An embodiment of an image enhancement method is introduced for use in an electronic device. An image composed of a plurality of pixel values is first received, and each pixel therein is separated into two channels. The image is further divided into a plurality of blocks. A distribution of a selected channel is determined for each block, which is selected from the two channels. For each pixel, the pixel value of the selected channel is adjusted according to at least one distribution corresponding to at least one neighboring block. For each pixel, the pixel value of the other channel is adjusted according to the adjusted pixel value of the selected channel. As a result, the adjusted image is provided.