Retinex Image Processing--Publications--NASA TM 110188
Conference
PROPERTIES OF A CENTER/SURROUND RETINEX PART TWO:
SURROUND DESIGN
Daniel J. Jobson, and Glenn A. Woodell
Abstract
The last version of Edwin Land's retinex model for human vision's
lightness and color constancy has been implemented. Previous research
has established the mathematical foundations of Land's retinex but has
not examined specific design issues and their effects on the properties
of the retinex operation. We have sought to define a practical
implementation of the retinex without particular concern for its
validity as a model for human lightness and color perception. Here we
describe issues involved in designing the surround function. We find
that there is a trade-off between rendition and dynamic range
compression that is governed by the surround space constant. Various
functional forms for the retinex surround are evaluated and a Gaussian
form found to perform better than the inverse square suggested by Land.
Preliminary testing led to the design of a Gaussian surround with a
space constant of 80 pixels as a reasonable compromise between dynamic
range compression and rendition.
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