Temporal contrast AER pixel with 0.3%-contrast event threshold

Bioluminescence analysis methods require measurement of small temporal variations of scene brightness over a 2d spatial array. Conventional solutions use low-noise frame-based image sensors and high resolution ADCs to achieve the required sensitivity to small fluctuations of less than 1%. Here we report a pixel design for address event representation (AER) temporal contrast detection that is optimized for detecting small relative changes of intensity. Detected changes exceeding a threshold asynchronously generate events. The pixel uses two successive gain stages to memorize and amplify changes of intensity, allowing detection of changes as small as 0.3% of intensity; a factor of about 50 better than prior capabilities for event-based temporal contrast sensors.