Image processing apparatus, image processing method, and image processing system for estimating and correcting color drift between output images

An image processing method performed by an image processing apparatus that reproduces a color of a first output result of original image data by a first image outputting apparatus in a second output result of the original image data by a second image outputting apparatus, the image processing method comprising:

• estimating a first geometric transformation parameter for aligning first output image data with the original image data, the first output image data being acquired by reading the first output result with circuitry of a reading apparatus;
• estimating a second geometric transformation parameter for aligning second output image data with the original image data, the second output image data being acquired by reading the second output result with the circuitry of the reading apparatus;
• associating, based on the first geometric transformation parameter and the second geometric transformation parameter, combinations of color components of the first output image data and the second output image data, which combinations correspond to pixels of the original image data, so as to generate pixel value association data;
• determining, based on a fourth degree polynomial approximation using the pixel value association data, a single mapping for estimating color drift between the first output image data and the second output image data from the original image data;
• and
• subjecting the original image data to color conversion based on the single mapping.