Patent ID: 8326032

Claim:
An image processing apparatus that performs an error diffusion process on M-value image data by using a predetermined error weight matrix to quantize the M-value image data into N-value image data (M>N>1) for each predetermined color component, the image processing apparatus comprising: a corrected-value calculating unit that calculates a corrected value by adding a first value and a second value to a pixel value corresponding to a processing-target color component of a pixel of interest of the M-value image data, the first value being obtained by multiplying an error for each quantized pixel of the processing-target color component by the error weight matrix, and the second value being obtained by multiplying an error for each quantized pixel of a different color component from the processing-target color component by the error weight matrix; a quantizing unit that compares the corrected value with a quantization threshold corresponding to the N-value image data, and outputs N-value image data of the processing-target color component; and an error diffusion unit that calculates, as an error at the pixel of interest, a value by subtracting a quantization threshold corresponding to the output N-value image data from a value which is obtained by adding the first value to the pixel value corresponding to the processing-target color component of the pixel of interest.