Image processing method and apparatus for suppressing positional shift image degradation

An image processing apparatus comprising:

• a first acquisition unit configured to acquire first image data of an inputted image at a first resolution;
• a storage unit to extract first low-frequency components of luminance values from the first image data, and to store the extracted first low-frequency components in a memory;
• a second acquisition unit configured to acquire second image data of each of divided areas into which the inputted image is divided, said second image data being acquired at a second resolution higher than the first resolution;
• a low-frequency extraction unit to extract second low-frequency components of luminance values from the second image data;
• an image processing unit to perform image processing for the second image data, using both the extracted second low-frequency components and low-frequency components of an area corresponding to the divided area in the inputted image among the first low-frequency components stored in the memory,
• wherein the functions performed by the second acquisition unit, the low-frequency extraction unit, and the image processing unit are performed in sequence for each of the divided areas.

A program stored on a computer-readable medium for causing a computer to execute a processing method comprising:

• a first acquisition procedure of acquiring first image data image of an inputted image at a first resolution;
• a storage procedure of extracting first low-frequency components of luminance values from the first image data, and storing the extracted first low-frequency components in a memory;
• a second acquisition procedure of acquiring second image data of each of divided areas into which the inputted image is divided, said second image data being acquired at a second resolution higher than the first resolution;
• a low-frequency extraction procedure of extracting second low-frequency components of luminance values from the second image data;
• an image processing procedure configured to perform image processing for the second image data, using both the extracted second low-frequency components and low-frequency components of an area corresponding to the divided area in the inputted image among the stored first low-frequency components stored in the memory,
• wherein the second acquisition procedure, the low-frequency extraction procedures and the image processing procedure are performed in sequence for each of the divided areas.