Adaptive filtering based upon boundary strength

• US 20040190626A1
• Filed: 03/11/2004
• Published: 09/30/2004
• Est. Priority Date: 09/14/2001
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Katata, Hiroyuki, Sun, Shijun, Lei, Shawmin
• Application Number:
  US10/799,384
• Publication Number:
  US 20040190626A1
• Time in Patent Office: Days
• US Class Current: 375/240.18
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• 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 19/124 Quantisation
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/15 by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/167 Position within a video image, e.g. region of interest [ROI]
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• CPC Class Codes: H04N 19/197 including determination of the initial value of an encoding parameter H04N19/56 takes precedence
• CPC Class Codes: H04N 19/43 Hardware specially adapted for motion estimation or compensation
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/527 Global motion vector estimation
• CPC Class Codes: H04N 19/573 Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction
• CPC Class Codes: H04N 19/58 Motion compensation with long-term prediction, i.e. the reference frame for a current frame not being the temporally closest one H04N19/23 takes precedence
• CPC Class Codes: H04N 19/60 : using transform coding
• CPC Class Codes: H04N 19/61 : in combination with predictive coding
• CPC Class Codes: H04N 19/615 : using motion compensated temporal filtering [MCTF]
• CPC Class Codes: H04N 19/82 : involving filtering within a prediction loop
• 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

Adjacent regions are identified in an image. Coding parameters for the adjacent regions are identified. Selective filtering is performed at the region between the identified adjacent regions.

Claims

1. A method for at least one of encoding and decoding an image, comprising:

(a) identifying adjacent regions in said image;

(b) identifying coding parameters for said adjacent regions;

(c) identifying transform coefficients for said adjacent regions;

(d) identifying DC components and AC components in said transform coefficients; and

(e) selectively filtering at least a portion of said regions proximate the boundary between said adjacent regions wherein said selectively filtering is based upon a similarity of said DC components and said AC components.

2. A method for at least one of encoding and decoding an image, said method comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions;

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

(d) identifying similarities between coding parameters in a luminance channel of said adjacent regions; and

(e) controlling filtering for both the luminance channel and a chrominance channel in said image according to said similarities.

3. A method for at least one of encoding and decoding an image, said method comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions;

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon whether at least one of said adjacent regions is intra-coded.

4. A method for at least one of encoding and decoding an image, comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions; and

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon whether at least one of said adjacent regions is encoded with residuals.

5. A method for at least one of encoding and decoding an image, comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions; and

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions said filtering based upon determining whether at least two of said adjacent regions are predicted based upon two different reference frames.

6. A method for at least one of encoding and decoding an image, comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions; and

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon determining whether at least two of said adjacent regions have an absolute difference of motion vectors that has a mathematical relationship to a threshold value.

7. The method of claim 6 wherein said absolute difference is in a first direction.

8. The method of claim 7 wherein said absolute difference is also in a second direction different than said first direction.

9. A method for at least one of encoding and decoding an image, comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions; and

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters and wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded.

10. A method for at least one of encoding and decoding an image, comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions; and

(c) selectively filtering at least a portion of said regions proximate the boundary between said adjacent regions based upon said coding parameters, wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded and a second filter when at least one of said adjacent regions is encoded with residuals.

11. A method for at least one of encoding and decoding an image, comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions; and

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

(d) wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded, a second filter when at least one of said adjacent regions is encoded with residuals, and a third filter when said adjacent regions are predicted based upon two different reference frames.

12. A method for at least one of encoding and decoding an image, comprising:

(a) identifying adjacent regions in said image;

(b) examining coding parameters for said adjacent regions; and

(c) selectively filtering at least a portion of said the regions proximate a boundary between said adjacent regions based upon said coding parameters, wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded, a second filter when at least one of said adjacent regions is encoded with residuals, a third filter when at least two of said adjacent regions are predicted based upon two different reference frames, and said third filter when said at least two of said adjacent regions have an absolute difference of motion vectors that falls within a set of values including a threshold value as one extreme.

13. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions;

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

(d) a second identifier for identifying DC and AC components for said adjacent regions; and

(e) a filter controller for controlling said selectively filtering based upon a similarity of said DC and said AC components.

14. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions;

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

(d) a second identifier for identifying similarities between coding parameters in a luminance channel of said adjacent regions; and

(e) a filter controller for controlling said filter wherein said filter is applied to said luminance channel and a chrominance channel based on said similarities.

15. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions;

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering is based upon determining whether at least one of said adjacent regions is intra-coded.

16. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering is based upon determining whether at least one of said adjacent regions is encoded with residuals.

17. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering is based upon determining whether at least two of said adjacent regions are predicted based upon two different reference frames.

18. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering is based upon determining whether at least two of said adjacent regions have an absolute difference of motion vectors that is one of greater than or less than or less than a threshold value.

19. The encoder of claim 18 wherein said absolute difference is also in a first direction.

20. The encoder of claim 19 wherein said absolute difference is also in a second direction different than said first direction.

21. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) at least one filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded.

22. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a plurality of filters for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded and a second filter when said at least one of said adjacent regions is encoded with residuals.

23. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a plurality of filters for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded, a second filter when at least one of said adjacent regions is encoded with residuals, and a third filter when at least two of said adjacent regions are predicted based upon two different reference frames.

24. An encoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a plurality of filters for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded, a second filter when at least one of said adjacent regions is encoded with residuals, a third filter when at least two of said adjacent regions are predicted based upon two different reference frames, and said third filter when at least two of said adjacent regions have an absolute difference of motion vectors that is greater than or less than a threshold value.

25. A decoder for encoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions;

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

(d) a second identifier for identifying DC and AC components for said adjacent regions; and

(e) a filter controller for controlling said selectively filtering based upon a similarity of said DC and said AC components.

26. An decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions;

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

(d) a second identifier for identifying similarities between coding parameters in a luminance channel of said adjacent regions; and

(e) a filter controller for controlling said filter, wherein said filter is applied to said luminance channel and a chrominance channel based on said similarities.

27. A decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering is based upon determining whether at least one of said adjacent regions is intra-coded.

28. A decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering is based upon determining whether at least one of said adjacent regions is encoded with residuals.

29. A decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering is based upon determining whether at least two of said adjacent regions are predicted based upon two different reference frames.

30. A decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner examining coding parameters for said adjacent regions; and

(c) a filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering is based upon determining whether at least two of said adjacent regions have an absolute difference of motion vectors that is greater than or less than a threshold value.

31. The decoder of claim 30 wherein said absolute difference is in a first direction.

32. The decoder of claim 31 wherein said absolute difference is also in a second direction different than said first direction.

33. A decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) at least one filter for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded.

34. A decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a plurality of filters for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded and a second filter when said at least one of said adjacent regions is encoded with residuals.

35. A decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a plurality of filters for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded, a second filter when at least one of said adjacent regions is encoded with residuals, and a third filter when at least two of said adjacent regions are predicted based upon two different reference frames.

36. A decoder for decoding an image comprising:

(a) a first identifier for identifying adjacent regions in said image;

(b) an examiner for examining coding parameters for said adjacent regions; and

(c) a plurality of filters for selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

wherein said selectively filtering uses a first filter when said adjacent regions are intra-coded, a second filter when at least one of said adjacent regions is encoded with residuals, a third filter when at least two of said adjacent regions are predicted based upon two different reference frames, and said third filter when said at least two of said adjacent regions have an absolute difference of motion vectors that is a greater than or less than a threshold value.

37. A computer readable medium comprising instructions for performing the acts of:

(a) identifying adjacent regions in an image;

(b) examining coding parameters for said adjacent regions;

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

(d) identifying similarities between said coding parameters in a luminance channel of said adjacent regions; and

(e) controlling filtering for both the luminance channel and a chrominance channel in said image according to said similarities in the luminance channel.

38. A computer data signal embodied in an electronic transmission, said signal comprising instructions for:

(a) identifying adjacent regions in an image;

(b) examining coding parameters for said adjacent regions;

(c) selectively filtering at least a portion of said regions proximate a boundary between said adjacent regions based upon said coding parameters;

(d) identifying similarities between said coding parameters in a luminance channel of said adjacent regions; and

(e) controlling filtering for both the luminance channel and a chrominance channel in said image according to said similarities in the luminance channel.