A method, apparatus, system, and program for image processing are provided to perform operations of recognizing, reproducing, and enhancing an image, particularly one having character, symbol, or line-segment portions. An image obtainer obtains a multivalue image of color or grayscale. A brightness image generator generates a brightness image of the multivalue image, representing brightness values of respective pixels of the multivalue image. A topographic feature image generator generates a topographic feature image of the multivalue image, having a topographic feature corresponding to the brightness values. A topographic feature adder generates a binary image of the multivalue image, by using information contained in the topographic feature.