Title

A vision sensor with on-pixel ADC and in-built light adaptation mechanism

Document Type

Journal Article

Publisher

Elsevier Science

Faculty

Computing, Health and Science

School

Engineering and Mathematics

RAS ID

431

Comments

Originally published as: Bermak, A., Bouzerdoum, A., & Eshraghian, K. (2002). A vision sensor with on-pixel ADC and in-built light adaptation mechanism. Microelectronics Journal, 33(12), 1091-1096. Original article available here

Abstract

In this paper we propose an on-pixel Analogue-to-Digital Converter (ADC) based on pulse frequency modulation (PFM) scheme. This PFM based converter presents a viable solution for pixel-level based ADC. It uses a simple and robust circuit that can be implemented in a compact area resulting in a 23% fill-factor for a digital vision sensor in 0.25 μm CMOS technology. An in-built light adaptation mechanism has also been implemented which allows the sensor to better adapt to low-light intensity or to adjust the sensor saturation level. As a consequence, the proposed sensor features a programmable dynamic range. Image lag is eliminated since a reset of the photodetector is performed after the conversion period. A prototype comprising a 32×32 pixel array has been implemented in CMOS 0.25 μm technology. Each pixel occupies an area of 45×45 μm2 with an average power consumption of 85 μW per pixel.

DOI

10.1016/S0026-2692(02)00114-3

 
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Link to publisher version (DOI)

10.1016/S0026-2692(02)00114-3