Patent ID: 7428335

Claim:
An image contour extraction method comprising: (a) inputting image data representing an original image and shape data indicating a binary image representing a first provisional shape corresponding to an object in the original image; (b) performing coarse adjustment including: (b1) arranging a plurality of first search reference blocks each having a first size along a contour of the first provisional shape; (b2) reducing the original image, the first provisional shape, and the first search reference blocks in size on the basis of the image data and the shape data to generate a reduced original image, a reduced first provisional shape, and reduced first search reference blocks; (b3) searching, for each of the first search reference blocks, the reduced original image for a first similar block having a texture similar to that of a corresponding one of the reduced first search reference blocks and having a second size larger than the first size; and (b4) replacing all the second search reference blocks with second correction shape blocks obtained by extracting the first similar block from the reduced first provisional shape and reducing the extracted similar block to the first size for each of the first search reference blocks to coarsely bring a contour of the first provisional region close to a contour of the original image; and (c) performing main adjustment including: (c1) restoring the reduced first provisional region to an original size to produce a second provisional region; (c2) arranging a plurality of second search reference blocks each having a third size on a contour of the second provisional region; (c3) searching, for each of the second search reference blocks, the original image for a second similar block having a texture similar to that of a corresponding one of the second search reference blocks and having a fourth larger size than the third size; and (c4) replacing all the second search reference blocks with second correction blocks obtained by extracting the second similar block from the second provisional shape for each of the second search reference blocks to bring a contour of the second provisional shape close to the contour of the original image.