A Bio-Inspired AER Temporal Tri-Color Differentiator Pixel Array

Abstract

This article investigates the potential of a bio-inspired vision sensor with pixels that detect transients between three primary colors. The in-pixel color processing is inspired by the retinal color opponency that are found in mammalian retinas. Color transitions in a pixel are represented by voltage spikes, which are akin to a neuron's action potential. These spikes are conveyed off-chip by the Address Event Representation (AER) protocol. To achieve sensitivity to three different color spectra within the visual spectrum, each pixel has three stacked photodiodes at different depths in the silicon substrate. The sensor has been fabricated in the standard TSMC 90 nm CMOS technology. A post-processing method to decode events into color transitions has been proposed and implemented as a custom interface to display real-time color changes in the visual scene. Experimental results are provided. Color transitions can be detected at high speed (up to 2.7 kHz). The sensor has a dynamic range of 58 dB and a power consumption of 22.5 mW. This type of sensor can be of use in industrial, robotics, automotive and other applications where essential information is contained in transient emissions shifts within the visual spectrum.

HSMD: An Object Motion Detection Algorithm Using a Hybrid Spiking Neural Network Architecture

“…Lichsteiner et al [32] introduced the concept of an Address-Event Representation (AER) silicon retina chip capable of generating events proportional to the log intensity changes. Farian et al [33] proposed an in-pixel colour processing approach inspired by the retinal colour opponency, using the same AER concept. Brandli et al [34] proposed a new version of the AER camera reported by Lichsteiner [32] called the dynamic, active pixel vision sensor (DAVIS), which exploits the efficiency of the AER protocol and introduces a new synchronous global shutter frame concurrently.…”

Event-based Vision: A Survey

“…Color: Most diurnal animals have some form of color vision, and most conventional cameras offer color sensitivity. Early attempts at color sensitive event cameras [86], [87], [88] tried to use the "vertacolor" principle of splitting colors according to the amount of penetration of the different light wavelengths into silicon, pioneered by Foveon [89], [90]. However, it resulted in poor color separation performance.…”

Applications of event‐based image sensors—Review and analysis

“…The excellent temporal resolution of DVSs has made possible to track fast movements of particles in fluids, reducing the data throughout Color change detection . Combining the pixel architecture of a DVS with stacked photodiodes at different depths in standard silicon, it was possible to create an image sensor whose pixels only react to color changes (transient shifts within the spectrum). Stereo vision .…”