A Dynamic Vision Sensor With 1% Temporal Contrast Sensitivity and In-Pixel Asynchronous Delta Modulator for

Abstract

A dynamic vision sensor (DVS) encodes temporal contrast (TC) of light intensity into address-events that are asynchronously transmitted for subsequent proc essing. This paper describes a DVS with improved TC sensitivity and event encoding. To enhance the TC sensitivity, each pixel employs a common-gate photoreceptor for low output n oise and a capaci- tively-coupled programmable gai n amplifier for continuous-time signal amplification without sac rificing the intra-scene dynamic range. A proposed in-pixel asynch ronous delta modulator (ADM) better preserves signal integrity in event encoding compared with self-timed reset (STR) use d in previous DVSs. A 60 30 prototype sensor array with a 31.2 mp i x el pitch was fabricated in a 1P6M 0.18 m CMOS technology. It consumes 720 W at a 100k event/s output rate. Measurements show that a 1% TC sensitivity with a 35% relative standard de viation is achieved and that the in-pixel A D Mi su pt o3 . 5t i m e sl e s ss u s c e p t i b l et os i g n a ll o s st h a nS T R in terms of event numbe r. These improvements can facilitate the application of DV Ss in areas like optical neuroimaging which is demonstrated in a simulated experiment.