Patent ID: 8369639

Claim:
An image processing apparatus comprising: a partitions setting unit that sets up image partitions into which an input image is separated, the input image including pixels; an exclusion pixel determining unit that determines a given pixel to be excluded from setting a number of tones and conversion based upon a predetermined exclusion condition regarding pixel value distribution pattern; a tone number setting unit that sets the number of tones for each of the image partitions set up by the partitions setting unit, based on the gray levels of pixels included in each of the image partitions with the exception of the excluded pixels determined by the determining unit; a conversion unit that converts pixels included in each of the image partitions set up by the partitions setting unit with the exception of the excluded pixels determined by the exclusion pixel determining unit into pixels with tones equal to or less than the number of tones set by the tone number setting unit; and an encoding unit that encodes excluded pixels determined by the exclusion pixel determining unit and pixels converted by the converting unit.