1. An image enhancement method for improving color perception of colorblind viewers comprising: an image input step being inputting a normal image as perceived by a person with normal color perception and inputting a colorblindness-simulative image as perceived by a colorblind person; an image difference area analyzing step being distinguishing difference between the normal image and the colorblindness-simulative image; wherein the difference is converted into a difference image; an image color distribution adjusting step and having a color channel equalizing step being equalizing and enhancing R, G and B channel images of the difference image; wherein the difference image is converted into an equalized image; a difference removing step being converting the equalized image to a colorblindness-optimized image for a colorblind person so that color vision obtained by a colorblind person from the colorblindness-optimized image is substantially identical to that obtained by a person with normal color perception from the normal image; and an image output step being outputting the colorblindness-optimized image.