Retinex Image Processing--Publications--IEEE Trans IP 03/1997
Properties and performance of a center/surround retinex
Daniel J. Jobson, Zia-ur Rahman, and Glenn A. Woodell
IEEE Transactions on Image Processing, Vol. 6, No. 3, March 1997
Abstract
The last version of Edwin Land's retinex model for human vision's
lightness and color constancy has been implemented and tested in image
processing experiments. Previous research has established the
mathematical foundations of Land's retinex but has not subjected his
lightness theory to extensive image processing experiments. 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 the trade-off between rendition and
dynamic range compression that is governed by the surround space
constant. Further, unlike previous results, we find that the placement
of the logarithmic function is important and produces best results when
placed after the surround formation. Also unlike previous results, we
find best rendition for a ``canonical'' gain/offset applied after the
retinex operation. Various functional forms for the retinex surround
are evaluated and a Gaussian form found to perform better than the
inverse square suggested by Land. Images which violate the gray world
assumptions (implicit to the retinex) are investigated to provide
insight into cases where the retinex fails to produce a good rendition.
Retinex Publications Page