An image processing apparatus includes a conversion unit that converts an input image into a plurality of frequency components; a first quantization threshold calculating unit that calculates a first quantization threshold corresponding to a first frequency component among the plurality of frequency components of the input image converted by the conversion unit, based on a statistic value of the first frequency component; a second quantization threshold calculating unit that calculates a second quantization threshold corresponding to a second frequency component other than the first frequency component among the plurality of frequency components, based on the first quantization threshold calculated by the first quantization threshold calculating unit; and a quantization unit that quantizes the first frequency component and the second frequency component by using the first quantization threshold and the second quantization threshold, respectively.