Image restoration system, image restoration method, and image restoration program

An image restoration method comprising:

• estimating a pixel value which each pixel in a defect region as a region to be restored in an image may take, based on a pixel value of pixels in a non-defect region as a region in the image not including the defect region;
• selecting a pair of patches in which a defect patch and a reference patch are most similar to each other from among the pairs of patches including the defect patch as an image of a region including the defect region and the reference patch as an image of a region not including the defect region;
• wherein a patch selection function is expressed as a product or sum of at least two types of functions, one type of function is a function which takes a smaller value as a luminance gradient of the defect patch candidate is larger, and another type of function is a function which takes a smaller value as the image of the defect patch candidate and the image of the reference patch candidate are more similar to each other, and when selecting the pair of patches, selecting a pair of patches having smaller value of the patch selection function as a pair of patches to be restored, based on a relationship between an estimated pixel value of a defect region in the defect patch and a pixel value of the corresponding reference patch;
• and
• restoring the defect patch based on the reference patch in the selected pair of patches.

A non-transitory computer readable information recording medium storing an image restoration program, when executed by a processor, performs a method for:

• estimating a pixel value which each pixel in a defect region as a region to be restored in an image may take, based on a pixel value of pixels in a non-defect region as a region in the image not including the defect region;
• selecting a pair of patches in which a defect patch and a reference patch are most similar to each other from among the pairs of patches including the defect patch as an image of a region including the defect region and the reference patch as an image of a region not including the defect region;
• wherein a patch selection function is expressed as a product or sum of at least two types of functions, one type of function is a function which takes a smaller value as a luminance gradient of the defect patch candidate is larger, and another type of function is a function which takes a smaller value as the image of the defect patch candidate and the image of the reference patch candidate are more similar to each other, and when selecting the pair of patches, selecting a pair of patches having smaller value of the patch selection function as a pair of patches to be restored, based on a relationship between an estimated pixel value of a defect region in the defect patch and a pixel value of the corresponding reference patch;
• and
• restoring the defect patch based on the reference patch in the selected pair of patches.