Fuzzy enhancement method using logarithmic models

Simple and efficient enhancement methods can be obtained if affine transforms within logarithmic models are used. A very important thing in the affine transform determination for color images is the coordinate system that is used for color space representation. Thus, the using of the RGB coordinates leads to a simultaneous modification of luminosity and saturation. In this paper using a 4-coordinate color system called lrgb, one can define affine transforms, which allow a separated modification of luminosity l and saturation s (saturation being calculated with the component rgb in the chromatic plane). Better results can be obtained if fuzzy partitions are defined on the image support and then the pixels are separately processed in each window belonging to the defined partition. Their elements will be fuzzy windows and in each of them there will be defined an affine transform induced by parameters using the fuzzy mean, fuzzy variance and fuzzy saturation computed for the pixels that belong to the analyzed window. The final image is obtained by replacing the three affine transform parameters with three fuzzy surfaces.