4.1 A 640×480 dynamic vision sensor with a 9µm pixel and 300Meps address-event representation

Abstract

We report a VGA dynamic vision sensor (DVS) with a 9µm pixel, developed through a digital as well as an analog implementation. DVS systems in the literature try to increase spatial resolution up to QVGA [1–2] and data rates up to 50 million events per second (Meps) (self-acknowledged) [3], but they are still inadequate for high-performance applications such as gesture recognition, drones, automotive, etc. Moreover, the smallest reported pixel of 18.5µm is too large for economical mass production [3]. This paper reports a 640×480 VGA-resolution DVS system with a 9µm pixel pitch supporting a data rate of 300Meps for sufficient event transfer in spite of higher resolution. Maintaining acceptable pixel performance, the pixel circuitry is carefully designed and optimized using a BSI CIS process. To acquire data (i.e., pixel events) at high speed even with high resolution (e.g., VGA), a fully synthesized word-serial group address-event representation (G-AER) is implemented, which handles massive events in parallel by binding neighboring 8 pixels into a group. In addition, a 10b programmable bias generator dedicated to a DVS system provides easy controllability of pixel biases and event thresholds.