1. A method for processing images in an electronic system, comprising: mapping multiple pixel sets of an image to a color space that includes a color sub-space and a luminance sub-space, the color sub-space substantially associating to visible light frequencies; classifying the multiple pixel sets into at least a first type of pixel sets and a second type of pixel sets according to a feature of the multiple pixels in the color-subspace; generating a first statistic distribution for the first type of pixel sets over corresponding visible light frequencies of the first type of pixel sets; generating a second statistic distribution for the second type of pixel sets over corresponding luminance values of the second type of pixel sets; joining the first type of pixel sets and the second type of pixels respectively to generate multiple pixel blocks; and performing a continued processing to the image using the multiple blocks.