US6021346A
Expired / Lapsed
US
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Method for determining positive and negative emotional states by electroencephalogram (EEG)
Assignee: Electronics and Telecommunications Research Institute
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Filing: 1998-07-23
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Granted: 2000-02-01
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Expires: 2018-07-23
Abstract
Abstract The present invention to provide a method for determining positive and negative emotional states by using a relative power in a subband of a specific frequency band increases or decreases in the course of time. In order to realize the above object, the present invention determines positive and negative emotional states by using a relative power in a subband of a specific frequency band increases or decreases with the lapse of time. The present invention performs a Fourier transform for a unit time not an entire response time regarding a stimulus, and can be used in real time by using a time-frequency analysis method continuously executed with the lapse of time.
Inventors
- 👤 Chang Su Ryu
- 👤 Seon Hee Park
- 👤 Seung Hwan Kim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:19
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/16; A61B5/165; A61B5/24; A61B5/316; A61B5/369; A61B5/372; A61B5/374; A61B5/72; A61B5/7235; A61B5/7253; A61B5/7257
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
243 words
A method for determining positive and negative emotional states of a subject with an electroencephalogram (EEG) which uses a Fourier transform, comprising the steps of: a. performing a fast Fourier transform on an EEG signal measured by an electrode attached to a scalp of the subject during a specific unit of time; b. dividing a specific frequency band of the Fourier-transformed EEG signal from step a. into subbands and calculating a relative power; c. repeating steps a. and b. and calculating the relative power relative to time in the subbands; d. performing a smoothing operation for obtaining an average value of the relative power measured in step c. and neighboring data, thereby ignoring fluctuations within short periods of time; e. calculating a slope as a function of time using a least square fit for the smoothed data of step d.; f. introducing a threshold value into the slope calculated in step e. and determining an increase or decrease against time in response to the threshold value of the slope calculated in step e.; g. determining an emotional state as a negative emotional state if a low frequency component having the slope in step e. decreases during step f. or if a high frequency component having the slope in step e. increases during step f.; and h. determining an emotional state as a positive emotional state when the low frequency component increases in step f. or the high frequency component decreases in step f.
Claim 2
Independent Claim
243 words
A method for determining positive and negative emotional states of a subject with an electroencephalogram (EEG) which uses a Fourier transform, comprising the steps of: a. performing a fast Fourier transform on an EEG signal measured by an electrode attached to a scalp of the subject during a specific unit of time; b. dividing a specific frequency band of the Fourier-transformed EEG signal from step a. into subbands and calculating a relative power; c. repeating steps a. and b. and calculating the relative power relative to time in the subbands; d. performing a smoothing operation for obtaining an average value of the relative power measured in step c. and neighboring data, thereby ignoring fluctuations within short periods of time; e. calculating a slope as a function of time using a least square fit for the smoothed data of step d.; f. introducing a threshold value into the slope calculated in step e. and determining an increase or decrease against time in response to the threshold value of the slope calculated in step e.; g. determining an emotional state as a negative emotional state if a low frequency component having the slope in step e. decreases during step f. or if a high frequency component having the slope in step e. increases during step f.; and h. determining an emotional state as a positive emotional state when the low frequency component increases in step f. or the high frequency component decreases in step f.
Claim 3
Dependent Claim
29 words
The method of claim 1, wherein said step a. comprises setting a position of the electrode to one of F4 or F3 in the 10-20 international electrode placement system.
Claim 4
Dependent Claim
36 words
The method of claim 1, wherein said step b. comprises selecting an α-wave (8-13 Hz) as the specific frequency band, the α-wave being insensitive to artifacts including an eye blink, eye movement, and an electromyogram (EMG).
Claim 5
Dependent Claim
92 words
The method of claim 3, wherein said step b. comprises dividing the specific frequency band into subbands A (8-9 Hz), B (9-10 Hz), C (10-11 Hz), and D (11-12 Hz), obtaining spectral powers P A , P B , P C , and P D from respective subbands A, B, C, and D and dividing the spectral powers P A , P B , P C , and P D by a total power P A +P B +P C +P D of the specific frequency band for calculating the relative power.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 2003-01-31 | 2003-08-02 | 2004-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-01-31 | 2007-08-02 | 2008-02-01 | $3760.00 | Window Closed / Lapsed |
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