Event-Based Pixel Sensitive to Changes of Color and Brightness

Vision sensors whose pixels asynchronously generate informative output events are gathering increasing interest because they can reduce the data latency, rate, and redundancy, while also increasing dynamic range. This paper proposes such a dynamic vision sensor (DVS) pixel which is aimed at color vision (cDVS). The pixel combines subthreshold continuous time analog circuits with event-driven switched capacitor amplifiers and asynchronous digital outputs. The cDVS simultaneously detects separate log-intensity and wavelength change events using a single buried double junction (BDJ) photodiode. Chip measurements show that the cDVS color change pathway can detect light wavelength changes as small as 15 nm while the cDVS relative intensity change pathway detects changes as small as 10% of intensity. The circuit is characterized and improvements are proposed.