Removal of block encoding artifacts
AssigneeCorel Corporation
InventorsSergei Nikolacevich Kryukov, Tatyana Olegovna Semenkova, Kryzstof Antoni Zaklika
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Abstract
A method of reducing artifacts in an image previously processed by block transform encoding may comprise the steps of: determining block boundaries; determining an approximate metric of artifact visibility; optionally interpolating across block boundaries; adaptively filtering luminance; optionally adaptively filtering chrominance; adaptively adjusting local saturation variation; and adaptively simulating high spatial frequency image detail; wherein the adaptive steps are executed to an extent or in an amount depending on the metric or standard or measurement of artifact visibility.
Claims18
A method of reducing artifacts in an image previously processed by block transform encoding comprising the steps of:
- determining block boundaries in the image;
- determining an approximate metric of block transform encoding artifact visibility;
- adaptively filtering luminance to a degree dependent on the metric of block transform encoding artifact visibility;
- adaptively adjusting local saturation variation to a degree dependent on the metric of block transform encoding artifact visibility;
- and
- adaptively simulating high spatial frequency image detail to a degree dependent on the metric of block transform encoding artifact visibility.
A method of reducing artifacts in an image previously processed by block transform encoding comprising the steps of:
- determining block boundaries in the image;
- determining an approximate metric of block transforming encoding artifact visibility;
- adaptively filtering luminance with a filter to a degree dependent on the metric of block transform encoding artifact visibility;
- adaptively increasing local chrominance contrast to a degree dependent on the metric of block transform encoding artifact visibility;
- and
- adaptively simulating high frequency image detail by sharpening and adding noise to a degree dependent on the metric of block transform encoding artifact visibility.
A method of reducing artifacts in an image previously processed by block transform encoding comprising:
- determining a block boundary in the image, the block boundary being centered around a center pixel having a chrominance value;
- selecting a median filter window based on luminance texture of pixels within the block boundary;
- and
- replacing the chrominance value of the center pixel with a median chrominance value of pixels within the median filter window.
A computer program storage medium readable by a computer system and encoding a computer program for executing a computer process that reduces artifacts in an image previously processed by block transform encoding, the computer process comprising:
- determining block boundaries in the block transform encoded image;
- determining an approximate metric of block transform encoding artifact visibility;
- adaptively filtering luminance in the block transform encoded image to a degree dependent on the metric of block transform encoding artifact visibility;
- adaptively adjusting local saturation variation in the block transform encoded image to a degree dependent on the metric of block transform encoding artifact visibility;
- and
- adaptively simulating high spatial frequency image detail in the block transform encoded image to a degree dependent on the metric of block transform encoding artifact visibility.
A computer program storage medium readable by a computer system and encoding a computer program for executing a computer process that reduces artifacts in an image previously processed by block transform encoding, the computer process comprising:
- determining block boundaries in the block transform encoded image;
- determining an approximate metric of block transform encoding artifact visibility;
- adaptively filtering luminance in the block transform encoded image with a filter to a degree dependent on the metric of block transform encoding artifact visibility;
- adaptively increasing local chrominance contrast in the block transform encoded image to a degree dependent on the metric of block transform encoding artifact visibility;
- and
- adaptively simulating high frequency image detail in the block transform encoded image to a degree dependent on the metric of block transform encoding artifact visibility by sharpening the block transform encoded image and adding noise to the block transform encoded image.
A computer program storage medium readable by a computer system and encoding a computer program for executing a computer process that reduces artifacts in an image previously processed by block transform encoding, the computer process comprising:
- determining block boundaries in the block transform encoded image;
- adaptively filtering luminance within the block boundaries of the block transform encoded image;
- and
- adaptively adjusting local saturation variation within the block boundaries of the block transform encoded image.
A computer program storage medium readable by a computer system and encoding a computer program for executing a computer process that reduces artifacts in an image previously processed by block transform encoding, the computer process comprising:
- determining a block boundary in the image, the block boundary being centered around a center pixel having a chrominance value;
- selecting a median filter window based on luminance texture of pixels within the block boundary;
- and
- replacing the chrominance value of the center pixel with a median chrominance value of pixels within the median filter window.
Dependencies are inferred from the claim text.