There are provided an image processing apparatus, image processing method and a computer-readable, non-transitory medium that can binarize the input image so that the characters can be differentiated with high accuracy from the background area. The image processing apparatus includes an edge pixel extractor for extracting edge pixels from an input image, a first histogram generator for generating a first histogram based on a luminance value of each of the edge pixels, a second histogram generator for generating a second histogram based on a minimum luminance value among the luminance values of pixels neighboring each of the edge pixels, a static threshold calculator for obtaining a static threshold based on the first histogram and the second histogram, and a binarization unit for binarizing the input image by using the static threshold.