We present a 32 32 pixels contrast retina microchip that provides its output as an address event representation (AER) stream. Spatial contrast is computed as the ratio between pixel\udphotocurrent and a local average between neighboring pixels obtained with a diffuser network. This current-based computation\udproduces an important amount of mismatch between neighboring pixels, because the currents can be as low as a few pico-amperes. Consequently, a compact calibration circuitry has been included\udto trimm each pixel. Measurements show a reduction in mismatch standard deviation from 57% to 6.6% (indoor light). The paper describes\udthe design of the pixel with its spatial contrast computation and calibration sections. About one third of pixel area is used for a 5-bit calibration circuit. Area of pixel is 58 m 56 m, while its current consumption is about 20 nA at 1-kHz event rate. Extensive experimental results are provided for a prototype fabricated in a\udstandard 0.35- m CMOS process.
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机译：我们提出了一个32 32像素对比度的视网膜微芯片，该芯片提供其输出作为地址事件表示（AER）流。将空间对比度计算为像素\ udphotocurrent与通过扩散网络获得的相邻像素之间的局部平均值之比。这种基于电流的计算会在相邻像素之间产生大量的失配，因为电流可能低至几个皮安。因此，已经包括了紧凑的校准电路，以修整每个像素。测量表明，不匹配标准偏差从57％降低到6.6％（室内照明）。本文介绍了像素的设计及其空间对比度计算和校准部分。约三分之一的像素面积用于5位校准电路。像素面积为58 m 56 m，而在1-kHz事件发生率下，其电流消耗约为20 nA。提供了以标准的0.35-m CMOS工艺制造的原型的大量实验结果。
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