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A contrast retina with on-chip calibration for neuromorphic spike-based AER vision systems (2007)
| Venue: | IEEE Trans. on Circuits and Systems-I |
| Citations: | 19 - 7 self |
BibTeX
@ARTICLE{Costas-santos07acontrast,
author = {Jesús Costas-santos and Teresa Serrano-gotarredona and Rafael Serrano-gotarredona and Bernabé Linares-barranco},
title = {A contrast retina with on-chip calibration for neuromorphic spike-based AER vision systems},
journal = {IEEE Trans. on Circuits and Systems-I},
year = {2007},
volume = {54},
pages = {2006}
}
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Abstract
Abstract—We present a 32 32 pixels contrast retina microchip that provides its output as an address event representation (AER) stream. Spatial contrast is computed as the ratio between pixel photocurrent and a local average between neighboring pixels obtained with a diffuser network. This current-based computation produces an important amount of mismatch between neighboring pixels, because the currents can be as low as a few pico-amperes. Consequently, a compact calibration circuitry has been included to trimm each pixel. Measurements show a reduction in mismatch standard deviation from 57 % to 6.6 % (indoor light). The paper describes the design of the pixel with its spatial contrast computation and calibration sections. About one third of pixel area is used for a 5-bit calibration circuit. Area of pixel is SV m ST m, while its current consumption is about 20 nA at 1-kHz event rate. Extensive experimental results are provided for a prototype fabricated in a standard 0.35- m CMOS process. Index Terms—Address-event representation (AER), analog circuits, artifical retina, calibration, contrast computation, currentmode circuits, imagers, low-power circuits and systems, mismatch, neuromorphic circuits, sensory systems, trimming, vision systems, weak inversion circuits. I.
Keyphrases
neuromorphic spike-based aer vision system contrast retina on-chip calibration 5-bit calibration circuit analog circuit 1-khz event rate mismatch standard deviation weak inversion circuit index term address-event representation spatial contrast computation low-power circuit contrast computation current-based computation important amount address event representation compact calibration circuitry local average calibration section vision system pixel photocurrent spatial contrast pixel area neuromorphic circuit indoor light current consumption extensive experimental result currentmode circuit cmos process artifical retina retina microchip sv st diffuser network sensory system
