This study evaluates the applicability of a retinex type algorithm for digital image processing. Edwin Land developed a number of algorithms based on principles derived from human colour vision and tested them on simulated images. When we tested one of his algorithms on remotely sensed images, it provided some of the expected results, but its effect was not as pronounced as expected.Land used certain thresholding procedures in his algorithm to separate reflectance changes from illumination changes in images. Since the algorithm was developed using carefully controlled simulated scenes, it was not able to cope with the magnitude of natural variability occurring in remotely sensed images. Hence, to adapt Land's procedure for the processing of remotely sensed images, the algorithm concept was refined using adaptive thresholding techniques to include a measure of texture in a neighbourhood as an important decision making factor.
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