Ponencia
A Mismatch Calibrated Bipolar Spatial Contrast AER Retina with Adjustable Contrast Threshold
Autor/es | Leñero Bardallo, Juan Antonio
Serrano Gotarredona, María Teresa Linares Barranco, Bernabé |
Departamento | Universidad de Sevilla. Departamento de Arquitectura y Tecnología de Computadores |
Fecha de publicación | 2009 |
Fecha de depósito | 2020-09-30 |
Publicado en |
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ISBN/ISSN | 978-1-4244-3827-3 0271-4302 |
Resumen | Address Event Representation (AER) is an emergent
technology for assembling modular multi-blocks
bio-inspired sensory and processing systems. Visual sensors
(retinae) are among the first AER modules to be reported
since ... Address Event Representation (AER) is an emergent technology for assembling modular multi-blocks bio-inspired sensory and processing systems. Visual sensors (retinae) are among the first AER modules to be reported since the introduction of the technology. Spatial contrast AER retinae are of special interest since they provide highly compressed data flow without reducing the relevant information required for performing recognition. Reported AER contrast retinae perform a contrast computation based on the ratio between a pixel’s local light intensity and a spatially weighted average of its neighbourhood. This resulted in compact circuits, but with the penalty of all pixels generating output signals even if they sensed no contrast. In this paper we present a spatial contrast retina with bipolar output: contrast is computed as the relative difference between a pixel’s local light and its weighted spatial average. As a result, contrast includes a sign and the output will be zero if there is no contrast. Furthermore, an adjustable thresholding mechanism has been included, such that pixels remain silent until they sense an absolute contrast above the adjustable threshold. The pixel contrast computation circuit is based on Boahen’s Biharmonic operator contrast circuit, which has been improved to include mismatch calibration and adaptive current based biasing. As a result, the contrast computation circuit shows much less mismatch, is almost insensitive to ambient light illumination, and biasing is much less critical than in the original voltage biasing scheme. A full AER retina version has been submitted for fabrication. In the present paper we provide simulation results. |
Agencias financiadoras | European Union (UE) Ministerio de Educación y Ciencia (MEC). España Junta de Andalucía |
Identificador del proyecto | 216777 (NABAB)
TEC2006-11730-C03-01 P06TIC01417 |
Cita | Leñero Bardallo, J.A., Serrano Gotarredona, M.T. y Linares Barranco, B. (2009). A Mismatch Calibrated Bipolar Spatial Contrast AER Retina with Adjustable Contrast Threshold. En ISCAS 2009: IEEE International Symposium on Circuits and Systems (1493-1496), Taipei, Taiwan: IEEE Computer Society. |
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