ON MEASURING TRAJECTORY-INVARIANT GAIT SIGNATURES

Biometrics are increasingly important as a means of personal identification, and as such automatic gait analysis is emerging as one of the most promising new techniques for non-contact subject recognition. There are many problems associated with obtaining a gait signature automatically, in particular the effects of footwear, clothing and walking speed. Furthermore, laboratory studies have constrained subjects to walk in a plane normal to the camera's view and have ignored the effects of pose. Methodologies based on modelling human walking offer the opportunity to develop analytic pose compensation techniques; here we develop a new geometric correction to the measurement of the hip rotation angle, based on the known orientation to the camera, using the invariance properties of angles under geometric projections. We present experimental results showing the application of our corrections to geometric targets and a real human walker. We also indicate that it is possible to derive the corrections from the gait data itself. As such we demonstrate that it is indeed possible, by geometric analysis, to provide invariant signatures for automatic gait recognition.