Video deblocking method and apparatus

• US 6,922,492 B2
• Filed: 12/27/2002
• Issued: 07/26/2005
• Est. Priority Date: 12/27/2002
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Zhang, Jian, Yu, Zhenghua
• Primary Examiner(s): Boudreau, Leo
• Assistant Examiner(s): SHERALI, ISHRAT I
• Application Number:
  US10/330,388
• Publication Number:
  US 20040126034A1
• Time in Patent Office: 942 Days
• Field of Search: 382/166, 382/254, 382/261, 382/266, 382/268, 382/275, 382/251, 382/248, 382232-233, 382260-269, 37524024-24025, 375/240.03, 375/240.02, 375/240.2, 375/240.01, 375/240.11, 375/240.12, 375/240.29, 375/240.27, 358/426.14, 341/94
• US Class Current: 382/260
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression
• CPC Class Codes: H04N 19/86 involving reduction of coding artifacts, e.g. of blockiness

Abstract

Digital video imagery is deblocked as a function of horizontal and/or vertically oriented pixels that share a common attribute (such as a corresponding pixel value). In particular, a deblocking filter can be selected from amongst a plurality of candidate deblocking filters as a function of the presence of pixels that are both adjacent to one another and that are substantially similar to one another. The selected deblocking filter can be applied as a function, at least in part, of a respective center of the pixels that are both adjacent and similar to one another. In one embodiment, luminance information is deblocked pursuant to a process that is different from a deblocking process that is used with chrominance information.

Claims

1. A method comprising:

providing a plurality of decoded video information comprising a plurality of pixels;

comparing pixels from amongst the plurality of pixels having a predetermined spatial relationship to one another to identify at least one group of pixels that share a common attribute;

selecting a deblocking filter based, at least in part, upon the at least one group of pixels that share a common attribute;

applying the deblocking filter as a function of a respective center of at least one group of pixels within the at least one group of pixels.

2. The method of claim 1 wherein comparing pixels from amongst the plurality of pixels having a predetermined spatial relationship to one another includes comparing pixels from amongst the plurality of pixels that are adjacent to one another.

3. The method of claim 2 wherein comparing pixels from amongst the plurality of pixels that are adjacent to one another includes at least one of:

comparing pixels from amongst the plurality of pixels that are horizontally adjacent to one another; and

comparing pixels from amongst the plurality of pixels that are vertically adjacent to one another.

4. The method of claim 1 wherein comparing pixels from amongst the plurality of pixels having a predetermined spatial relationship to one another to identify at least one group of pixels that share a common attribute includes comparing pixels from amongst the plurality of pixels having a predetermined spatial relationship to one another to identify pairs of pixels that are substantially similar to one another.

5. The method of claim 1 wherein comparing pixels from amongst the plurality of pixels having a predetermined spatial relationship to one another to identify at least one group of pixels that share a common attribute includes locating the respective center of at least one group of pixels within the at least one group of pixels to apply deblocklng filters based, at least in part on the common attribute.

6. The method of claim 1 wherein selecting a deblocking filter includes selecting a deblocking filter from amongst a plurality of deblocking filters.

7. The method of claim 6 wherein selecting a deblocking filter from amongst a plurality of deblocking filters includes selecting a deblocking filter from amongst a plurality of deblocking filters that include at least:

a strong filter that will affect a majority of the pixels as are contained within a specific grouping of the pixels; and

a weak filter that will affect only a minority of the pixels as are contained within the specific grouping of the pixels.

8. The method of claim 1 wherein applying the deblocking filter as a function of the respective center includes applying the deblocking filter bilaterally symmetrical with respect to the respective center.

9. The method of claim 1 wherein applying the deblocking filter as a function of the respective center includes applying the deblocking filter bilaterally non-symmetrical with respect to the respective center.

10. A method for deblocking decoded video information that includes luminance information and chrominance information, comprising:

deblocking the luminance information pursuant to a first deblocking process; and

deblocking the chrominance information using a deblocking process other than the first deblocking process;

wherein deblocking the luminance information pursuant to the first deblocking process includes;

comparing pixels from amongst a block of pixels having a predetermined spatial relationship to one another to identify at least one group of pixels that share a common attribute;

selecting a deblocking filter based, at least in part, upon the at least one group of pixels that share a common attribute;

applying the deblocking filter as a function of a respective center of at least one group of pixels within the at least one group of pixels.

11. The method of claim 10 wherein comparing pixels from amongst the block of pixels having a predetermined spatial relationship to one another includes comparing pixels from amongst the block of pixels that are adjacent to one another.

12. The method of claim 11 wherein comparing pixels from amongst the block of pixels that are adjacent to one another includes at least one of:

comparing pixels from amongst the block of pixels that are horizontally adjacent to one another; and

comparing pixels from amongst the block of pixels that are vertically adjacent to one another.

13. The method of claim 11 wherein comparing pixels from amongst the block of pixels that are adjacent to one another to identify at least one group of pixels that share a common attribute includes comparing pixels from amongst the block of pixels that are adjacent to one another to identify pairs of pixels that are substantially similar to one another.

14. The method of claim 10 wherein comparing pixels from amongst a block of pixels having a predetermined spatial relationship to one another to identify at least one group of pixels that share a common attribute includes locating the respective center of at least one group of pixels to apply deblocking filters based, at least in part, on the common attribute.

15. The method of claim 13 wherein selecting a filter includes selecting a deblocking filter from amongst a plurality of deblocking filters.

16. The method of claim 15 wherein selecting a deblocking filter from amongst a plurality of deblocking filters includes selecting a deblocking filter from amongst a plurality of deblocking filters that include at least:

a strong filter that will affect a majority of the pixels as are contained within a specific grouping of the pixels; and

a weak filter that will affect only a minority of the pixels as are contained within the specific grouping of the pixels.

17. The method of claim 10 wherein applying the deblocking filter as a function of the respective center includes applying the deblocking filter bilaterally symmetrical with respect to the respective center.

18. The method of claim 10 wherein applying the deblocking filter as a function of the respective center includes applying the deblocking filter bilaterally non-symmetrical with respect to the respective center.

19. An apparatus comprising:

a decoded video data input;

an adjacent similar pixel detector having an input operably coupled to the decoded video data input and having an adjacent similar pixel count output and a similar pixel section count output;

a deblocking filter selector that is responsive to the adjacent similar pixel count output and the similar pixel section count output and having a deblocking filter selection output; and

a plurality of deblocking filters responsive to the deblocking filter selection output.

20. The apparatus of claim 19 and further comprising a video decoder having a decoded video data output that is operably coupled to the decoded video data input.

21. The apparatus of claim 19 and further comprising a display that is operably coupled to at least one of the plurality of deblocking filters.

22. The apparatus of claim 19 wherein the plurality of deblocking filters includes at least one strong filter that will affect a majority of pixels as are contained within a specific grouping of pixels and at least one weak filter that will affect only a minority of the pixels as are contained within the specific grouping of the pixels.

23. The apparatus of claim 19 wherein the plurality of deblocking filters includes at least four deblocking filters.

24. The apparatus of claim 19 wherein the plurality of deblocking filters includes at least one bilaterally symmetrical filter and at least one bilaterally non-symmetrical filter.