A Bio-Inspired Vision Sensor With Dual Operation and Readout Modes

Abstract

This paper presents a novel event-based vision sensor with two operation modes: 1) intensity mode and spatial contrast detection. They can be combined with two different readout approaches: 1) pulse density modulation and time-to-first spike. The sensor is conceived to be a node of an smart camera network made up of several independent an autonomous nodes that send information to a central one. The user can toggle the operation and the readout modes with two control bits. The sensor has low latency (below 1 ms under average illumination conditions), low power consumption (19 mA), and reduced data flow, when detecting spatial contrast. A new approach to compute the spatial contrast based on inter-pixel event communication less prone to mismatch effects than diffusive networks is proposed. The sensor was fabricated in the standard AMS4M2P 0.35-µm process.A detailed system-level description and experimental results are provided.

Applications of event‐based image sensors—Review and analysis

“…Another strength is their high dynamic range (HDR) operation. Pixel spiking frequencies can span more than five decades . This implies the capacity of detecting intrascene illumination levels with a dynamic range higher than 100 dB.…”

“…Their main disadvantage is image quality. Fixed‐pattern noise is typically higher in these sensors . However, there are many applications that sacrifice image quality over speed, HDR operation, and low power consumption.…”

“…A recent alternative to build digital sun sensors is the usage of octopus retinas . By placing a dedicated optics over them, only pixels exposed to sunlight will send data.…”

“…A, Operation of a sun sensor built with a pinhole lens. B, Snapshot of an asynchronous sun sensor implemented with a pinhole lens.…”

Sun Sensor Based on a Luminance Spiking Pixel Array

“…Time-to-first-spike (TFS) operation [10], [18]- [20] is very efficient in terms of data processing when determining the sun position. In this operation mode, pixels are activated after releasing the RES signal in Fig.…”