Post-process filter for decompressed screen content

Patent metadata

Field	Value
Publication number	US-9386319-B2
Application number	US-201314019436-A
Country	US
Kind code	B2
Filing date	Sep 5, 2013
Priority date	Sep 5, 2013
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

Methods and systems for processing graphical data received at a computing system from a remote source are described. One method includes decoding received graphical content, the received graphical content including an image being compressed using a plurality of codecs, wherein decoding the received graphical content includes creating a decoded image. The method also includes, based on quality of the received graphical content, selecting from among a plurality of filters to apply to the decoded image. The method further includes applying a plurality of filters to at least a portion of the decoded image.

First claim

The invention claimed is:

1. A method of processing graphical data received at a computing system from a remote source, the method comprising:
decoding received graphical content, the received graphical content including an image being compressed using a plurality of codecs, wherein decoding the received graphical content includes creating a decoded image including a plurality of image blocks and a plurality of regions, each region independently associated with one of the plurality of codecs;
for each image block of the plurality of image blocks that includes a region associated with a lossy codec:
determining a quality factor, corresponding to an amount of loss of data due to compression, for the image block;
detecting partitions between the image block and adjacent image blocks based on boundaries between regions in the screen image;
based on the quality factor of the received graphical content in the image block, selecting from among a plurality of filters to apply to the image block; and
applying one or more filters of the plurality of filters to the image block.

2. The method of claim 1 , wherein the plurality of filters includes one or more of a deblocking filter, a bilateral filter, and a peaking filter.

3. The method of claim 1 , wherein, for at least one of the plurality of regions encoded using a lossless codec, no filter is applied.

4. The method of claim 1 , wherein the plurality of filters includes an asymmetric deblocking filter.

5. The method of claim 1 , wherein the method includes, for a first image block of the plurality of image blocks including a region having a compression within a first threshold, applying a plurality of filters to the first image block in a first order and, for a second image block of the plurality of image blocks including a region having a compression within a second threshold, applying the plurality of filters in a second order, the second threshold different from the first threshold and the second order different from the first order.

6. The method of claim 5 , wherein the first threshold is provided by a first codec providing a high compression rate, and the second threshold is provided by a second codec providing a medium compression rate.

7. The method of claim 6 , wherein the first order comprises sequentially applying a deblocking filter, a bilateral filter, and a peaking filter, and wherein the second order comprises sequentially applying a deblocking filter, a peaking filter, and a bilateral filter.

8. The method of claim 7 , wherein in the first order a first set of filter parameters are applied by the bilateral filter, and in the second order a second set of filter parameters are applied by the bilateral filter.

9. The method of claim 7 , wherein in the first order a first set of filter parameters are applied by the peaking filter and in the second order a second set of filter parameters are applied by the peaking filter.

10. The method of claim 6 , wherein the first and second thresholds are defined in a table of quantization parameters (QP).

11. The method of claim 1 , further comprising encoding and transmitting graphical content from the remote source to the computing system, thereby providing received graphical content at the computing system.

12. The method of claim 11 , further comprising applying a deblocking filter to the graphical content at the remote source prior to encoding and transmitting the graphical data.

13. A computing system comprising:
a programmable circuit;
a display;
a memory operatively connected to the programmable circuit and storing program instructions which, when executed by the programmable circuit, perform a method of processing graphical data from a remote source for output to the display, the method comprising:
decoding received graphical content, the received graphical content including an image compressed using a plurality of codecs, wherein decoding the received graphical content includes creating a decoded image including a plurality of image blocks and a plurality of regions, each region independently associated with one of the plurality of codecs;
for each image block of the plurality of image blocks that includes a region associated with a lossy codec:
determining a quality factor, corresponding to an amount of loss of data due to compression, for the image block;
detecting partitions between the image block and adjacent image blocks based on boundaries between regions in the screen image;
based on the quality factor of the received graphical content in the image block, selecting from among a plurality of filters to apply to the image block; and
applying one or more filters of the plurality of filters to the image block, the one or more filters including an asymmetric deblocking filter.

14. The computing system of claim 13 , where each region has an associated content type and codec selected from among the plurality of codecs.

15. The computing system of claim 14 , wherein the associated content type is at least one of a text type, an image type, and a video type.

16. The computing system of claim 13 , wherein the asymmetric deblocking filter includes a plurality of filter taps, wherein the plurality of filter taps are disposed across an image region in an unbalanced arrangement around a center point.

17. The computing system of claim 13 , wherein the one or more filters further includes a peaking filter and a bilateral filter, wherein the peaking filter is categorized by the following equation:

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Assignees

• Microsoft Technology Licensing Llc

Inventors

• Zhu Lihua
• Sankuratri Sridhar
• Dube Arjun
• Kumar B Anil
• Abdo Nadim

Classifications

• H04N19/44 Primary

  Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder · CPC title

• H04N19/136

  Incoming video signal characteristics or properties · CPC title

• H04N19/182

  the unit being a pixel · CPC title

• H04N19/86

  involving reduction of coding artifacts, e.g. of blockiness · CPC title

• H04N19/117

  Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635) · CPC title