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Signals relevant to counter-terror.

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Signals relevant to counter-terror.

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  1. Computer vision approaches to identifying people and possible malfeasant behavior. Dimitris N. Metaxas Mark G. FrankDirector, Computational Biomedicine School of Communication, Imaging & Modeling Center Information & Library Studieswith special thanks to:Paul Ekman, UCSF;Sinuk Kang, Amy Marie Keller, Anastacia Kurylo, Maggie Herbasz, Belida Uckun, Rutgers;Jeff Cohn, Pitt; Takeo Kanade, CMU; Javier Movellan & Marni Bartlett, UCSD.David Dinges, UPENNAlso thanks to: Office of Naval Research, National Science Foundation (ITR program), AFOSR, DARPA M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  2. M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  3. Signals relevant to counter-terror. • Identification of bad guys • Changes in gait with loads as small as 1 kg • Anger prior to imminent attack • Fear/distress when lying M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  4. Take a closer look… Kim Philby, 1960’s (Frank & Ekman, 2003) M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  5. How lies are betrayed.Lie Cognitive clues Emotional clues Lying about feelings Feelings about lying • - Contradictory statements • Hesitations • Speech errors • Reduced illustrators • Contradictory emblems • Reduced detail • Etc. -Look for reliable signs of emotion • -Duping delight • Guilt • Detection • apprehension M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  6. The Facial Action Coding System (FACS) Ekman & Friesen, 1978 46 Action Units Action code: 1, 2, 4, 5, 7, 20, 26 1 Inner brow raise 2 Outer brow raise 4 Brow lower 5 Upper lid raise 7 Lid tighten 20 Lip stretch 26 Jaw drop M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  7. Challenges facing behavioral science: • Advantages: - reliably identify people & behaviors - non-obtrusive - non-inferential, allows for discovery • Disadvantage: - laborious - mistaken identity via cognitive capacity, disguise, etc • Solution - automatic computer vision techniques M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  8. Gait recognition • Identify people from the way they walk • Important for surveillance and intrusion detection • What are good features for identifying a person? • i.e., what features are person-specific? M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  9. Background Sagittal plane - divides body into left and right halves Limb segment - a vector between two sites on a particular limb M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  10. Elevation Angles M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  11. The trajectories of the sagittal elevation angles are invariant across different subjects. As a consequence, person-independent gait recognition will require less training data. (Borghese et al., 1996) M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  12. The cyclogram • Elevation angles trace curve in a 4D space • Curve is called “cyclogram” • Cyclogram lies in a 2D plane • Well, almost • Hypothesis: deviation of cyclogram from plane is person-specific M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  13. Cyclogram example Curve is cyclogram projected into best-fit plane Green points are real points of cyclogram Red lines trace the deviation of points from plane (exaggerated scale) M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  14. Cyclogram sequence • Deviation from cyclogram plane can be represented as a sequence • e.g., CCCGTTTTATATTTTTAAAAGCCGGTAAATTAGGGG • Compare sequences between people via longest common subsequence (LCS) matching • Well-known dynamic programming algorithm, used in computational biology M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  15. Examples of People Detection M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  16. Examples of Gait Analysis M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  17. Face: Tracking: Stress Recognition • Identify which Facial Features (space and time) are important to recognize stress • Assymetries and Movements around the mouth and eyebrows M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  18. Slope = Asymmetry A horizontal line would indicate no asymmetry. This facial expression, however, is generally slanted upward and to the left. M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  19. asymmetry time Expression of high stress in form of asymmetrical facial expression Plots of high and low stress M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  20. asymmetry time In contrast, low stress M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  21. Some more high stress from different subjects M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  22. Face: Tracking: Stress Recognition M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  23. Face: Tracking: Stress Recognition M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  24. M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  25. Subtle brow changes important. M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  26. Technical Challenges. • Pose • Head motion • Occlusion from glasses, facial hair, rotation, hands • Talking • Video quality • Frame rate (blinks) M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

  27. Conclusions. • There are reliable means to identify people as well as behaviors associated with deception and hostile intent. • We can detect these behaviors. • We can represent them digitally. • Can this make us more secure? M. Frank & D. Metaxas - Rutgers HMS Symposium 2003

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