A low-power orientation-selective vision sensor

We describe the implementation of a focal plane array for computing the outputs of orientation-selective filters similar to Gabor filters using weak inversion transistor circuits. Both the scale and orientation selectivity of the filter can be tuned electronically. We exploit the concept of the transistor as a pseudo-conductance or diffuser, and use current, rather than voltage, to represent signals of interest, This design enables energy efficient computation of the filter responses with similar circuit complexity as compared with previous strong inversion designs. Test results from a 12 x 14 pixel array fabricated in 1.2-mu m technology are presented.