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Investigations of analog VLSI visual transduction and motion processing


Delbruck, Tobias (1993) Investigations of analog VLSI visual transduction and motion processing. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/N5TD-G224.


This thesis is a detailed description of a neuromorphic visual-motion processing chip and its component parts. The chip is the first two-dimensional silicon retina with a full set of direction-selective, velocity-tuned pixels. The architecture for the chip is based on the biological correlation-type motion detector, with the addition of a novel spatiotemporal aggregation. All the processing on the chip is analog and occurs in parallel. Novel, on-chip, continuous-time, adaptive, logarithmic photoreceptor circuits are used to couple temporal image signals into the motion processing network. These continuous-time photoreceptor circuits have also been used in a wide variety of other vision chips. The photoreceptor circuits center their operating point around the history of the illumination, simultaneously achieving high sensitivity and wide dynamic range. The receptor circuits are characterized and analyzed carefully for their temporal bandwidth and detection performance. Noise properties are analyzed, resulting in a simple and intuitive understanding of the limiting parameters. Novel adaptive elements are described that are insensitive to light-generated minority carriers. Novel measurements are presented of the spectral response properties of phototransducers that can be built in ordinary CMOS or BiCMOS processes. A novel nonlinear circuit that measures similarity and dissimilarity of signals is described and characterized. These bump circuits are used on the motion chip to extract the motion energy signal, and have also been used in other chips in numerous ways.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Computation and Neural Systems)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Computation and Neural Systems
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Mead, Carver
Thesis Committee:
  • Koch, Christof (chair)
  • Mead, Carver
  • Perona, Pietro
  • Goodman, Rodney M.
  • Fraser, Scott E.
Defense Date:4 November 1992
Record Number:CaltechETD:etd-07022004-144710
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2803
Deposited By: Imported from ETD-db
Deposited On:02 Jul 2004
Last Modified:31 Aug 2022 00:18

Thesis Files

PDF (tobithesis.pdf) - Final Version
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