Method and apparatus for image sharpening using edge-preserving filters

An electronic device, comprising:

• a processor;
• and
• a non-transitory computer readable storage medium storing instructions that, when executed, cause the processor to:
• receive an input image;
• apply low pass filtering to the input image to generate a first image and a second image, wherein a kernel size of the first image and the second image are different;
• apply edge preserving filtering to the input image to generate a third image and a fourth image, wherein a kernel size of the third image and the fourth image are different;
• subtract the first image from the third image to obtain a first resulting image, wherein the first image has a larger kernel size than the third image;
• subtract the second image from the fourth image to obtain a second resulting image, wherein the second image has a larger kernel size than the fourth image;
• and
• sum the first resultant image, the second resultant image, and the input image to generate a sharpened image.

An image processor of an electronic comprising:

• a medium low pass filter that applies low pass filtering to an input image to obtain a first moderately-blurred image;
• a wide low pass filter that applies low pass filtering to the input image to obtain a highly-blurred image;
• an edge-preserving narrow filter that applies edge-preserving filtering to the input image to obtain a slightly-blurred image;
• an edge-preserving medium filter that applies edge-preserving filtering to the input image to obtain a second moderately-blurred image;
• a first combiner that subtracts the first moderately-blurred image from the slightly-blurred image to obtain a medium sharp image;
• a second combiner that subtracts the highly-blurred image from the second moderately-blurred image to obtain a wide sharp image;
• and
• a third combiner that sums the medium sharp image, the wide sharp image, and the input image to obtain a sharpened image.