| CPC G06T 5/70 (2024.01) [G06T 5/10 (2013.01); G06T 2207/20056 (2013.01)] | 20 Claims |
|
1. A method comprising:
receiving an input image from an image capturing device;
filtering the received input image by applying a discrete cosine transform based noise filtering (DCT-NF) process, the DCT-NF process comprising:
converting the input image from an original space into a perceptual space by applying a gamma correction to generate a gamma-corrected image;
separating a luminance channel from chroma channels of the input image or the gamma-corrected image to generate a luminance image composed of the luminance channel and chrominance images composed of the chroma channels, respectively;
dividing the luminance image into overlapping patches, each patch being a different partial portion of the luminance image, wherein the overlapping patches include a first grid of patches that at least partially overlaps a second grid of patches;
computing a discrete cosine transform (DCT) of the overlapping patches;
among the overlapping patches, suppressing patches that include an input DCT coefficient within a threshold range;
applying an inverse discrete cosine transform (IDCT) to the suppressed patches and to remaining overlapping patches that include an input DCT coefficient outside of the threshold range to generate IDCT-transformed patches;
combining a luminance channel of the IDCT-transformed patches and the chrominance images to form a color image; and
generating a DCT noise-filtered output image by applying an inverse gamma correction to convert the color image to the original space; and
outputting the DCT noise-filtered output image;
wherein the second grid of patches covers a different portion of the luminance image than the first grid of patches such that (i) the first grid of patches covers part of the luminance image not covered by the second grid of patches and (ii) the second grid of patches includes an empty portion not covering any portion of the luminance image.
|