A bio-inspired AER temporal tri-color differentiator

The paper presents the first focal plane array of asynchronous event pixels that react to temporal color contrast of three different color spectra. The three different spectra are transduced into photo currents by stacked photo diodes and temporal changes of the contrast of these three spectra are quantified as pulse density modulated signals and conveyed offchip by the Address Event Representation (AER) protocol. 16 × 16 pixel array has been implemented and tested in a 90 nm TSMC CMOS process. A single pixel measures 82 μm × 82 μm and has a fill factor of 27% and a dynamic range of 5 decades. The paper presents single pixel characteristics and shows visualization examples of the pixel array.