Quadratic Gabor filters for object detection

We present a new class of quadratic filters that are capable of creating spherical, elliptical, hyperbolic and linear decision surfaces which result in better detection and classification capabilities than the linear decision surfaces obtained from correlation filters. Each filter comprises of a number of separately designed linear basis filters. These filters are non-linearly combined using an algorithm called the extended piecewise quadratic neural network (E-PQNN). We consider the use of Gabor basis filters; the Gabor filter parameters are separately optimized; the fusion parameters used to combine the Gabor filter outputs are optimized using the conjugate gradient method; they and the non-linear combination of filter outputs are included in our E-PQNN algorithm. We present results obtained for an infra-red (IR) vehicle detection problem