Adaptive filter
AssigneeNokia Mobile Phones Ltd.
InventorsOssi Kalevo, Marta Karczewicz
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Abstract
In order to remove blocking artifacts from a frame which has been coded by blocks and then decoded, a certain number of pixels (n) is selected for examination from both sides of the block boundary (30). The number of pixels selected for examination depends on the image content of the frame in the environment of the block boundary, particularly on the difference of the pixel values across the block boundary (30) and the size of the quantization step of the transformation coefficients used in the transformation coding of the blocks.
Claims13
A method for removing blocking artifacts from a frame of a digital video signal which has been coded by blocks and then decoded, comprising the steps of
- analyzing the image content of the frame in the environment of a block boundary,
- selecting a certain number of pixels for examination from both sides of said block boundary, wherein the number of pixels selected for examination depends on the analyzed image content of the frame in the environment of said block boundary, and
- using filtering to correct the value of at least part of the pixels selected for examination.
A device for removing blocking artifacts from the frame of a digital video signal, which has been coded by blocks and then decoded, comprising
- means for analyzing the image content of a frame,
- means for selecting pixels from the decoded digital video signal for examination and filtering and
- a filter for correcting the value of pixels selected for examination and filtering;
- wherein said means for selecting pixels for examination and filtering are arranged to operate adaptively according to the analyzed image content of the frame.
Dependencies are inferred from the claim text.