An orientation selective 2D AER transceiver

This paper describes an address event representation (AER) transceiver chip that accepts 2D images and produces 2D output images equal to the input filtered by even and odd symmetric orientation selective spatial filters. Both input and output are encoded as spike trains using a differential ON/OFF representation, conserving energy and AER bandwidth. The spatial filtering is performed by symmetric analog circuits that operate on input currents obtained by integrating the input spike trains, and which preserve the ON/OFF representation. This chip is a key component of a multi-chip system we are constructing that is inspired by the visual cortex. We present measured results from a 32 × 64 pixel prototype, which was fabricated in the TSMC 0.25 μm process on a 3.84 mm by 2.54 mm die. Quiescent power dissipation was 3 mW.