Method for noise-robust color changes in digital images
AssigneeGoogle Inc.
InventorNils Kokemohr
Life of this patent
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Abstract
A method for applying filters to digital images with minimal amplification of image noise, comprising filtering the digital image with an EPDR edge-preserving detail-reducing filter, determining a matrix from the filtered image as a result of one or more structure adaptive functions, and modifying the digital image using the filter, adjusted by the matrix values, to produce an enhanced digital image. The order of processing may be inverted, by first determining the matrix and then filtering the matrix with the edge-preserving detail-reducing filter.
Claims20
A computer-implemented method comprising:
- filtering a digital image with an edge-preserving detail-reducing (EPDR) filter, wherein the digital image comprises a plurality of pixels;
- generating a first image by filtering the EPDR-filtered digital image with an image-processing filter that includes a structure-adaptive filter, wherein the structure-adaptive filter provides an intensity of a filter effect on a plurality of pixels of the EPDR-filtered digital image based on a respective geometric distance of each respective pixel of the plurality of pixels of the EPDR-filtered digital image to a reference location in the EPDR-filtered digital image, wherein the reference location is one of a reference pixel and a reference region;
- generating a second image by filtering the EPDR-filtered digital image with a highpass filter;
- and
- producing a third image with a suppressed noise level by adding generated the first image and generated the second image.
A system comprising:
- one or more memory devices;
- one or more processors;
- and
- logic encoded in the one or more memory devices for execution by the one or more processors and when executed operable to perform operations comprising:
- filtering a digital image with an edge-preserving detail-reducing (EPDR) filter, wherein the digital image comprises a plurality of pixels;
- generating a first image by filtering the EPDR-filtered digital image with an image-processing filter that includes a structure-adaptive filter, wherein the structure-adaptive filter is configured to provide an intensity of a filter effect on a plurality of pixels of the EPDR-filtered digital image based on a respective color similarity between a color of each respective pixel of the plurality of pixels of the EPDR-filtered digital image and a reference color of a reference pixel in the EPDR-filtered digital image;
- generating a second image by filtering the EPDR-filtered digital image with a highpass filter;
- and
- producing a third image with a suppressed noise level by adding generated the first image and generated the second image.
A non-transitory computer readable medium having stored thereon program instructions that, when executed by a processor, cause the processor to perform operations including:
- filtering a digital image with an edge-preserving detail-reducing (EPDR) filter, wherein the digital image comprises a plurality of pixels;
- generating a first image by filtering the EPDR-filtered digital image with an image-processing filter that includes a structure-adaptive filter, wherein the structure-adaptive filter provides an intensity of a filter effect on a plurality of pixels of the EPDR-filtered digital image based on a respective geometric distance of the each respective pixel of the plurality of pixels of the EPDR-filtered digital image to a reference pixel in the EPDR-filtered digital image;
- generating a second image by filtering the EPDR-filtered digital image with a highpass filter;
- and
- producing a third image with a suppressed noise level by adding generated the first image and generated the second image.
Dependencies are inferred from the claim text.