Departmental Papers (BE)

Document Type

Journal Article

Date of this Version

February 2003

Comments

Copyright 2003 IEEE. Reprinted from IEEE Journal of Solid-State Circuits, Volume 38, Issue 2, February 2003, pages 281-294.
Publisher URL: http://ieeexplore.ieee.org/xpl/tocresult.jsp?isNumber=26391&puNumber=4

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Abstract

An arbitrated address-event imager has been designed and fabricated in a 0.6-μm CMOS process. The imager is composed of 80 x 60 pixels of 32 x 30 μm. The value of the light intensity collected by each photosensitive element is inversely proportional to the pixel’s interspike time interval. The readout of each spike is initiated by the individual pixel; therefore, the available output bandwidth is allocated according to pixel output demand. This encoding of light intensities favors brighter pixels, equalizes the number of integrated photons across light intensity, and minimizes power consumption. Tests conducted on the imager showed a large output dynamic range of 180 dB (under bright local illumination) for an individual pixel. The array, on the other hand, produced a dynamic range of 120 dB (under uniform bright illumination and when no lower bound was placed on the update rate per pixel). The dynamic range is 48.9 dB value at 30-pixel updates/s. Power consumption is 3.4 mW in uniform indoor light and a mean event rate of 200 kHz, which updates each pixel 41.6 times per second. The imager is capable of updating each pixel 8.3K times per second (under bright local illumination).

Keywords

arbitrated, address event, digital image sensor, high dynamic range, low-power imager

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Date Posted: 10 November 2004

This document has been peer reviewed.