Artifact reduction in a digital video

• US 7,620,241 B2
• Filed: 11/30/2004
• Issued: 11/17/2009
• Est. Priority Date: 11/30/2004
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Fan, Jian, Silverstein, D. Amnon, Lin, Qian
• Primary Examiner(s): Werner, Brian P
• Assistant Examiner(s): PATEL, JAYESH A
• Application Number:
  US10/999,739
• Publication Number:
  US 20060115178A1
• Time in Patent Office: 1,813 Days
• Field of Search: 382/201, 348/246
• US Class Current: 382/167
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/77 Retouching; Inpainting; Scratch removal
• CPC Class Codes: G06T 7/13 Edge detection
• CPC Class Codes: H04N 5/213 Circuitry for suppressing or minimising impulsive noise for suppressing or minimising disturbance in image signal generation H04N23/81
• CPC Class Codes: H04N 9/646 for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters

Abstract

A method performed by a processing system is provided. The method comprises detecting an artifact in a first frame of a digital video using a plurality of edges identified in the first frame and replacing a region that encompasses the artifact in the first frame with a corresponding region from a second frame.

Claims

1. A method performed by a processing system, the method comprising:

separately calculating first and second gradients for first and second color planes, respectively, of a first frame of a digital video with the processing system;

comparing the first gradient to the second gradient to identify a set of candidate pixels of an artifact in the first color plane of the first frame with the processing system;

comparing pixel values of the first color plane that correspond to the set of candidate pixels to corresponding pixel values of the second color plane to verify that the set of candidate pixels form the artifact in the first color plane of the first frame with the processing system; and

replacing a region that encompasses the artifact in the first color plane of the first frame with a corresponding region from the first color plane of a second frame with the processing system.

2. The method of claim 1 further comprising:

detecting a plurality of edges in the first color plane of the first frame using the first gradient, wherein the set of candidate pixels correspond to the plurality of edges with the processing system.

3. The method of claim 1 further comprising:

comparing a plurality of gradient magnitudes of the first gradient to a threshold to identify the set of candidate pixels with the processing system.

4. The method of claim 3 further comprising:

setting each one of the plurality of gradient magnitudes that is less than or equal to the threshold to zero with the processing system.

5. The method of claim 1 further comprising:

determining that an average color of pixels that comprise the artifact differs significantly from an average color of pixels that comprise the region that encompasses the artifact in the first color plane of the first frame outside of the artifact to verify that the set of candidate pixels form the artifact prior to replacing the region that encompasses the artifact in the first frame with the corresponding region from the second frame with the processing system.

6. The method of claim 1 wherein the second frame comprises a previous frame from the first frame.

7. The method of claim 1 wherein the second frame comprises a next frame from the first frame.

8. The method of claim 1 further comprising:

performing block matching between the first color plane of the second frame and the first color plane of the first frame with the processing system.

9. The method of claim 8 further comprising:

performing block matching between the first color plane of a third frame and the first color plane of the first frame with the processing system.

10. The method of claim 9 wherein second frame comprises a previous frame with respect to the first frame, and wherein the third frame comprises a next frame with respect to the first frame.

11. The method of claim 9 wherein second frame comprises a next frame with respect to the first frame, and wherein the third frame comprises a previous frame with respect to the first frame.

26. The method of claim 1 further comprising:

generating the first color plane of the first frame from a first color filmstrip with the processing system; and

generating the second color plane of the first frame from a second color filmstrip with the processing system.

12. A system comprising:

a processor; and

a memory system for storing a digital video and an artifact reduction module;

wherein the processor is configured to execute the artifact reduction module to;

separately calculate first and second gradients for first and second color planes, respectively, of a first frame of a digital video;

compare the first gradient to the second gradient to identify a set of candidate pixels of an artifact in the first color plane of the first frame;

compare pixel values of the first color plane that correspond to the set of candidate pixels to corresponding pixel values of the second color plane to verify that the set of candidate pixels form the artifact in the first color plane of the first frame; and

replace a region that encompasses the artifact in the first color plane of the first frame with a corresponding region from the first color plane of a second frame.

13. The system of claim 12 wherein the region and the corresponding region each comprise a rectangular region.

14. The system of claim 12 wherein the processor is configured to execute the artifact reduction module to:

detect a plurality of edges in the first color plane of the first frame using the first gradient, wherein the set of candidate pixels correspond to the plurality of edges.

15. The system of claim 14 wherein the processor is configured to execute the artifact reduction module to:

include a plurality of gradient magnitudes in the first gradient that is between at least two of the set of candidate pixels in the set of candidate pixels.

16. The system of claim 12 wherein the processor is configured to execute the artifact reduction module to:

compare a plurality of gradient magnitudes of the first gradient to a threshold to identify the set of candidate pixels.

17. The system of claim 16 wherein the processor is configured to execute the artifact reduction module to:

set each one of the plurality of gradient magnitudes that is less than or equal to the threshold to zero.

18. The system of claim 12 wherein the first frame comprises the first color plane, and wherein the processor is configured to execute the artifact reduction module to:

determine that an average color of pixels that comprise the artifact differs significantly from an average color of pixels that comprise the region that encompasses the artifact in the first color plane of the first frame outside of the artifact to verify that the set of candidate pixels form the artifact prior to replacing the region that encompasses the artifact in the first frame with the corresponding region from the second frame.

19. The system of claim 12 wherein the processor is configured to execute the artifact reduction module to:

perform block matching between the first color plane of the second frame and the first color plane of the first frame.

20. The system of claim 12 wherein the processor is configured to execute the artifact reduction module to:

perform block matching between the first color plane of a third frame and the first color plane of the first frame.

27. The system of claim 12 wherein the first color plane of the first frame is generated from a first color filmstrip, and wherein the second color plane of the first frame is generated from a second color filmstrip.

28. The system of claim 12 wherein the first color plane of the first frame is generated from a first color filmstrip, and wherein the second color plane of the first frame is generated from a second color filmstrip.

21. A system comprising:

means for separately calculating first and second gradients for first and second color planes, respectively, of a first frame of a digital video;

means for comparing the first gradient to the second gradient to identify a set of candidate pixels of an artifact in the first color plane of the first frame;

means for comparing pixel values of the first color plane that correspond to the set of candidate pixels to corresponding pixel values of the second color plane to verify that the set of candidate pixels form the artifact in the first color plane of the first frame; and

means for replacing a region that encompasses the artifact in first color plane of the the first frame with a corresponding region from the first color plane of a second frame.

22. A computer-readable medium encoded with computer-readable instructions for causing the computer to generate enhanced video comprising:

separately calculating first and second gradients for first and second color planes, respectively, of a first frame of a digital video;

comparing the first gradient to the second gradient to identify a set of candidate pixels of an artifact in the first color plane of the first frame;

comparing pixel values of the first color plane that correspond to the set of candidate pixels to corresponding pixel values of the second color plane to verify that the set of candidate pixels form the artifact in the first color plane of the first frame; and

replacing a region that encompasses the artifact in first color plane of the the first frame with a corresponding region from the first color plane of a second frame.

23. The computer-readable medium of claim 22 wherein the computer-readable medium includes instructions executable by the computer for:

detecting a plurality of edges in the first color plane of the first frame using the first gradient, wherein the set of candidate pixels correspond to the plurality of edges.

24. The computer-readable medium of claim 22 wherein the computer-readable medium includes instructions executable by the computer for:

determining that an average color of pixels that comprise the artifact differs significantly from an average color of pixels that comprise the region that encompasses the artifact in the first color plane of the first frame outside of the artifact to verify that the set of candidate pixels form the artifact prior to replacing the region that encompasses the artifact in the first frame with the corresponding region from the second frame.

25. The computer-readable medium of claim 22 wherein the computer-readable medium includes instructions executable by the computer for:

performing block matching between the first color plane of the second frame and the first color plane of the first frame; and

performing block matching between the first color plane of a third frame and the first color plane of the first frame.