Patent ID: 7884969

Claim:
An image processing apparatus which, in performing quantization processing on image data representing a gradation value of each pixel, uses an error diffusion method that distributes error data of a pixel of interest to neighboring pixels around the pixel of interest, the error data being generated by quantizing the pixel of interest, the apparatus comprising: a first conversion unit that, when an error value represented by the error data is a particular value, converts the error data into compressed error data with a data volume less than that of the original error data; a first recovering unit that recovers the original error data representing the particular error value from the compressed error data; a second conversion unit that, when an error value represented by the error data is not the particular value, attaches a second identifier to the error data; and a second recovering unit that recovers the error data representing the error value other than the particular error value by removing the second identifier from the error data that has been attached with the second identifier.