IMAGING FACIAL SIGNS OF NEURO-PHYSIOLOGICAL RESPONSES

• US 20090080730A1
• Filed: 09/25/2008
• Published: 03/26/2009
• Est. Priority Date: 09/25/2007
• Status: Active Grant

• Current Assignee: University of Houston System
• Original Assignee: University of Houston System
• Inventors: PAVLIDIS, Ioannis
• Granted Patent: US 8,401,261 B2
• Time in Patent Office: Days
• US Class Current: 382/128
• CPC Class Codes: A61B 5/015 By temperature mapping of body part
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: G06V 2201/03 Recognition of patterns in medical or anatomical images
• CPC Class Codes: G06V 40/168 Feature extraction; Face representation

Abstract

The invention provides an integrated framework for detecting peripheral sympathetic responses through imaging. The measurements may be performed on three facial areas of sympathetic importance, that is, periorbital, supraorbital, and maxillary. Because the imaging measurements are thermal in nature and comprise multiple components of variable frequency (i.e., blood flow, sweat gland activation, and breathing), wavelets are used as the image analysis framework. The image analysis may be grounded on GSR signals.

Claims

1. A method for quantifying at least one sympathetic response on the face, the method comprising measuring signals from at least one facial region selected from the group consisting of supraorbital, periorbital, and maxillary regions.

2. The method of claim 1 wherein said sympathetic responses are quantified through measurement of at least one selected from the group consisting of blood flow in the facial/ophthalmic arteriovenous complex, blood flow in the supraorbital area, perspiration in the supraorbital area, and perspiration in the maxillary area.

3. The method of claim 2 comprising obtaining at least one measurement via thermal imaging.

4. The method of claim 2 comprising obtaining of at least one corroborating probe signal selected from palm perspiratory signals extracted through GSR, thermal signals extracted through thermistor sensors, and breathing signals extracted through a piezo-respiratory belt transducer.

5. The method of claim 4 wherein at least one of the corroborating probe signals is synchronized with the measurement via thermal imaging.

6. The method of claim 2 wherein the at least one sympathetic response is quantified through wavelets analysis.

7. The method of claim 6 comprising a multi-resolution wavelets approach.

8. A method for modeling Galvanic Skin Response (GSR) signal data, the method comprising:

segmenting the signal data; and

approximating each segment using a mathematical function.

9. The method of claim 8 wherein at least one of the curve segments is further divided into one or more subsegments.

10. The method of claim 8 wherein approximation by mathematical functions is performed separately for each curve segment, each subsegment, or both.

11. The method of claim 10 wherein the mathematical function is selected from the group consisting of Laplace distribution functions, Gaussian distribution functions, Lorentzian distribution functions, Delta distribution functions, exponential functions, and linear functions.

12. The method of claim 11 wherein the mathematical function is a truncated form.

13. The method of claim 8 wherein each segment is further segmented into a Left Subsegment, a Right Subsegment, and a Left Stimulus Onset Subsegment.

14. A method for localizing and/or comparing the phasic and tonic response components of at least one physiological channel selected from the group consisting of blood flow in the facial/ophthalmic arteriovenous complex, blood flow in the supraorbital area, perspiration in the supraorbital area, and perspiration in the maxillary area, the method comprising determining local maxima in the wavelet energy curves of signals obtained from the at least one physiological channel.

15. The method of claim 14 wherein the wavelet energy curves are determined using a Continuous Wavelet Transform (CWT) with a Daubechies-10 mother wavelet.

16. The method of claim 15 further comprising determining if the local maxima correspond to phasic or tonic responses.

17. The method of claim 16 further comprising comparing the relative contributions of phasic and tonic responses in at least one signal.

18. A method for comparing phasic and tonic response components between at least one sympathetic channel selected from supraorbital, periorbital, maxillary and the Galvanic Skin Response (GSR), the method comprising:

determining phasic and tonic response components for at least one sympathetic channel selected from supraorbital, periorbital, and maxillary;

determining phasic and tonic response components for GSR; and

comparing the phasic and tonic response components so obtained.

19. A method of extracting a breathing component from thermal imaging signal data obtained from the maxillary area of the face, the method comprising:

performing multi-resolution wavelets analysis to determine phasic and tonic components; and

examining the lower scale (higher frequency) wavelet energy for extraneous modulation indicative of a breathing component.

20. A system for quantifying at least one sympathetic response on the face, the system comprising:

a thermal imager adapted to measure signals from at least one facial region selected from the group consisting of supraorbital, periorbital, and maxillary regions.

21. The system of claim 20 wherein the measured signal is at least one selected from the group consisting of blood flow in the facial/ophthalmic arteriovenous complex, blood flow in the supraorbital area, perspiration in the supraorbital area, and perspiration in the maxillary area.

22. The system of claim 21 further comprising at least one ground-truth probe synchronized with the thermal imager via an electronic circuit.

23. The system of claim 22 wherein the at least one ground-truth probe is selected from GSR sensors, thermistor sensors, piezo-respiratory belt transducers, and combinations thereof.

24. The system of claim 20 further comprising a computer in communication with the thermal imager.

25. The system of claim 24 wherein the computer is adapted to perform wavelet energy analysis on the measured signal.