Event-Based Neuromorphic Systems

3

Silicon Retinas

This chapter introduces biological and silicon retinas, focusing on recently developed silicon retina vision sensors with an asynchronous address-event output. The first part of the chapter introduces biological retinas and four examples of Address-Event Representation (AER) retinas. The second part of the chapter discusses the details of some of the pixel designs and the specifications of these sensors. The discussion focuses on future goals for improvements.

3.1   Introduction

Chapter 2 discussed the event-based communication architectures for neuromorphic systems, and this chapter focuses on state-of-the-art electronic models of biological retinas that use this communication fabric to transmit their output data. Electronically emulating the retina has been a major target of neuromorphic electronic engineers since the field’s earliest times. When Fukushima et al. (1970) demonstrated his discrete model of the retina, it generated excitement although the practical industrial impact was miniscule. Nonetheless it probably inspired an entire generation of young Japanese engineers to work on cameras and vision sensors, which was evident in a Japanese domination of the electronic imager market which lasted for several decades. Likewise, Mahowald and Mead (1991) on the cover of Scientific American was an inspiration to a generation of American neuromorphic electronic ...