Deblocking filtering
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorsAndrey NORKIN, Kenneth ANDERSSON, Rickard SJÖBERG
Life of this patent
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Abstract
Blocking artifacts at a block boundary between a block and a neighboring block in a video frame are reduced by calculating an offset based on pixel values of pixels in a line of pixels in the block and based on pixel values of pixels in a corresponding line of pixels in the neighboring block. The offset is added to the pixel value of the pixel closest to the block boundary in the line of pixels and is subtracted from the pixel value of the pixel closest to the block boundary in the corresponding line of pixels. The resulting deblocking filter has good low-pass characteristics and is efficient for reducing blocking artifact.
Claims18
A method of reducing blocking artifacts at a block boundary between a block of multiple pixels and a neighboring block of multiple pixels in a video frame, said method comprises:
- calculating a first offset to be equal to (9×(q0−p0)−3×(q1−p1)+8)>>4, wherein >> denotes a right shift operation, p0 denotes a pixel value of a pixel closest to said block boundary in a line of pixels in said block, wherein said line of pixels is perpendicular to said block boundary, p1 denotes a pixel value of a pixel next closest to said block boundary in said line of pixels, q0 denotes a pixel value of a pixel closest to said block boundary in a corresponding line of pixels in said neighboring block, wherein said corresponding line of pixels is perpendicular to said block boundary and q1 denotes a pixel value of a pixel next closest to said block boundary in said corresponding line of pixels;
- modifying said pixel value p0 of said pixel closest to said block boundary in said line of pixels by adding said first offset to said pixel value p0 of said pixel closest to said block boundary in said line of pixels to form a modified pixel value p0′ of said pixel closest to said block boundary in said line of pixels;
- and
- modifying said pixel value q0 of said pixel closest to said block boundary in said corresponding line of pixels by subtracting said first offset from said pixel value q0 of said pixel closest to said block boundary in said corresponding line of pixels to form a modified pixel value q0′ of said pixel closest to said block boundary in said corresponding line of pixels.
A user equipment comprising a deblocking filter unit for reducing blocking artifacts at a block boundary between a block of multiple pixels and a neighboring block of multiple pixels in a video frame, wherein the deblocking filter unit comprises:
- a first offset calculator configured to calculate a first offset to be equal to (9×(q0−p0)−3×)q1−p1)+8)>>4, wherein >> denotes a right shift operation, p0 denotes a pixel value of a pixel closest to said block boundary in a line of pixels in said block, wherein said line of pixels is perpendicular to said block boundary, p1 denotes a pixel value of a pixel next closest to said block boundary in said line of pixels, q0 denotes a pixel value of a pixel closest to said block boundary in a corresponding line of pixels in said neighboring block, wherein said corresponding line of pixels is perpendicular to said block boundary, and q1 denotes a pixel value of a pixel next closest to said block boundary in said corresponding line of pixels;
- and
- a pixel value modifier configured to modify said pixel value p0 of said pixel closest to said block boundary in said line of pixels by adding said first offset to said pixel value p0 of said pixel closest to said block boundary in said line of pixels to form a modified pixel value p0′ of said pixel closest to said block boundary in said line of pixels and to modify said pixel value q0 of said pixel closest to said block boundary in said corresponding line of pixels by subtracting said first offset from said pixel value q0 of said pixel closest to said block boundary in said corresponding line of pixels to form a modified pixel value q0′ of said pixel closest to said block boundary in said corresponding line of pixels.
Dependencies are inferred from the claim text.