Abstract

An image processing method and apparatus for extracting a part of original image data. The mask data to extract a part of original image data is provided as a unit larger than the pixel unit of the original image data. The mask data at the objective position is corrected by use of the mask data at a plurality of positions. A part of the original image data is extracted on the basis of the corrected mask data. The mask data is stored in a memory and corrected on a pixel unit basis of the original image data. Since the mask boundary data is stored into the mask memory, the image converting processes such as enlargement, reduction, rotation, etc. can be performed by use of the mask memory of a small capacity without limiting the mask shape. With this apparatus, the mask image data having the smooth edge portion can be obtained.