Functions optimization of Lab-contrast graded transformation

The purpose of this study is to create algorithm for custom conversion of contrast distribution on stepped-tone scales. The idea is to find suitable Lab-contrast distribution, keeping in mind that scaled distortion of digital representation of pixels would keep the real perception of color contrast all the same, if only less bright. In order to approximately calculate the function of Lab-contrast gradual conversion, this study considers two families of parametric algorithms, the first one uses subset of pixels on the scale as parameters, while the another one uses many gradations as they are. The problem of selecting the set of optimal parameters is solved by comparison of range of calculation errors achieved on a set of typical examples by the function of Lab-contrast distribution on stepped-tone scales. The study shows the function of Lab-contrast distribution on stepped-tone scales that gives the least error and provides example that proves that with optimal set of parameters chosen, it is not only possible to avoid visual distortion but the details can also be improved. These findings may be useful in management of maps of RGB-color images for PC peripherals in order to improve perceptive quality of details.