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Spatial Filtering in Tone Reproduction and Vision


Moore, Andrew John (1992) Spatial Filtering in Tone Reproduction and Vision. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/YVBY-QN45.


This thesis is concerned with spatial filtering. What is its utility in tone reproduction? Does it exist in vision, and if so, what constraints does it impose on the nervous system?

Tone reproduction is just the art and science of taking a picture and then displaying it. The sensors available to capture an image have a greater dynamic range than the media that may be used to display it. Conventionally, spatial filtering is used to boost contrast; it ameliorates the loss of contrast that results when the sensor signal range is scaled down to fit the display range. In this thesis, a type of nonlinear spatial filtering is discussed that results in direct range reduction without range scaling. This filtering process is instantiated in a real-time image processor built using analog CMOS VLSI.

Spatial filtering must be applied with care in both artificial and natural vision systems. It is argued that the nervous system does not simply filter linearly across an image. Rather, the way that we see things implies that the nervous system filters nonlinearly. Further, many models for color vision include a high-pass filtering step in which the DC information is lost. A real-time study of filtering in color space leads to the conclusion that the nervous system is not that simple, and that it maintains DC information by referencing to white.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Analog VLSI, neural networks, Retinex, retina, neuroscience, vision, video, high dynamic range
Degree Grantor:California Institute of Technology
Major Option:Computation and Neural Systems
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Goodman, Rodney M.
Thesis Committee:
  • Goodman, Rodney M. (chair)
  • Van Essen, David C.
  • Allman, John Morgan
  • Mead, Carver
  • Koch, Christof
Defense Date:11 May 1992
Non-Caltech Author Email:amoore2004 AT
Record Number:CaltechTHESIS:04112013-082009623
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7608
Deposited By: Benjamin Perez
Deposited On:11 Apr 2013 15:33
Last Modified:03 Nov 2021 23:08

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