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1. WO2011007586 - METHODS AND SYSTEMS FOR REDUCING COMPRESSION ARTIFACTS

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

CLAIMS

1. A system for removing artifacts from a digital image, said system comprising:

a) a motion analyzer for determining a motion indicator associated with a pixel location in said digital image;

b) an edge analyzer for determining an edge-strength indicator associated with said pixel location in said digital image; and

c) a combiner for combining said motion indicator and said edge-strength indicator to effectuate filtering at said pixel location, wherein said filtering at said pixel location is based on said combination.

2. The system as described in claim 1 , wherein said filtering at said pixel location comprises a bilateral filter.

3. The system as described in claim 2 , wherein said edge analyzer comprises a range-kernel adder for summing a range kernel associated with said bilateral filter at said pixel location.

4. The system as described in claim 1 , wherein said edge analyzer comprises :

a) an edge detector for associating an edge-strength value with each pixel location in a first plurality of pixel locations proximate to said pixel location in said digital image; and

b) an edge-strength-indicator associator for associating averaged edge-strength values with said pixel location.

5. The system as described in claim 4, wherein said first plurality of pixel locations are determined based on a transform size associated with a compression method associated with said digital image .

6. The system as described in claim 1 , wherein said filtering at said pixel location comprises a first filter associated with a first set of filter parameter values .

7. The system as described in claim 6, wherein said first set of filter parameter values are based on said combination.

8. The system as described in claim 6, wherein said first filter is a filter selected from the group consisting of a two-dimensional bilateral filter, a three-dimensional bilateral filter, a spatial-only filter and a spatio-temporal filter.

9. The system as described in claim 1 , wherein said motion analyzer comprises a motion estimator for measuring, between said digital image and a temporally neighboring image, a spatial displacement associated with said pixel location.

10. The system as described in claim 1 , wherein said motion analyzer comprises a motion detector for detecting, between said digital image and a temporally neighboring image, a likelihood of motion associated with said pixel location.

1 1 . The system as described in claim 1 , wherein said edge analyzer comprises an edge detector.

12. The system as described in claim 1 1 , wherein said edge detector is an edge detector selected from the group consisting of a Canny edge detector, a Sobel edge detector, a Roberts Cross edge detector, a Prewitt edge detector, a Rothwell edge detector, a Laplacian-of-Gaussian edge detector and a Laplace edge detector.

13. The system as described in claim 1 , wherein said filtering at said pixel location comprises a first filtering at said pixel location when said combination meets a first criterion and a second filtering at said pixel location when said combination does not meet said first criterion.

14. The system as described in claim 13 , wherein:

a) said first filtering comprises a first filter associated with a first set of filter parameter values; and

b) said second filtering comprises said first filter associated with a second set of filter parameter values.

15. The system as described in claim 14 , wherein said first filter is a filter selected from the group consisting of a two-dimensional bilateral filter, a three-dimensional bilateral filter, a spatial-only filter and a spatio-temporal filter.

16. The system as described in claim 13 , wherein said second filtering comprises a second filter.

17. The system as described in claim 16, wherein said second filter is a filter selected from the group consisting of a two-dimensional bilateral filter, a three-dimensional bilateral filter, a spatial filter and a spatio-temporal filter.

18. The system as described in claim 1 , wherein said filtering at said pixel location comprises selecting one of a plurality of filters based on said combination.

19. The system as described in claim 1 , wherein said filtering at said pixel location comprises selecting a set of filter parameters from a plurality of sets of filter parameters based on said combination.

20. A method for removing artifacts from a digital image, said method comprising:

a) receiving, in a computing system, a digital image;

b) determining an edge-strength indicator associated with a pixel location in said digital image;

c) determining a motion indicator associated with said pixel location in said digital image;

d) combining said edge-strength indicator and said motion indicator; and

e) filtering said digital image at said pixel location based on said combination.

21. The method as described in claim 20, wherein said determining an edge-strength indicator comprises:

a) for each pixel location in a region proximate to said pixel location, determining an edge-strength value associated with said each pixel location; and

b) averaging said edge-strength values.

22. The method as described in claim 20, wherein said filtering comprises a filter selected from the group consisting of a two-dimensional bilateral filter, a three-dimensional bilateral filter, a spatial-only filter and a spatio-temporal filter.

23. The method as described in claim 20 , wherein said edge-strength indicator is determined using a region based on a transform size associated with a compression method associated with said digital image.

24. The method as described in claim .20, wherein said filtering said digital image at said pixel location comprises selecting one of a plurality of filters based on said combination.

25. The method as described in claim 20, wherein said filtering said digital image at said pixel location comprises selecting a set of filter parameters from a plurality of sets of filter parameters based on said combination.

26. The method as described in claim 20, wherein said determining a motion indicator comprises measuring, between said digital image and a temporally neighboring image, a spatial displacement associated with said pixel location.

27. The method as described in claim 20, wherein said determining a motion indicator comprises detecting, between said digital image and a temporally neighboring image, a likelihood of motion associated with said pixel location.