power supply voltages. The primary supply, known as VCC2 68, is approximately 10 volts and regulated down from a 12-volt standard wall-cube power supply. The second supply, VCC1 69, is approximately 5 volts as required for the microprocessor.

It has been found that a microprocessor with video message generator of the Phillips 83C053, 83C054, 83C055 and 87C055 family is suitable for use in the present invention. The 87C055 is preferred for prototype and low volume production, while the mask programed 83C055 is preferred for higher volume production. In the present preferred embodiment, a device of this family comprises the processor 27, the pulse-width modulator 28, and the video message generator 22 (FIG. 2). The ROM or EPROM memory of the processor contains suitable software which causes the processor 27 to perform the following functions involved in displaying a subliminal message:

a. Upon power up, the processor 27 must properly initialize the video message generator 22 for the video standard in use (NTSC or PAL are both supported by the 83C054) by the underlying video signal.

b. The system may optionally go through a welcome screen to the user to set maximum modulation levels for the subliminal messages.

c. For each message to be generated, the processor 27 sets the pulse width modulator 28 pulsewidth to zero for minimum modulation intensity.

d. The processor reads the key cartridge 17 (FIG. 2) for information regarding the message to be displayed, and formats this message in the memory of the video message generator 22. While some components of the messages are stored in the cartridge, many components such as words are stored in the ROM or EPROM memory of the processor; the cartridge need then only contain a pointer to each of these message components.

e. The pulsewidth of the pulsewidth modulator 28 is slowly increased until the desired maximum subliminal modulation level is reached. The slow increase in pulsewidth causes the message to fade into view on the television screen without distracting the viewer.

f. The message is allowed to remain on the screen for a given amount of time.

g. The pulsewidth of the pulsewidth modulator 28 is slowly decreased to zero to fade out the subliminal message.

h. Steps c through g repeat for each message to be displayed.

The video generation hardware of the 87C054/87C055 family comprises a 128 character display RAM 80 that contains a message to be displayed and four attribute bits for each character. These attribute bits determine a foreground character attribute code. These attribute codes are referred to as color codes in the 87C054/87C055 documentation. These attribute codes appear during each pixel time as a three bit binary code on the VID0, VID1, and VID2 outputs 23 (FIG. 3), of the device. The video generation hardware further comprises a character generator EPROM or ROM 81 which contains a pixel pattern for up to sixty letters and symbols that may be displayed.

In operation, a display character and foreground attribute is fetched from the display RAM 81 into a character latch 82. This character, together with a current line count within the present character row (from row counter 83), addresses a word in the character generator EPROM or ROM 81. The character generator word is placed in a parallel-load, serial output, shift register 84 and shifted each pixel time to produce a pixel signal. The pixel signal from the shift register is used to create the 3-bit attribute code output on VID0, VID1, and VID2 23 for each pixel of the generated image through selecting in a multiplexor 85 either the foreground attribute in the character latch 82 (which may be delayed 86 to compensate for the character generator cycle time) or a background attribute in a register 87. In the present preferred embodiment, a VID2-VID1-VID0 code of 111 produces unmodified underlying video, a code of 110 produces underlying video as modified for a pixel of a subliminal message, a code of 101 produces a dark pixel for non-subliminal on-screen programming use, and a code of 011 a white pixel for non-subliminal on-screen programming.

Whereas this invention is here illustrated and described with reference to embodiments thereof presently contemplated as the best mode of carrying out such invention in actual practice, it is to be understood that various changes may be made in adapting the invention to different embodiments without departing from the broader inventive concepts disclosed herein and comprehended by the claims that follow.

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United States Patent	*6,017,302*
Loos	January 25, 2000

Subliminal acoustic manipulation of nervous systems

Abstract

In human subjects, sensory resonances can be excited by subliminal atmospheric acoustic pulses that are tuned to the resonance frequency. The 1/2 Hz sensory resonance affects the autonomic nervous system and may cause relaxation, drowsiness, or sexual excitement, depending on the precise acoustic frequency near 1/2 Hz used. The effects of the 2.5 Hz resonance include slowing of certain cortical processes, sleepiness, and disorientation. For these effects to occur, the acoustic intensity must lie in a certain deeply subliminal range. Suitable apparatus consists of a portable battery-powered source of weak subaudio acoustic radiation. The method and apparatus can be used by the general public as an aid to relaxation, sleep, or sexual arousal, and clinically for the control and perhaps treatment of insomnia, tremors, epileptic seizures, and anxiety disorders. There is further application as a nonlethal weapon that can be used in law enforcement standoff situations, for causing drowsiness and disorientation in targeted subjects. It is then preferable to use venting acoustic monopoles in the form of a device that inhales and exhales air with subaudio frequency.

Inventors:	Loos; Hendricus G. (3019 Cresta Wy., Laguna Beach, CA 92651)
Appl. No.:	961907
Filed:	October 31, 1997

Current U.S. Class: 600/28

Intern'l Class: A61B 005/00

Field of Search: 600/26-28 128/897,898

References Cited

U.S. Patent Documents

4124022	Nov., 1978	Gross.
4335710	Jun., 1982	Williamson	600/28.
4573449	Mar., 1986	Warnke.
5076281	Dec., 1991	Gavish	600/28.
5123899	Jun., 1992	Gall	600/28.
5309411	May., 1994	Huang et al.	367/140.
5733240	Mar., 1998	De Visser	600/9.

Primary Examiner: Gilbert; Samuel

Claims

I claim:

1. Apparatus for manipulating the nervous system of a subject, the subject having an ear, comprising: generator means for generating voltage pulses; induction means, connected to the generator means and responsive to the voltage pulses, for inducing at the ear subliminal atmospheric acoustic pulses with a pulse frequency less than 15 Hz.

2. The apparatus according to claim 1, further comprising means for automatically controlling the voltage pulses.

3. The apparatus according to claim 1, further comprising means for monitoring the voltage pulses.

4. The apparatus according to claim 1, for exciting in the subject a sensory resonance that occurs at a resonance frequency less than 15 Hz, the apparatus further comprising tuning means for enabling a user to tune the pulse frequency to the resonance frequency.

5. The apparatus according to claim 4, further including a casing for containing the generator means, the induction means and the tuning means.

6. The apparatus according to claim 1, wherein said induction means comprise: means for generating in the atmosphere a gas jet, the latter having a momentum flux; and modulation means, connected to the generator means and responsive to said voltage pulses, for pulsing the momentum flux with a frequency less than 15 Hz; whereby subaudio acoustic pulses are induced in the atmosphere.

7. Apparatus for manipulating the nervous system of a subject, the subject having an ear, comprising: generator means for generating voltage pulses; a source of gas at a pressure different from the ambient atmospheric pressure; a conduit having an orifice open to the atmosphere for passing a gaseous flux; valve means, connected to the source of gas and the conduit to control the gaseous flux; means, connected to the generator means and responsive to said voltage pulses, for operating the valve means to provide an oscillation of the gaseous flux with a frequency less than 15 Hz.

8. The apparatus according to claim 7, further comprising vessel means for smoothing fluctuations of the gaseous flux caused by fluctuations in the pressure of the source of gas.

9. A method for manipulating the nervous system of a subject, the subject having an ear, comprising the steps of: generating voltage pulses; and inducing, in a manner responsive to the voltage pulses, at the ear subliminal atmospheric acoustic pulses with a pulse frequency less than 15 Hz.

10. The method according to claim 9, for exciting in the subject a sensory resonance that occurs at a resonance frequency less than 15 Hz, further comprising the step of tuning the pulse frequency to the resonance frequency.

11. The method according to claim 9, wherein said inducing comprises the steps of: generating in the atmosphere a gas jet, the latter having a momentum flux; and modulating the momentum flux in pulse-wise fashion in a manner responsive to the voltage pulses.

12. The method according to claim 11, further comprising the step of directing the gas jet at a material surface.

13. The method according to claim 9, wherein said inducing comprises the steps of: generating a gas flow through a conduit orifice that is open to the atmosphere; and modulating the gas flow to produce flow pulsations, in a manner responsive to the voltage pulses.

14. A method for remotely manipulating the nervous system of a subject in the course of law enforcement in a standoff situation, the subject having an ear, comprising the steps of: generating voltage pulses; generating, in a manner responsive to the voltage pulses, atmospheric acoustic signals at a plurality of locations remote from the subject for inducing at the ear subliminal atmospheric acoustic pulses with a pulse frequency less than 15 Hz, the signals having phase differences with respect to each other arranged to cause constructive acoustic wave interference at the subject.

15. A method for exciting in a subject a sensory resonance having a resonance frequency less than 15 Hz, the subject having an ear, comprising the steps of: generating voltage pulses; inducing, in a manner responsive to the voltage pulses, at the ear subliminal atmospheric acoustic pulses with a pulse frequency less than 15 Hz; tuning the pulse frequency to the resonance frequency; and also inducing audible audio-frequency atmospheric acoustic signals at the ear.

16. A method for controlling in a subject neurological disorders that involve pathological oscillatory activity of neural circuits, the subject having an ear, comprising the steps of: generating voltage pulses; inducing, in a manner responsive to the voltage pulses, at the ear subliminal atmospheric acoustic pulses with a pulse frequency less than 15 Hz; and arranging said pulse frequency to detune the pathological oscillatory activity.

17. A method for controlling in a subject epileptic seizures, the subject having an ear, comprising the steps of: generating voltage pulses; inducing in a manner responsive to the voltage pulses, at the ear subliminal atmospheric acoustic pulses with a pulse frequency less than 15 Hz; and initiating said inducing when a seizure precursor is felt by the subject.

Description

BACKGROUND OF THE INVENTION

The central nervous system can be manipulated via sensory pathways. Of interest here is a resonance method wherein periodic sensory stimulation evokes a physiological response that peaks at certain stimulus frequencies. This occurs for instance when rocking a baby, which typically provides relaxation at frequencies near 1/2 Hz. The peaking of the physiological response versus frequency suggests that one is dealing here with a resonance mechanism, wherein the periodic sensory signals evoke an excitation of oscillatory modes in certain neural circuits. The sensory pathway involved in the rocking example is the vestibular nerve. However, a similar relaxing response at much the same frequencies can be obtained by gently stroking a child's hair, or by administering weak heat pulses to the skin, as discussed in U.S. Pat. No. 5,800,481, Sep. 1, 1998. These three types of stimulation involve different sensory modalities, but the similarity in responses and effective frequencies suggests that the resonant neural circuitry is the same. Apparently, the resonance can be excited either via vestibular pathways or via cutaneous sensory pathways that carry tactile or temperature information.

Near 2.5 Hz another sensory resonance has been found that can be excited by weak heat pulses induced in the skin, as discussed in U.S. Pat. No. 5,800,481, Sep. 1, 1998. This sensory resonance brings on a slowing of certain cortical functions, as indicated by a pronounced increase in the time needed to silently count backward from 100 to 70 with the eyes closed. The effect is sharply dependent on frequency, as shown by a response peak a mere 0.13 Hz wide. The thermally excited 2.5 Hz resonance was found to also cause sleepiness, and after long exposure, dizziness and disorientation.

Other, more obscure types of stimulation in the form of weak magnetic fields or weak external electric fields can also cause the excitation of sensory resonances, as

SUMMARY OF THE INVENTION

Experiments have shown that atmospheric acoustic stimulation of deeply subliminal intensity can excite in a human subject the sensory resonances near 1/2 Hz and 2.5 Hz. The 1/2 Hz resonance is characterized by ptosis of the eyelids, relaxation, drowsiness, a tonic smile, tenseness, or sexual excitement, depending on the precise acoustic frequency near 1/2 Hz that is used. The observable effects of the 2.5 Hz resonance include a slowing of certain cortical functions, sleepiness, and, after long exposure, dizziness and disorientation. The finding that these sensory resonances can be excited by atmospheric acoustic signals of deeply subliminal intensity opens the way to an apparatus and method for acoustic manipulation of a subject's nervous system, wherein weak acoustic pulses are induced in the atmosphere at the subject's ears, and the pulse frequency is tuned to the resonance frequency of the selected sensory resonance. The method can be used by the general public for control of insomnia and anxiety, and for facilitation of relaxation and sexual arousal. Clinical use of the method includes the control and perhaps a treatment of anxiety disorders, tremors, and seizures. A suitable embodiment for these applications is a small portable battery-powered subaudio acoustic radiator which can be tuned to the resonance frequency of the selected sensory resonance.

There is an embodiment suitable for law enforcement operations in which a subject's nervous system is manipulated from a considerable distance, as in a standoff situation. Subliminal subaudio acoustic pulses at the subject's location may then be induced by acoustic waves radiating from a venting acoustic monopole, or by a pulsed air jet, especially when aimed at the subject or at another material surface, where the jet velocity fluctuations are wholly or partly converted into static pressure fluctuations.

The described physiological effects occur only if the intensity of the acoustic stimulation falls in a certain range, called the effective intensity window. This window has been measured in exploratory fashion for the 2.5 Hz resonance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a preferred embodiment wherein a modulated air jet is used for inducing subliminal acoustic pulses in the atmosphere at the subject's ears, for the purpose of manipulating the subject's nervous system.

FIG. 2 shows an embodiment in which a pulsed air jet is produced by modulating the flow from a fan by a cylindrical sheet valve that is driven by a voice coil.

FIG. 3 shows schematically an acoustic monopole operated by a solenoid valve.

FIG. 4 shows the circuit of a simple generator for producing voltage pulses that drive a piezoelectric speaker.

FIG. 5 depicts a portable battery-powered device that contains the circuit and the piezoelectric speaker of FIG. 4.

FIG. 6 shows schematically a generator for chaotic pulses.

FIG. 7 depicts a circuit for generating a complex wave.

FIG. 8 illustrates an application in a law enforcement standoff situation.

FIG. 9 contains experimental data that show excitation of the sensory resonance near 2.5 Hz, and the effective intensity window.

FIG. 10 depicts experimental data showing that the sensory excitation occurs via the ear canal.

FIG. 11 shows the buildup of the physiological response to the acoustic stimulation.

FIG. 12 shows schematically an acoustic monopole operated by a rotating valve.

DETAILED DESCRIPTION OF THE INVENTION

It has been found in our laboratory that deeply subliminal atmospheric acoustic pulses with frequency near 1/2 Hz can evoke in a human subject a nervous system response that includes ptosis of the eyelids, relaxation, drowsiness, the feeling of pressure at a centered spot on the brow, seeing moving patterns of dark purple and greenish yellow with the eyes closed, a soft warm feeling in the stomach, a tonic smile, a "knot" in the stomach, sudden loose stool, and sexual excitement, depending on the precise acoustic frequency used. These responses show that this sensory resonance involves the autonomic nervous system.

The sharp peaking of the physiological effects with frequency is suggestive of a resonance mechanism, wherein the acoustic stimulation, although subliminal, causes excitation of a resonance in certain neural circuits. Since the frequencies and responses are similar to those for the 1/2 Hz sensory resonance discussed in the Background Section, it appears that the resonance excited by the described acoustic stimulation is indeed the 1/2 Hz sensory resonance. It has been found that the 2.5 Hz sensory resonance can be excited acoustically as well. This sensory resonance causes the slowing of certain cortical processes, sleepiness, and eventually dizziness and disorientation.

One can avoid the described physiological responses by wearing snugly fitting ear plugs. This shows that the excitation occurs via the external ear canal, so that the stimulation proceeds either through the auditory nerve or the vestibular nerve. Frequencies near 1/2 Hz or 2.5 Hz are far too low for stimulating the cochlear apparatus, but they are within the response range of hair cells in the vestibular end organ. Also, there exists a low-frequency acoustic path to the vestibular end organ by virtue of the ductus reuniens which provides a fluid connection between the cochlea and the vestibular organ. The narrow duct severely attenuates acoustic signals and acts as a low pass filter with a very low cutoff frequency. Subaudio acoustic signals, i.e., acoustic signals with frequencies up to 15 Hz, may perhaps penetrate to the vestibular organ with sufficient strength for stimulating the exquisitely sensitive vestibular hair cells.

For the 1/2 Hz and 2.5 Hz resonances, the described physiological responses are observed only if the acoustic intensity lies in a certain interval, called the effective intensity window. The acoustic intensity levels in this window are far below the human auditory threshold, so that exposed subjects do not sense the acoustic pulses in any other way than through the mentioned physiological effects. The upper limit of the effective intensity window is believed to be due to nuisance-guarding neural circuitry that blocks repeditive nuisance signals from higher processing.

The acoustic signals used for the excitation of sensory resonances have the nature of pulses. The pulses may be square, trapezoid, or triangle, or rounded versions of these shapes. However, depending on the pulse frequency, strong harmonics with frequencies in the audible range could stimulate the cochlear apparatus. This may be avoided by using sine waves or appropriately rounded other waves with low harmonic content.

The acoustic pulses occur in the atmosphere air; even when administered with earphones, the pulses at the subject's ear constitute pressure and flow pulses in the local atmospheric air.

The resonance frequencies of the 1/2 Hz and 2.5 Hz sensory resonances lie respectively near 1/2 and 2.5 Hz. The different physiological effects mentioned occur at slightly different frequencies. Thus, one can tune for drowsiness or sexual excitement, as desired. The precise resonance frequency is also expected to depend slightly on the subject and the state of the nervous and endocrine systems, but it can be measured readily by tuning the acoustic pulse frequency for maximum physiological effect. Besides the resonances near 1/2 and 2.5 Hz, other sensory resonances may perhaps be found, and those with resonance frequencies below 15 Hz are expected to be excitable acoustically via the vestibular nerve, since the vestibular hair cells are sensitive in this frequency range.

The finding that deeply subliminal subaudio acoustic stimulation can influence the central nervous system suggests a method and apparatus for manipulating the nervous system of a subject by inducing subliminal atmospheric acoustic pulses of subaudio frequency at the subject's ears. In doing so, one may in addition exploit the sensory resonance mechanism, but there are important applications where this is not done. For example, the subliminal acoustic manipulation of the nervous system may be used clinically for the control of tremors and seizures, by detuning the pathological oscillatory activity of neural circuits that occurs in these disorders. This may be done by choosing an acoustic frequency that is slightly different from the frequency of the pathological oscillation. The evoked neural signals then cause phase shifts which may diminish or quench the oscillation. Exploitation of the resonance mechanism by tuning the acoustic signals to the resonance frequency of a selected sensory resonance affords other forms of manipulation, such as control of insomnia and anxiety, or facilitation of sexual arousal.

For both types of manipulation, the required subliminal subaudio acoustic pulses may be induced at one or both of the subject's ears by earphones with a proper low-frequency response, acoustic waves generated by an acoustic source and propagated through the atmosphere, or by a pulsed jet of gas (which may be air), preferably directed at a material surface open to the atmosphere, such as a wall or the subject's skin or clothing. In the area of impact, especially where the surface is oriented substantially perpendicular to the jet, atmospheric pressure pulses are then generated by virtue of the ram effect, wherein flow velocity fluctuations are wholly or partly converted into static pressure fluctuations. If the material surface on which the jet impinges includes the subject's ears, then these pressure pulses cause direct stimulation of the subject, but the pulses also propagate through the atmosphere to the subject's ears by virtue of acoustic wave propagation along accessible paths.

The induction of atmospheric acoustic pulses by a pulsed air jet proceeding in the atmosphere and directed at a subject is shown in FIG. 1, where a blower 1, labeled "FAN", produces an air jet 2 that is directed at a subject 3. The fan is powered by a power supply 4, labelled "SUPPLY". At the fan, the supply voltage is modulated in pulsed fashion by a relay 5 controlled by the generator 6, labelled "GENERATOR", through voltage pulses 7 supplied to electromagnet windings 8. A user can adjust the frequency of the pulses with the tuning control 9. The pulsing of the voltage supplied to the fan causes the momentum flux 10 of the air jet to be modulated in a pulsed manner. Upon impinging on a material surface such as the skin of the subject 3, the pulsed jet induces acoustic pressure pulses at the ears 11 of the subject. The atmospheric acoustic effect of the jet is complicated by the fact that the region of the fan inlet undergoes a fluctuation of static pressure as the result of the modulation of jet momentum flux. There thus are two distinct acoustic monopoles, one at the fan inlet and the other in the area of impact of the jet on the material surface. The monopoles radiate with a phase difference that is determined by the jet velocity, the modulation frequency, and the distance between fan and impact area. The resulting sound pressure at the subject's ears can be analyzed with retarded potentials as discussed for instance by Morse and Feshbach (1953). Even a jet which does not impinge on a material surface radiates by virtue of the acoustic monopole at the fan inlet.

When skin of the subject is exposed to gas flow of the jet, or to the flow of atmospheric air entrained by the jet, the flow will fluctuate in pulsed fashion, so that a periodic heat flux occurs by convective transport and evaporation of sweat. The resulting periodic fluctuation of the skin temperature can excite a sensory resonance, as discussed in U.S. Pat. No. 5,800,481, Sep. 1, 1998. Hence, the apparatus of FIG. 1 can cause excitation of a sensory resonance via two separate sensory pathways, viz., the vestibular nerve and the afferents from cutaneous temperature receptors. The strength of the thermal stimulation depends on the skin area and type of skin exposed to the fluctuating flow. The face is particularly sensitive, especially the lips. The two-channel excitation of sensory resonances needs further investigation. In any particular situation, the vestibular channel can be blocked by using earplugs.

An air jet with pulsed momentum flux can also be obtained as illustrated in FIG. 2. Shown is a fan 1, labelled "FAN", which discharges into manifold 12. The air flow in the manifold can be partially obstructed by a sheet valve 13 in the form of a perforated cylindrical sheet. The sheet valve carries a voice coil 14 which is situated in the field of a permanent magnet 15, in the manner of conventional electromagnetic loudspeakers. When no current flows through the voice coil, the sheet valve is held in equilibrium position by springs 16. In this position, the perforation 17 in the sheet is lined up with the flow passage allowing essentially unimpeded flow through the manifold and out the exit 18, such as to form a jet 19 in the atmosphere. Sending a current pulse through the voice coil 14 causes the sheet valve to be displayed in the axial direction, thereby partially obstructing the air flow through the manifold. Owing to the low inertia of the sheet valve, the arrangement allows efficient pulse modulation of the jet momentum flux.

A somewhat different modulation system can be obtained with a rotating cylindrical sheet valve that has one or more holes along its periphery, and which is adjacent to a stationary cylindrical shroud that has corresponding holes, so that rotation of the valve causes modulation of the air flow through the holes. The valve is rotated by a stepper motor driven by voltage pulses. The latter are obtained from a generator that is controlled by a tuner.

One can also use direct acoustic wave propagation for inducing the required atmospheric acoustic pulses. It is then advantageous to employ as the source of the waves an acoustic monopole, since for these the acoustic pressure does not fall off as fast with increasing distance as for dipoles. Moreover, at the very low frequencies involved, acoustic pressure shorting across a conventional loudspeaker baffle is very severe. A sealed loudspeaker mounted in an airtight box eliminates this pressure shorting, and radiates acoustic waves with a relatively large monopole component.

An acoustic monopole may also be produced by having a source of pressurized gas vent through an orifice into the atmosphere in a pulsed fashion. The gas may be air. Alternatively, one may have a source of low-pressure air inhale atmospheric air through an orifice in pulsed fashion. These actions are easily achieved by an oscillating or rotating valve. For purposes of discussion it is convenient to introduce the concept of gaseous flux through the orifice, defined as the integral of the normal flow velocity component over an imagined surface that tightly caps the orifice, the normal component being perpendicular to the local surface element, and reckoned positive if the flow is directed into the ambient atmosphere. The gaseous flux has the dimension of m.sup.3 /s. For the case with a source of pressurized gas, the gaseous flux is positive and due to gas venting to the atmosphere. For the case with a source of vacuum, the gaseous flux is negative and due to atmospheric air entering the orifice. The strength of the acoustic monopole is expressed as the amplitude of the gaseous flux fluctuation, amplitude being defined as half the peak-to-peak variation. The concept of gaseous flux allows a unified discussion of venting acoustic monopoles that use a source of pressurized gas or a source of vacuum, or both.

The source of pressurized air could be a cylinder with pressurized gas, such as a CO.sub.2 cartridge. For personal use, such a cartridge may last a long time because only very small acoustic monopole strengths are needed for the induction of the required weak acoustic signals. For long term and long range operation, the exhaust port of an air pump may serve as a source of pressurized air, and the intake port could be used as a source of vacuum.

A simple venting acoustic monopole is shown in FIG. 12, where the source 63 of pressurized gas, which may be air, is connected to a conduit 69 which has an orifice 65 that is open to the atmosphere. A rotating valve 66 labelled "VALVE" controls the gaseous flux through the orifice. The valve is rotated by a stepper motor 67 labelled "MOTOR", driven by voltage pulses from the generator 68 labelled "GENERATOR". The motor speed is determined by the frequency of the voltage pulses. This frequency can be selected by the tuner 70, which therefore controls the frequency of the acoustic pulses emited by the orifice 65. For the simple orifice shown, boundary layer separation may occur in the outflow, so that the air pulses emerge in the form of jets. This causes dipole and higher multipole components in the radiated acoustic field. If desired, such radiation components can be avoided or diminished by placing a spherically or dome shaped fine mesh screen over the orifice 65. Instead of holding pressurized gas, the source 63 may hold a vacuum. In either case, the pulsing of the gaseous flux causes radiation of monopole-type acoustic waves. The source 63 may be replenished by a pump.

Push-pull operation can be achieved in the manner shown in FIG. 3. An air pump 20, labelled "PUMP", with flow ports 64, pressurizes the pressure vessel 21 while drawing a vacuum in the vacuum vessel 22. A valve 23 is operated by the solenoid 24 such as to alternately admit high and low pressure air to the conduit 26. The latter vents to the atmosphere through a screen 55 placed across an orifice 27 that is open to the atmosphere. The valve is controlled by an oscillator consisting of the solenoid 24, which is connected to the pulse generator 6, labelled "GENERATOR". The frequency of the electric current pulses through the solenoid is determined by the setting of the tuning control 9. This frequency is to be tuned to the resonance frequency of the sensory resonance that is to be excited. The tuning may be done manually by a user. The conduit 26 is structured as a diffuser in order to avoid boundary layer separation during the exhaust phase; the screen across the orifice 27 inhibits formation of a jet, thereby providing more nearly for a monopole type acoustic wave. During the intake phase the orifice acts as a sink; streamlines 28 of the resulting flow are illustrated. The vessels 21 and 22 smooth the flow fluctuations through the orifice that are due to the flow fluctuations through the pump; they are drawn at a relatively small scale for compactness sake. Instead of the oscillating valve 23, a rotating valve may be used, driven by a stepper motor powered by voltage pulses from a generator.

Conventional loudspeakers may be used as well as the source of acoustic radiation. An example is shown in FIG. 4, where the piezoelectric transducer 37 is driven by a simple battery-powered pulse generator built around two RC timers 30 and 31. Timer 30 (Intersil ICM7555, for instance) is hooked up for astable operation; it produces a square wave voltage with a frequency determined by capacitor 33 and the potentiometer 32, which serves as a tuner that may be operated by a user. The square wave voltage at output 34 drives the LED 35, and appears at one of the output terminals 36, after voltage division by potentiometer 71. The other output is connected to the negative supply. The output terminals 36 are connected to the piezoelectric speaker. Automatic shutoff of the voltage that powers the timer 30 at point 38 is provided by a second timer 31, hooked up for monostable operation. Shutoff occurs after a time interval determined by resistor 39 and capacitor 40. Timer 31 is powered by a 9 Volt battery 41, via a switch 42. Optional rounding of the square wave is done by an RC circuit consisting of a resistor 43 and capacitor 44. An optional airtight enclosure 29 may be used for the speaker 37, in order to enhance the monopole component of the radiated acoustic signal. Instead of a piezoelectric speaker one may use an electromagnetic loudspeaker with a voice coil. Because of the low impedance of the voice coil, a resistor must then be included in the output circuitry in order to keep the output currents to low values such as to allow battery powering of the device. Small voice coil currents are sufficient for the low acoustic powers required.

Low pulse frequencies can be monitored with the LED 35 of FIG. 3. The LED blinks on and off with the square wave, and it doubles as a power indicator. The pulse frequency can be determined by reading a clock and counting the LED light pulses. For higher frequencies a monitoring LED can still be used, if it is driven by a signal obtained by frequency division of the generator signal.

The automatic shutoff described above is an example for automatic control of the generated voltage; more sophisticated forms of control involve automatic frequency sequences. A computer that runs a simple timing program can be used for the generation of all sorts of square waves that can be made available at a computer port. An economic and compact version of such arrangement is provided by the Basic Stamp manufactured by Parallax Inc, Rocklin, Calif., which has an onboard EEPROM that can be programmed for the automatic control of the generated pulses, such as to provide desired on/off times, frequency schedules, or chaotic waves. The square waves can be rounded by RC circuits, and further smoothed by integration and filtering.

A compact packaging of the device such as shown of FIG. 4 is depicted in FIG. 5 where all circuit parts and the speaker, piezoelectric or voice-coil type, are contained in a small casing 62. Shown are the speaker 37, labelled "SPEAKER", driven by the generator 6, labeled "GENERATOR", with tuning control 9, LED 35, battery 41, and power switch 42. The LED doubles as a mark for the tuning control dial. With the circuit of FIG. 4, the device draws so little current that it can be used for several months as a sleeping aid, with a single 9 Volt battery.

For the purpose of thwarting habituation to the stimulation, irregular features may be introduced in the pulse train, such as small short-term variations of frequency of a chaotic or stochastic nature. Such chaotic or stochastic acoustic pulses can cause excitation of a sensory resonance, provided that the average pulse frequency is close to the appropriate sensory resonance frequency. A chaotic square wave can be generated simply by cross coupling of two timers. FIG. 6 shows such a hookup, where timers 72 and 73, each labeled "TIMER", have their output pins 74 and 75 connected crosswise to each other's control voltage pins 76 and 77, via resistors 78 and 79. The control voltage pins 76 and 75 have capacitors 80 and 81 to ground. If the timers are hooked up for astable operation with slightly different frequencies, and appropriate values are chosen for the coupling resistors and capacitors, the output of either timer is a chaotic square wave with an oval attractor. Example circuit parameters are: R.sub.78 =440K.OMEGA., R.sub.79 =700K.OMEGA., C.sub.80 =4.7 .mu.F, C.sub.81 =4.7 .mu.F, with (RC).sub.72 =0.83 s and (RC).sub.73 =1.1 s. For these parameters, the output 74 of timer 72 is a chaotic square wave with a power spectrum that has large peaks at 0.46 Hz and 0.59 Hz. The resulting chaotic wave is suitable for the excitation of the 1/2 Hz resonance.

A complex wave may be used for the joint excitation of two different sensory resonances. A simple generator of a complex wave, suitable for the joint excitation of the 1/2 Hz autonomic resonance and the 2.5 Hz cortical resonance, is shown in FIG. 7. Timers 82 and 83 are arranged to produce square waves of frequencies f.sub.1 and f.sub.2 respectively, where f.sub.1 is near 2.5 Hz, and f.sub.2 is near 1/2 Hz. The outputs 84 and 85 of the timers are connected to the inputs of an AND gate 86. The output 87 of the AND gate features a square wave of frequency f.sub.1, amplitude modulated by a square wave of frequency f.sub.2, as indicated by the pulse train 88.

The very low frequency waves needed for the acoustic stimulation of the vestibular nerve may also be provided by a sound system in which weak subaudio pulses are added to audible audio program material. This may be done in the customary manner way of adding the currents from these signals at the inverting input of an operational amplifier. The amplitude of the pulses is chosen such that the strength of the resulting acoustic pulses lies in the effective intensity window. Experiments in our laboratory have shown that the presence of audible signals, such as music or speech, does not interfere with the excitation of sensory resonances.

The invention can also be implemented as a sound tape or CD ROM which contains audible audio program material together with subliminal subaudio signals. The recording can be done by mixing the audio and subaudio signals in the usual manner. In choosing the subaudio signal level, one must compensate for the poor frequency response of the recorder and the electronics, at the ultra low subaudio frequencies used.

The pathological oscillatory neural activity involved in epileptic seizures and Parkinson's disease is influenced by the chemical milieu of the neural circuitry involved. Since the excitation of a sensory resonance may cause a shift in chemical milieu, the pathological oscillatory activity may be influenced by the resonance. Therefore, the acoustic excitation discussed may be useful for control and perhaps treatment of tremors and seizures. Frequent use of such control may afford a treatment of the disorders by virtue of facilitation and classical conditioning.

In this as well as in the detuning method discussed before, an epileptic patient can switch on the acoustic stimulation upon sensing a seizure precursor.

Since the autonomic nervous system is influenced by the 1/2 sensory resonance, the acoustic excitation of the resonance may be used for the control and perhaps the treatment of anxiety disorders.

The invention can be embodied as a nonlethal weapon that remotely induces disorientation and other discomfort in targeted subjects. Large acoustic power can be obtained easily with acoustic monopoles of the type depicted in FIG. 3 or FIG. 12. If considerable distance needs to be maintained to the subject, as in a law enforcement standoff situation illustrated in FIG. 8, several monopoles can be used, and it then may become important to have phase differences between the acoustic signals of the individual monopoles arranged in such a manner as to maximize the amplitude of the resultant acoustic signal at the location 52 of the subject. Shown are four squad cars 53, each equiped with an acoustic monopole capable of generating atmospheric pulses of a frequency appropriate for the excitation of sensory resonances. The relative phases of the emitted pulses are arranged such as to compensate for differences of acoustic path lengths 54, such that the pulses arrive at the subject location 52 with substantially the same phase, resulting in constructive interference of the local acoustic waves. Such arrangement can be achieved easily by using radio signals between the monopole units, with the target distances either dialed in manually or measured automatically with a range finder. The subaudio acoustic signals can easily penetrate into a house through an open window, a chimney, or a crack under a closed door.

Some of our experiments on acoustic excitation of sensory resonances which provide a basis for the present invention will be discussed presently. Of all the responses to the excitation of the 1/2 Hz resonance, ptosis of the eyelids stands out for distinctness, ease of detection, and sensitivity. When voluntary control of the eyelids is relinquished, the eyelid position is determined by the relative activities of the sympathetic and parasympathetic nervous systems. There are two ways in which ptosis can be used as an indicator that the autonomic system is being affected. In the first, the subject simply relaxes the control over the eyelids, and makes no effort to correct for any drooping. The more sensitive second method requires the subject to first close the eyes about half way. While holding this eyelid position, the eye are rolled upward, while giving up voluntary control of the eyelids. With the eyeballs turned up, ptosis will decrease the amount of light admitted to the eyes, and with full ptosis the light is completely cut off. The second method is very sensitive because the pressure excerted on the eyeballs by partially closed eyelids increases parasympathetic activity. As a result, the eyelid position becomes somewhat labile, exhibiting a slight flutter. The labile state is sensitive to small shifts in the activities of the sympathetic and parasympathetic systems. The method works best when the subject is lying flat on the back and is facing a moderately lit blank wall of light color.

The frequency at which ptosis is at a maximum is called the ptosis frequency. This frequency depends somewhat on the state of the nervous and endocrine systems, and it initially undergoes a downward drift, rapid at first and slowing over time. The ptosis frequency can be followed in its downward drift by manual frequency tracking aimed at keeping ptosis at a maximum. At a fixed frequency, the early ptosis can be maintained in approximately steady state by turning the acoustic stimulation off as soon as the ptosis starts to decrease, after which the ptosis goes through an increase followed by a decline. The acoustic stimulation is turned back on as soon as the decline is perceived, and the cycle is repeated.

At fixed frequencies near 1/2 Hz, the ptosis cycles slowly up and down with a period ranging upward from about 3 minutes, depending on the precise acoustic frequency used. The temporal behavior of the ptosis frequency is found to depend on the acoustic pulse intensity; the drift and cycle amplitude are smaller near the low end of the effective intensity window. This suggests that the drift and the cycling of the ptosis frequency is due to chemical modulation, wherein the chemical milieu of the neural circuits involved affects the resonance frequency of these circuits, while the milieu itself is influenced by the resonance in delayed fashion. Pertinent concentrations are affected by production, diffusion, and reuptake of the substances involved. Because of the rather long characteristic time of the ptosis frequency shift, as shown for instance by the cycle period lasting 3 minutes or longer, it is suspected that diffusion plays a rate-controlling role in the process.

The resonance frequencies for the different components of the 1/2 Hz sensory resonance have been measured, using acoustic sine waves with a sound pressure of 2.times.10.sup.-9 N/m.sup.2 at the subject's left ear. Ptosis reached a steady state at a frequency of 0.545 Hz. Sexual excitement occurred at two frequencies, 0.530 Hz and 0.597 Hz, respectively below and above the steady-state ptosis frequency. For frequencies of 0.480 Hz and 0.527 Hz the subject fell asleep, whereas tenseness was experienced in the range from 0.600 to 0.617 Hz.

The resonance near 2.5 Hz may be detected as a pronounced increase in the time needed to silently count backward from 100 to 70, with the eyes closed. The counting is done with the "silent voice" which involves motor activation of the larynx appropriate to the numbers to be uttered, but without passage of air or movement of mouth muscles. The motor activation causes a feedback in the form of a visceral stress sensation in the larynx. Counting with the silent voice is different from merely thinking of the numbers, which does not produce a stress sensation, and is not a sensitive detector of the resonant state. The larynx stress feedback constitutes a visceral input into the brain and may thus influence the amplitude of the resonance. This unwanted influence is kept to a minimum by using the count sparingly in experiment runs. Since counting is a cortical process, the 2.5 Hz resonance is called a cortical sensory resonance, in distinction with the autonomic resonance that occurs near 1/2 Hz. In addition to affecting the silent counting, the 2.5 Hz resonance is expected to influence other cortical processes as well. It has also been found to have a sleep inducing effect. Very long exposures cause dizziness and disorientation. The frequency of 2.5 Hz raises concerns about kindling of epileptic seizures; therefore, the general public should not use the 2.5 Hz resonance unless this concern has been laid to rest through further experiments.

The sensitivity and numerical nature of the silent count makes it a very suitable detector of the 2.5 Hz sensory resonance. It therefore has been used for experiments of frequency response and effective intensity window. In these experiments, rounded square wave acoustic pulses were produced with a frequency that was slowly diminished by computer, and the subject's 100-70 counting time was recorded for certain frequencies. The acoustic transducer was a small loudspeaker mounted in a sealed cabinet such as to provide acoustic monopole radiation. At fixed frequency, the acoustic monopole strenght in m.sup.3 /s varies linearly with the voice coil current, with a constant of proportionality that can be calculated from measured speaker dome excursions for given currents. The sound pressure level at the entrance of the subject's nearest external ear canal can be expressed in terms of the acoustic monopole strength and the distance from the loudspeaker. For each experiment run, the sound pressure level at the entrance of the subject's external ear canal can thus be calculated from the measured amplitude of the voice coil current and the pulse frequency. Since for the subaudio frequencies the distance from the acoustic radiator to the subject's ear is much smaller than the wavelength of the sound, the near-field approximation was used in this calculation. The sound pressure level was expressed in dB relative to the reference sound pressure of 2.times.10.sup.-5 N/m.sup.2. This reference pressure is traditionally used in the context of human hearing, and it represents about the normal minimum human hearing threshold at 1.8 KHz.

FIG. 9 shows the result of experiment runs at sound pressure levels of -67, -61, -55, and -49 dB. Plotted are the subject's 100-70 counting time versus pulse frequency in a narrow range near 2.5 Hz. Resonance is evident from the sharp peak 57 in the graph for the sound pressure level of -61 dB. The graphs also reveal the effective intensity window for the stimulation, as can be seen by comparing the magnitude of the peaks for the different sound pressure levels. For increasing intensity, the magnitude of the peak first increases but then decreases, and no significant peak shows up in the graph for the largest sound pressure of -49 dB; this can be seen better from the insert 58, which shows the graphs for -67 and -49 dB in a magnified scale. It follows that the effective intensity window extends approximately from -73 to -49 dB, in terms of the sound pressure level at the entrance of the subject's external ear canal.

The physiological response to the 2.5 Hz acoustic stimulation can be avoided by wearing earplugs. FIG. 10 is a plot of the 100-70 counting time versus acoustic pulse frequency, with and without earplugs. The sound pressure level at the entrance of the subject's external ear canal was -6 dB for both runs. Without earplugs the counting time has the peak 59, but no significant peak is seen in graph 60 for the run in which the subject used earplugs. Two conclusions can be reached from these results. First, in the experiments the 2.5 Hz resonance is essentially excited acoustically rather than through the magnetic field induced by the voice coil currents in the loudspeaker. Second, it follows that the exciting sound essentially propagates via the external ear canal, instead of through the skin and bones in the area of the ears, or via cutaneous mechanoreceptors in the skin at large.

To answer the question whether the acoustic excitation of the 2.5 Hz sensory resonance occurs perhaps through the cochlear nerve, one needs to consider the human auditory threshold curve such as shown, for instance, by Thomson (1967). The curve has a minimum near 1.8 KHz where the threshold sound pressure level is 0 dB, by definition. At 10 Hz the threshold is 105 dB. Hence, the pronounced acoustic excitation of the sensory resonance shown in FIG. 9 for a sound pressure level of -61 dB is 166 dB below the auditory threshold at 10 Hz. The excitation occurs near 2.5 Hz, and at that frequency, the auditory threshold is even higher than at 10 Hz. Although the curve in Thomson's book does not go below 10 Hz, linear extrapolation suggests the estimate of 135 dB for the threshold at 2.5 Hz, bringing the sound pressure level that is effective for acoustic excitation of the sensory resonance to 196 dB below the estimated threshold at the frequency near 2.5 Hz used. This result all but rules out excitation via the cochlear nerve.

Chemical modulation may be the cause for the small frequency difference for peaks 57 and 59 in FIGS. 9 and 10, for the sound pressure level of -61 dB; these peaks occur respectively at 2.516 and 2.553 Hz.

The physiological response to the excitation of the sensory resonances at a fixed stimulus frequency is not immediate but builds over time. An example is shown in FIG. 11, where the graph 61 depicts the measured 100-70 time plotted versus elapsed time, upon application of acoustic pulses of 2.558 Hz frequency and a sound pressure level of -61 dB. The graph shows that the response is initially delayed over about 5 minutes; thereafter it increases, and at about 22 minutes the slope is seen to decrease somewhat. Other experiments have shown a counting time that eventually settles on a plateau, or even starts on a decline. Chemical modulation and habituation could account for these features. The response curve depends strongly on initial conditions.

The method is expected to be effective also on certain animals, and applications to animal control are therefore envisioned. The nervous system of mammals is similar to that of humans, so that the sensory resonances are expected to exist, albeit with different frequencies. Accordingly, in the present invention subjects are mammals.

The described method and apparatus can be used beneficially by the general public and in clinical work. Unfortunately however, there is the possibility of mischievous use as well. For instance, with small modifications the method of FIG. 1 can be employed to imperceptibly modulate the air flow in air conditioning or heating systems that serve a home, office building, or embassy, for covert manipulation of the nervous systems of occupants.

The invention is not limited by the embodiments shown in the drawings and described in the specification, which are given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

REFERENCES

P. M. Morse and H. Feshbach, METHODS OF THEORETICAL PHYSICS, McGraw-Hill, New York, 1953

R. F. Thomson, FOUNDATIONS OF PHYSIOLOGICAL PSYCHOLOGY, Harper & Row, New York 1967

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United States Patent	*6,122,322*
Jandel	September 19, 2000

Subliminal message protection

Abstract

The present invention relates to a method and to a system for detecting a first context change between two frames. When a second context change between a further two frames occurs within a predetermined time interval, the frames accommodated within the two context changes are defined as a subliminal message. An alarm is sent to an observer upon detection of a subliminal message.

Inventors:	Jandel; Magnus (Upplands Vasby, SE)
Assignee:	Telefonaktiebolaget LM Ericsson (Stockholm, SE)
Appl. No.:	310739
Filed:	May 13, 1999

Foreign Application Priority Data

Nov 19, 1996[SE]

9604241

Current U.S. Class: 375/240.13; 348/154; 348/473; 348/699; 358/908

Intern'l Class: H04N 005/14; H04N 009/64

Field of Search: 346/46,94 358/908 348/699,700,473,475,553,154,155

References Cited

U.S. Patent Documents

5099322	Mar., 1992	Gove	358/105.
5642174	Jun., 1997	Kazui et al.	348/700.
5644363	Jul., 1997	Mead	348/563.
5719643	Feb., 1998	Nakajima	348/700.
5751378	May., 1998	Chen et al.	348/700.
5801765	Sep., 1999	Gotoh et al.	348/155.
5929920	Oct., 1999	Sizer, II	348/473.
5969755	Oct., 1999	Courtney	348/155.
Foreign Patent Documents
4106246 C1	Mar., 1992	DE.
95/06985 A1	Mar., 1995	WO.

Primary Examiner: Britton; Howard
Assistant Examiner: Diep; Nhon T
Attorney, Agent or Firm: Nixon & Vanderhye, PC

Parent Case Text

This is a continuation of PCT application Ser. No. PCT/SE97/01909, filed Nov. 13, 1997.

Claims

What is claimed is:

1. A method of distinguishing between messages in a sequence of frames that include image information, the method comprising: detecting a first context change between a first and a second frame, detecting a second context change between a third and a fourth frame, comparing the time period between the first and the second context changes with a first threshold value, and indicating said message in dependence on said comparison.

2. A method according to claim 1, characterized in that relevant data related to the first and second context changes and data relating to the source of the frame sequence are stored in a memory.

3. A method according to claim 1, characterized in that a second message is indicated in dependence on whether a third context change between said first and said fourth frame is detected.

4. A method according to claim 1, characterized in that said first context change is detected by measuring the energy difference between said first and said second frames.

5. A method according to claim 1, characterized in that said second context change is detected by measuring the energy difference between said second and said third frames.

6. A method according to claim 4, characterized in that the energy is measured by calculating, for each frame point, the difference between the value of a frame point in a first frame and the value of the corresponding frame point in a second frame, calculating the square of the calculated difference, and forming the sum of the calculated square values for all frame points.

7. A method according to claim 1, characterized in that said first context change is detected by measuring the energy in a first displaced frame difference (DFD), and using the measured energy to calculate the second frame from the first frame.

8. A method according to claim 1, characterized in that said second context change is detected by measuring the energy in a second displaced frame difference (DFD), and using the measured energy to calculate the fourth frame from the third frame.

9. A method according to claim 7, characterized by comparing the energy in the displaced frame difference with a second threshold value, and indicating a context change in dependence on said comparison.

10. A method according to claim 8, characterized by comparing the energy in the displaced frame difference with a second threshold value, and indicating a context change in dependence on said comparison.

11. A method according to claim 7, characterized in that the energy in the displaced frame difference (DFD) is measured by calculating the square of the value in each frame point in the displaced frame difference and forming the sum of the calculated values for all frame points.

12. A method according to claim 7, characterized in that the energy in the displaced frame difference (DFD) is measured by calculating the absolute magnitude of the value in each frame point in the displaced frame difference and forming the sum of the calculated values for all frame points.

13. A method according to claim 1, characterized in that the first context change is indicated when an I-frame in an MPEG-stream is detected.

14. A method according to claim 1, characterized in that the second context change is indicated when an I-frame in an MPEG-stream is detected.

15. A method according to claim 1, characterized by comparing the second frame with a fifth frame stored in a frame library, and indicating the first message in dependence on said comparison.

16. A method according to claim 2, characterized by storing in said memory the frame sequence between the first and the second context change.

17. A method according to claim 2, characterized in that a user is able to examine the contents of said memory.

18. A method according to claim 1, characterized in that said second frame and said third frame are one and the same frame.

19. A system for automatically detecting subliminal messages in a frame sequence, the system comprising: means for measuring context changes between two frames in the frame sequence; means for initiating an alarm; means for storing a frame sequence; means for calculating a time difference between two context changes; means for comparing a measured time difference with a threshold value; and means for initiating an alarm in response to the outcome of said means for comparing.

Description

The present invention relates to a system and to a method for protecting an observer from subliminal messages.

BACKGROUND OF THE INVENTION

Subliminal messages are messages that are sent in a manner such as to be undetectable consciously by an observer. Subliminal messages are hidden suggestions that can only be perceived by the subconscious. In video communication, a subliminal message can be flashed so quickly that the viewer will not be aware of having seen the message. The viewer can, nevertheless, be influenced by the message content. Consider, for instance, the case of a subliminal advertisement that is sent while the viewer is studying the latest televised news from the stock market. The advertisement may inform the viewer that ACME chocolate is good to eat, but is flashed so quickly that the viewer is unaware that he/she has been subjected to an advertisement. Some viewers, however, can be influenced subconsciously by the advertisement, and later feel an unexplainable longing for ACME chocolate.

The ground-based transmission of television channels are subject to ethical and legal constraints that are aimed towards preventing the above type of advertising. However, it is not possible to guarantee the prevention of the transmission of subliminal messages in many of the international satellite-based television channels that do not obey local laws and regulations. The protection of an observer from such messages is more difficult to achieve in modern types of communications, such as Internet and videotelephony, for instance. Subliminal messages can be hidden not only in a video sequence, but also in still images, or what the observer considers to be still images, and also in audio sequences.

Two mutually sequential images of an image sequence are seldom exactly the same. The fundamental concept of mediating movement with the aid of a plurality of mutually sequential images is that each image will differ slightly from the preceding image. When the images are shown at speed, this is perceived by the eye as a movement and not as a presentation of individual images, by virtue of the eye having a certain degree of inertia. In the majority of cases, only a small part of the image frame is involved in the actual movement; compare a walking person against a stationary background in this regard. This feature is used for different types of image sequence compression, such as MPEG2, for instance. MPEG2 saves space in the image sequence, by sending, among other things, approximative information that describes those pixels that change. However, this results in the introduction of errors in the image sequence, making it necessary to synchronise the image at regular intervals. This is achieved with a so-called I-image that contains all information necessary to compile a complete image.

Image sequences also include a row of different frames in order to enable a moving image to be transmitted in the most effective manner possible. A frame contains image information that is presented on a medium, possibly together with further frames, to form an image or picture. For instance, an interlaced image is comprised of two frames. The term frame will be used consistently throughout the following description. By frame is meant information that is used to compile an image. A frame can itself include a complete image, or solely parts of an image, or information from which an image can be calculated An I-frame is a complete frame that includes image information. Because an I-frame contains a great deal of information, it is expensive to transfer. A new P-frame can be formed from an I-frame or from a P-frame. A P-frame, (prediction frame) is formed by transferring to the receiver side movement vectors and DFD (Displaced Frame Difference) related to the preceding frame. The movement vectors describe how objects in the preceding frame shall be moved to form the P-frame. When the new P-frame is formed, errors will occur due to rounding-up, for instance. DFD describes how the calculated P-frame differs from the original image. The difference between the values of each pixel in the calculated frame and in the original frame can be calculated with regard to black-white frames. A colour frame that uses RGB (Red, Green, Blue) can be transformed to a form in which one portion consists of a luminance part. The luminance part can be used to calculate the DFD, in this case. A P-frame is more cost-effective than an I-frame, since movement vectors plus DFD contain much less information than a corresponding I-frame would contain. Also included are B-frames which are calculated from preceding and succeeding P-frames.

The expression subliminal message is also used to describe a code where a number of encrypted messages are encoded within the same set of symbols. This has no relationship at all with the present invention.

Described in U.S. Pat. No. 5,151,788 is a system for identifying and eliminating advertisements in and from a video signal, by detecting blank images. The concept of this solution cannot be applied to subliminal messages, because subliminal messages are not normally preceded by a blank image.

Described in FR 2,622,077 is a system for detecting discontinuities between images, by analyzing an analogue video signal line-by-line. The concept is not applicable to the present invention, since subliminal messages do not differ from other signals when considered line-by-line.

SUMMARY OF THE INVENTION

The present invention addresses the aforesaid problems, by detecting subliminal messages and warning an observer of their presence.

The object of the present invention is thus to protect an observer against subliminal messages.

The aforesaid problems are solved by the present invention, by detecting subliminal messages and warning an observer of their presence, by detecting a context change between two frames.

More specifically, there is detected a first context change between two frames. When a second context change occurs between a further two frames within a predetermined time period, the frames accommodated within the two context changes are defined as an subliminal message. When a subliminal message has been detected, an alarm is sent to an observer.

A context change can be defined as a major change in the content of a frame; c.f. a scene change, for instance.

A frame point can be defined as a value in a point in an image that together with other frame points compiles said image.

The present invention provides the advantage of enabling subliminal messages to be detected and stored for later analysis.

Another advantage is that an observer can be protected against and warned of the presence of subliminal messages.

The invention will now be described in more detail with reference to preferred embodiments thereof and also with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overview of one embodiment according to the invention.

FIG. 2 is a flowchart illustrating one embodiment of the invention.

FIG. 3 is a flowchart illustrating another embodiment of the invention.

FIG. 4 is a flowchart illustrating the detection of a context change in accordance with one embodiment of the invention.

FIG. 5 is a flowchart illustrating the detection of a context change according to another embodiment of the invention.

FIG. 6 is a flowchart illustrating the detection of a context change in accordance with still another embodiment of the invention.

FIG. 7 is a flowchart illustrating the detection of a subliminal message.

FIG. 8 illustrates a subliminal protection module.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is an overview of one embodiment of the invention. Reference numeral 101 identifies an observer or viewer watching a film on a television 102. Although the term film and television are used in describing this embodiment, it will be understood that equivalent terms can be used instead, for instance such terms as MPEG-sequence and data terminal. The reference numeral 111 identifies a frame sequence sent to the television 102 from a source 110. The sequence of frames 111 arrives at the television 102 via an SMP-module 112 (Subliminal Message Protection). The SMP-module may alternatively be integrated with the video decoder. The source 110 may, for instance, be a cable-TV distributor, an SP (Service Provider) or a computer connected to Internet or Intranet. FIG. 1 shows part of a frame sequence 111, where reference 103 identifies a frame in the normal sequence. Reference 104 also identifies a frame in the normal sequence, although in the illustrated case the frame 104 constitutes the last frame that occurs in the normal sequence prior to the occurrence of a context change 105. A context change can be defined as a major change in the content of a frame; c.f. a scene change for instance. The context change 105 is followed by a series of frames which together constitute a subliminal message 106. The subliminal message 106 may be comprised of solely one frame or of several mutually sequential frames. Reference 107 identifies a context change which terminates the subliminal message and the normal frame sequence reappears. Reference 108 identifies the first frame in the normal frame sequence, while reference 109 identifies the next following frame. The SMP-module 112 detects the context changes 105 and 107. As soon as the context changes 105 and 107 occur within a specified time interval, an alarm is generated and the subliminal message 106 is stored and can be played back by the observer 101.

FIG. 2 is a flowchart illustrating one embodiment of the invention. Reference 205 identifies a frame sequence. Reference CC1 identifies a context change between the normal frame sequence N and those frames that constitute the subliminal message S. Reference CC2 identifies a context change between the subliminal message S and the normal frame sequence N. Each frame that arrives at an SMP-module (not shown) is compared with the last frame to arrive, and context changes are detected, in accordance with box 201. The time at which the two latest context changes occurred is saved. The time difference between the latest two context changes to take place is calculated in accordance with box 202. When the time difference is smaller than a threshold value Ts, a user alarm 203 is triggered and the image frozen, in accordance with box 204. The observer is then able to ascertain whether or not he/she has been subjected to a subliminal message and, if so, the nature of the message.

FIG. 3 is a flowchart illustrating another embodiment of the invention. Reference 301 identifies a frame sequence arriving at an SMP-module (not shown). Reference CC1 identifies a context change in the frame sequence. Reference N1 identifies the last frame in the normal frame sequence, while reference S1 identifies the first frame in the subliminal message. Reference S2 identifies the last frame in the subliminal message and reference CC2 identifies a context change between S2 and N2, where N2 identifies the first frame in the normal sequence after the context change CC2. The SMP-module (not shown) functions to detect context changes, and the time at which these changes occur is saved together with the frames N1, N2, S1 and S2, in accordance with box 302. If the time difference between the latest two context changes CC1 and CC2 is smaller than a given threshold value Ts, box 303, a preliminary alarm is triggered and relevant data logged, e.g. the subliminal message source, the message arrival time, and so on, in accordance with box 304. A test is then run to ascertain whether or not a context change exists between frames N1 and N2. If no context change exists between said frames, an alarm is triggered (box 306) and the frame sequence frozen (box 307). The observer is now able to evaluate consciously the context change that has occurred, through the medium of the frozen frames and the logging activity that has ensued.

Those occasions on which the entire frame has been drastically changed, such as in the case of a scene change, can be mediated with an I-frame in the frame sequence. When the transmission of a subliminal message is commenced, there will occur a scene change that causes a major part of the frame to be changed between two mutually sequential frames. Thus, a context change can occur when the receiver receives an I-frame. When two I-frames are received in succession within a short space of time, the transmission of a subliminal message can be suspected.

FIG. 4 is a flowchart that illustrates the detection of changes with the aid of I-frames in an MPEG-sequence. Reference 401 identifies a frame sequence that arrives at an SMP-module (not shown). The SMP-unit receives a frame, box 402, and ascertains whether or not the frame received is an I-frame, box 403. The receipt of an I-frame indicates a context change, box 404.

FIG. 5 is a flowchart that illustrates the detection of a context change, by numerically calculating a value of the change between two frames. The reference 501 identifies a frame sequence arriving at an SMP-unit (not shown). The SMP-unit (not shown) receives a frame N.sub.i, box 502. The frame N.sub.i is stored in a memory L.sub.2. Prior to this, the value of L.sub.2 is stored in a memory L.sub.1, box 503. A value E of the difference between the frames is then calculated, by summating an energy measurement of the difference between corresponding frame points in the frames L.sub.1 and L.sub.2, box 504. This energy measurement may, for instance, be x.sup.2, which would give the following formula:

E=.SIGMA.(I.sub.s -I'.sub.s).sup.2

s=all pixels

where I.sub.s is the value of the frame point s in the frame L.sub.2, and I'.sub.s is the value of the frame point s in the frame L.sub.1. A context change is indicated when E is greater than a threshold value T.sub.e, in accordance with boxes 506 and 506 respectively.

As illustrated in FIG. 6, a context change between two P-frames can be detected in a manner similar to that described above, by measuring the energy in the DFD. In FIG. 6, the reference numeral 601 identifies a frame sequence. The energy is calculated, box 603, for each DFD received, box 602. If the amount of energy contained by the DFD is greater than a threshold value 604, this indicates that a context change has taken place, box 605.

The SMP may include a library function that contains data relating to known subliminal messages, as shown in FIG. 7. The reference numeral 701 identifies a frame sequence. Each frame received, box 707, is compared with the frames stored in the library, box 703, and when sufficient similarity is noted, box 704, a user alarm is triggered, box 705. This comparison may be carried out by filtering each frame, so as to present a number of characteristic features. These characteristic features are then compared with the features stored in the library function. One advantage with this procedure is that computer power and memory space are saved.

FIG. 8 illustrates in greater detail an SMP-module 802 connected to a monitor 801. A frame sequence arrives at the SMP-unit 803. The frames pass a system 807 which functions to detect context changes. The system 807 includes a part 804 whose function is to measure the energy content of a frame, a part whose function is to compare the energy value with a threshold value 808, and a part whose function is to initiate an alarm. The SMP also includes means for storing a stream or sequence of frames 806.

It will be understood that the invention is not restricted to the aforedescribed and illustrated exemplifying embodiments thereof, and that modifications can be made within the scope of the following claims.

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United States Patent	*6,292,688*
Patton	September 18, 2001

Method and apparatus for analyzing neurological response to emotion-inducing stimuli

Abstract

A method of determining the extent of the emotional response of a test subject to stimului having a time-varying visual content, for example, an advertising presentation. The test subject is positioned to observe the presentation for a given duration, and a path of communication is established between the subject and a brain wave detector/analyzer. The intensity component of each of at least two different brain wave frequencies is measured during the exposure, and each frequency is associated with a particular emotion. While the subject views the presentation, periodic variations in the intensity component of the brain waves of each of the particular frequencies selected is measured. The change rates in the intensity at regular periods during the duration are also measured. The intensity change rates are then used to construct a graph of plural coordinate points, and these coordinate points graphically establish the composite emotional reaction of the subject as the presentation continues.

Inventors:	Patton; Richard E. (Colorado Springs, CO)
Assignee:	Advanced Neurotechnologies, Inc. (Colorado Springs, CO)
Appl. No.:	608440
Filed:	February 28, 1996

Current U.S. Class: 600/544; 600/300; 600/545

Intern'l Class: A61B 005/04

Field of Search: 128/731,732,630 600/544,545,300

References Cited

U.S. Patent Documents

Re34015	Aug., 1992	Duffy	128/731.
4649482	Mar., 1987	Raviv et al.	128/731.
4736307	Apr., 1988	Salb	128/731.
4744029	May., 1988	Raviv et al.	128/731.
4789235	Dec., 1988	Borah et al.
4794533	Dec., 1988	Cohen.
4815474	Mar., 1989	Duffy	128/731.
4862359	Aug., 1989	Trivedi et al.	128/731.
4955388	Sep., 1990	Silberstein.
5024235	Jun., 1991	Ayers.
5113870	May., 1992	Rossenfeld.
5137027	Aug., 1992	Rosenfeld.
5230346	Jul., 1993	Leuchter et al.
5243517	Sep., 1993	Schmidt et al.
5331969	Jul., 1994	Siberstein	128/731.
5339826	Aug., 1994	Schmidt et al.
5392788	Feb., 1995	Hudspeth.

Primary Examiner: Peffley; Michael
Attorney, Agent or Firm: Vedder Price Kaufman & Kammholz

Claims

What is claimed is:

1. A method of determining the extent of the emotional response of a test subject to stimuli in the form of a presentation having at least a time-varying visual content, said method comprising preparing a presentation having stimuli in the form of a time-varying visual content, positioning at least one test subject to observe said presentation including said stimuli for a given duration, establishing a path of communication between said at least one subject and a brain wave detector/analyzer capable of measuring at least an intensity component of each of at least two different brain wave frequencies, each of which is associated with a base emotion, permitting said at least one subject to view said presentation, recording periodic variations in said intensity component of said brain waves at each of the particular frequencies selected, recording the change rates in each of said intensity components periodically during said duration of the presentation, and using said intensity change rate data to construct a graph comprised of plural coordinate points each having a component along each of two axes, with all of said coordinate points graphically establishing the composite emotional state of said subject to said presentation.

2. A method of determining a correlation between a composite emotional state desired to be imparted to a test subject by making an audio visual presentation to said subject and the emotional state actually induced in said subject by making said presentation, said method comprising identifying at least two basic emotion scales, including a pleasure/displeasure scale and an arousal/indifference scale, determining an electroencephalographic brain wave frequency associated with each of said scales, making an audio/visual presentation to at least one test subject while said subject is connected to a brain wave detector/analyzer associated with an electroencephalographic brain wave pickup, noting a variation from time to time in an amplitude of brain waves at each characteristic frequency during the presentation, recording the change rates and directions of said amplitudes at a plurality of intervals during said presentation, and thereafter, using a plot of said amplitude change rates, creating a graph whose points represent coordinate points derived from said changes along a given axis for each of two basic emotion scales, said coordinate points thereby representing on a circumplex display the emotional states of the test subject from time to time.

3. A method of determining whether an advertising presentation affects a test subject exposed to said presentation, said method comprising presenting advertising material having a given content to a subject by way of an audio/visual presentation; selecting at least two frequencies, each characteristic of a measurable base emotion in a human subject and recording the intensity of an electroencephalographic signals having values generated by the subject over a number of sampling intervals during viewing of the presentation, by the subject, recording said values and change rates of said values on a plurality of scales, each corresponding to one of the selected frequencies, graphically determining a composite emotional state of said subject for each sub-interval of a plurality of sub-intervals wherein said presentation is being made, subsequently presenting to the subject advertising material having a content that is different from but is thematically related to the original advertising material; and subsequently recording and analyzing the emotional state of the subject subsequent to the presentation of the thematically related material during a time following said second presentation when portions only of said original presentation are brought to the attention of said subject.

4. A method of altering an advertising presentation having a given content, said method comprising selecting at least one test subject, placing the test subject in communication with an electroencephalographic pick up and brain wave detector/analyzer capable of recording and analyzing spectral data associated with the subject, constructing a composite emotional state profile of the subject using variations of at least two measurable base emotions in the subject, including the emotions of pleasure and arousal, determining whether the composite emotional state of the test subject corresponds to that intended to be imparted by the advertising presentation; noting where the subject has failed to attain the desired emotional state; revising the content of the advertising message in part and retesting the subject using the same methods to determine whether such content changes have succeeded in altering the composite emotional state of said test subject.

5. A method of determining the extent of an emotional response of a test subject to an advertising presentation having audio/visual content, said method comprising preparing a presentation having a time-varying audio/visual content and intended to elicit a particular overall emotional response in an audience to whom viewing said presentation will ultimately be made, positioning at least one test subject in a position to observe said presentation for a given duration, establishing a path of communication between said at least one subject and an electroencephalographic brain wave detector and a brain wave analyzer capable of measuring the intensity of brain wave signals of two different frequencies, a first frequency associated with the emotion of pleasure and a second frequency associated with the base emotion of arousal, permitting said at least one subject to view said presentation and recording the absolute values of brain wave intensity at plurality of intervals during the time when said subject is viewing said presentation, thereby subdividing said presentation into a plurality of sub intervals, thereafter determining the change of intensity and intensity change rates of both selected brain wave frequencies, using the changes of intensity of each point relative to a preceding point to establish values for each of said sub intervals, creating a two-axis, pleasure v. arousal graph having a plurality of coordinate points each representing a pair of the marginal values, one taken from each of said pleasure and arousal scales, and thereafter graphically determining the emotional state of the test subject at each sub interval of the presentation, and an emotional history of the subject during the presentation, and comparing the achieved emotional response of the test subject to the intended response to determine whether changes in the content of the presentation are indicated so as to increase the likelihood that the audience intended to view the presentation will display the intended emotional response.

6. A method as defined in claim 5, wherein said at least one test subject comprises a plurality of test subjects.

7. A method as defined in claim 5, wherein said at least one test subject comprises at least 10 test subjects, and wherein an emotional history of said subjects is determined by statistically analyzing all of said test subjects as a group.

8. A method as defined in claim 5, which further includes measuring the intensity of brain wave signals at a third frequency, said third frequency being associated with dominance, and which further includes creating two additional two-axis graphs, each of said graphs having four quadrants one comparing pleasure and dominance and the other comparing arousal and dominance, and said method also including determining said composite emotional state of said test subject by noting the quadrant in which coordinate points are located and comparing such coordinate points with a predetermined description of the content of such quadrant.

9. A method of determining the extent of an emotional response of a test subject to an advertising presentation, said method comprising preparing a presentation having a time-varying content and intended to elicit a particular overall emotional response in an audience to whom viewing said presentation will ultimately be made, positioning at least one test subject capable of capable of undergoing individual emotional responses each represented by a particular frequency and intensity in a position to observe said presentation for a given duration, establishing a path of communication between said at least one subject and an electroencephalographic brain wave detector and a brain wave analyzer capable of measuring an intensity characteristic of brain wave signals of a plurality of substantially exact but different frequencies, each of said frequencies being associated with a predetermined base emotion, permitting said at least one subject to view said presentation and recording the absolute values of said brain wave intensity characteristic at a plurality of intervals during said duration when said subject is viewing said presentation, thereby subdividing said duration into a plurality of individual time segments, thereafter determining the intensity characteristic changes and intensity characteristic change rates of said plurality of brain wave frequencies, using the changes of said intensity characteristic of each point relative to a preceding point to establish marginal values for each of said time segments, creating at least one two-axis graph, said graph having axes corresponding to two of said base emotions and including a plurality of coordinate points each representing a pair of the marginal values taken from a selected emotion scale, thereafter graphically determining the composite emotional state of the test subject at each segment of the presentation, and comparing the achieved emotional response of the test subject to the response intended to be achieved to determine whether changes in the content of the presentation are indicated so as to increase the likelihood that the audience intended to view the presentation will display the intended emotional response.

10. A method as defined in claim 1, wherein said advertising presentation is a television commercial.

11. A method as defined in claim 1, wherein said advertising presentation is an audio presentation.

12. A method as defined in claim 1, wherein said at least one test subject comprises a plurality of test subjects.

13. A method as defined in claim 1, wherein said at least one test subject comprises at least 10 test subjects.

14. A method as defined in claim 13, which further includes applying statistical analysis to the results of the test subjects.

15. A method as defined in claim 13, wherein a determination of the emotional state of each of said test subjects is made by determining the number and duration of quadrant visits of each of said subjects without precisely determining the emotional state of each of said test subjects.

16. A method as defined in claim 1, wherein said intensity characteristic of said brain wave signals comprises the amplitude of said brain wave signals.

17. A method as defined in claim 1, wherein said plurality of frequencies includes frequencies of 8 Hz, 16 Hz, and 26 Hz.

18. A method as defined in claim 1, wherein said predetermined base emotions are pleasure and arousal.

19. A method as defined in claim 1, wherein said plurality of different frequencies includes five frequencies, the base emotions relating to said frequencies being pleasure, arousal, dominance, comprehension and pictorial comprehension.

20. A method as defined in claim 1, wherein each of said individual time segments comprises a segment of not more than two seconds duration.

21. A method as defined in claim 1, wherein said presentation has a duration of from about 15 seconds to about 1 minute.

22. A method as defined in claim 1, which further includes determining the emotional response of the test subject during presentation and comparing said emotional response of the test subject to the content of the presentation as a method of further analyzing said presentation.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to methods and apparatus for neurological testing, and more particularly, to methods and apparatus for determining the emotional state of an individual over the period of time during which that individual is being exposed to time-varying stimuli. While in one respect the invention applies to determining the neurological, psychological, or emotional response of an individual to test stimuli, in many instances, the invention is applicable to using individuals to test a program containing certain stimuli, in order to determine whether such a program will subsequently create favorable responses in other individuals of similar sociocultural-economic makeup.

One of the most practical applications of the method and apparatus with which the invention is presently concerned is that of consumer response testing. Accordingly, this aspect of the method will be discussed immediately herein, while a discussion of other applications and purposes implicit in the invention will be set out elsewhere herein.

In the United States, and elsewhere throughout the world, advertising is heavily used to promote consumer, commercial and industrial products. It is almost universally accepted that, as between or among products which are generally similar to one another in content, price, or quality, successful advertising can help a particular product achieve much greater market penetration and financial success than an otherwise similar product. Advertising, and particularly consumer advertising, although a multi-billion dollar industry in the United States alone, is an area wherein workers find it extremely difficult to create and reproduce what prove to be consistently successful advertising campaigns, themes, or other materials. It is likewise accepted that while it is often easy to predict that response to a particular proposed advertisement or campaign will be unfavorable, it is not known how to create indivi

Current U.S. Class:	348/563; 348/473
Intern'l Class:	H04N 005/445
Field of Search:	348/473,589,563,584,600,598,525,521

Current U.S. Class:	600/28
Intern'l Class:	A61B 005/00
Field of Search:	600/26-28 128/897,898

Current U.S. Class:	375/240.13; 348/154; 348/473; 348/699; 358/908
Intern'l Class:	H04N 005/14; H04N 009/64
Field of Search:	346/46,94 358/908 348/699,700,473,475,553,154,155

Current U.S. Class:	600/544; 600/300; 600/545
Intern'l Class:	A61B 005/04
Field of Search:	128/731,732,630 600/544,545,300