Image enhancement employing partial template matching

• US 7,412,108 B2
• Filed: 07/11/2007
• Issued: 08/12/2008
• Est. Priority Date: 07/23/2003
• Status: Expired due to Term

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Technology, Ltd. (Marvell Technology Group Limited)
• Inventors: Keithley, Douglas Gene
• Primary Examiner(s): PATEL, KANJIBHAI B
• Application Number:
  US11/827,602
• Publication Number:
  US 20070253633A1
• Time in Patent Office: 398 Days
• Field of Search: 382/209, 382217-221, 382/254, 382/266, 382/270, 382/274, 382298-300, 382/305, 358/1.1, 358/1.2, 358/3.27, 345/613
• US Class Current: 382/254
• CPC Class Codes: G06T 2207/10008 from scanner, fax or copier
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 5/00 Image enhancement or restoration
• CPC Class Codes: H04N 1/4092 Edge or detail enhancement

Abstract

A method of image-resolution enhancement employing partial-template matching, including storing at least a portion of an image, and selecting from the image a window comprising a plurality of adjacent line segments having pixels, the window including a target pixel. The method also includes comparing the pixels of the window with a template for a partial match, and responsive to a partial match being found, substituting an enhancement pixel for the target pixel. By allowing a partial match for enhancement instead of requiring a 100-percent match of the prior art, the method provides image-resolution enhancement for digital-image data having noise or other errors.

Claims

1. An image enhancement system, the system comprising:

memory adapted to store pixels corresponding to an image;

a selector adapted to select a plurality of stored pixels defining a window, where the window includes a target pixel;

a plurality of templates each having one or more pixels;

a pixel comparator adapted to compare pixels of interest in the window with corresponding pixels of a template of the plurality of templates; and

a pixel substitutor adapted to substitute an enhancement pixel for the target pixel in response to an occurrence of a partial match as determined by the pixel comparator, where a partial match occurs when a number of pixels of interest in the window pass their respective comparison and such number of pixels exceeds or equals a predetermined threshold.

2. The image enhancement system of claim 1 where the predetermined threshold is less than the total number of pixels of interest in the window.

3. The image enhancement system of claim 1, where the pixels of interest in the window are defined by a mask of an applied template of the plurality of templates.

4. The image enhancement system of claim 3, where the plurality of templates are prioritized.

5. The image enhancement system of claim 4, where the pixel substitutor substitutes an enhancement pixel from a highest priority partial matching template when the pixel comparator determines that there is a partial match between the pixels of interest in the window and more than one of the plurality of templates.

6. The image enhancement system of claim 5, where the pixel comparator sequentially compares the window with the plurality of templates based on the priority of each template.

7. The image enhancement system of claim 1, where the memory is adapted to store consecutive lines of pixels corresponding to the image.

8. The image enhancement system of claim 7, where the pixels of interest in the window comprise one or more pixels from a line above the target pixel, one or more pixels from a same line as the target pixel, and one or more pixels from a line below the target pixel.

9. The image enhancement system of claim 1, where the pixel comparator is adapted to compare pixels of interest in the window with corresponding pixels of a plurality of templates.

10. The image enhancement system of claim 1, where the pixel comparator is at least partially implemented in hardware.

11. The image enhancement system of claim 1, where the pixel comparator is further adapted to compare each pixel of a pixel-bit subset of the window as defined by a mask of a template with each corresponding pixel of a prediction-bit subset as defined by a pattern of the template.

12. The image enhancement system of claim 11, where the pixel-bit subset includes all the pixels of the window.

13. The image enhancement system of claim 1, where the predetermined threshold is at least 90% of the total number of pixels of interest in the window.

14. The image enhancement system of claim 1, where the predetermined threshold is at least 80% of the total number of pixels of interest in the window.

15. The image enhancement system of claim 1, where each template includes an enhancement pixel that may be substituted for the target pixel when a partial match is found.

16. The image enhancement system of claim 1, further comprising a rendering device adapted to reproduce the image with the enhancement pixel.

17. The system of claim 16, where the rendering device is selected from the group of rendering devices consisting of a monitor, a projection unit, a laser printer, an ink-jet printer, a dot-matrix printer, a thermal printer, and a plotter.

18. An image enhancement system, the system comprising:

memory means for storing pixels corresponding to an image;

selector means for selecting a plurality of stored pixels defining a window, where the window includes a target pixel;

template means for defining pixel comparison values and pixel patterns;

pixel comparator means for comparing pixels of interest in the window with corresponding pixels of the template means; and

pixel substitutor means for substituting an enhancement pixel for the target pixel in response to an occurrence of a partial match as determined by the pixel comparator means, where a partial match occurs when a number of pixels of interest in the window pass their respective comparison and such number of pixels exceeds or equals a predetermined threshold.

19. The image enhancement system of claim 18 where the predetermined threshold is less than the total number of pixels of interest in the window.

20. The image enhancement system of claim 18, where the pixels of interest in the window are defined by a mask of an applied template of the template means.

21. The image enhancement system of claim 18, where the memory means is adapted to store consecutive lines of pixels corresponding to the image.

22. The image enhancement system of claim 21, where the pixels of interest in the window comprise one or more pixels from a line above the target pixel, one or more pixels from a same line as the target pixel, and one or more pixels from a line below the target pixel.

23. The image enhancement system of claim 18, where the pixel comparator means is adapted to compare pixels of interest in the window with corresponding pixels of a plurality of templates of the template means.

24. The image enhancement system of claim 23, where the plurality of templates are prioritized.

25. The image enhancement system of claim 24, where the pixel substitutor means substitutes an enhancement pixel from a highest priority partial matching template when the pixel comparator means determines that there is a partial match between the pixels of interest in the window and more than one of the plurality of templates of the template means.

26. The image enhancement system of claim 24, where the pixel comparator means sequentially compares pixels of interest in the window with the plurality of templates based on the priority of each template.

27. The image enhancement system of claim 18, where the pixel comparator means is at least partially implemented in hardware.

28. The image enhancement system of claim 18, where the pixel comparator means is further adapted to compare each pixel of a pixel-bit subset of the window as defined by a mask of a template of the template means with each corresponding pixel of a prediction-bit subset as defined by a pattern of the template of the template means.

29. The image enhancement system of claim 28, where the pixel-bit subset includes all the pixels of the window.

30. The image enhancement system of claim 18, where the predetermined threshold is at least 90% of the total number of pixels of interest in the window.

31. The image enhancement system of claim 18, where the predetermined threshold is at least 80% of the total number of pixels of interest in the window.

32. The image enhancement system of claim 18, where each template includes an enhancement pixel that may be substituted for the target pixel when a partial match is found.

33. The image enhancement system of claim 18, further comprising a rendering means for reproducing the image with the enhancement pixel.

34. The image enhancement system of claim 33, where the rendering means is selected from a group of rendering devices consisting of a monitor, a projection unit, a laser printer, an ink-jet printer, a dot-matrix printer, a thermal printer, and a plotter.

35. A method for enhancing an image comprising:

storing pixels corresponding to an image;

selecting a plurality of stored pixels to define a window, where the window includes a target pixel;

defining one or more templates comprising pixel comparison values and pixel patterns;

comparing pixels of interest in the window with corresponding pixels of the one or more templates; and

substituting an enhancement pixel for the target pixel in response to an occurrence of a partial match, where a partial match occurs when a number of pixels of interest in the window pass their respective comparison and such number of pixels exceeds or equals a predetermined threshold.

36. The method of claim 35 where the predetermined threshold is less than the total number of pixels of interest in the window.

37. The method of claim 35, where the pixels of interest in the window are defined by a mask of an applied template of the one or more templates.

38. The method of claim 35, where the storing comprises storing consecutive lines of pixels corresponding to the image.

39. The method of claim 38, where the pixels of interests in the window comprise one or more pixels from a line above the target pixel, one or more pixels from a same line as the target pixel, and one or more pixels from a line below the target pixel.

40. The method of claim 35, where the comparing comprises comparing pixels of interest in the window with corresponding pixels of a plurality of templates.

41. The method of claim 40, further comprising prioritizing the plurality of templates.

42. The method of claim 41, where the substituting comprises substituting an enhancement pixel from a highest priority partial matching template when there is a partial match between the pixels of interest in the window and more than one of the plurality of templates.

43. The method of claim 41, where the comparing comprises sequentially comparing pixels of interest in the window with the plurality of templates based on the priority of each template.

44. The method of claim 35, where the comparing is at least partially executed in hardware.

45. The method of claim 35, where the comparing comprises comparing each pixel of a pixel-bit subset of the window as defined by a mask of a template of the one or more templates with each corresponding pixel of a prediction-bit subset as defined by a pattern of the template of the one or more template.

46. The method of claim 45, where the pixel-bit subset includes all the pixels of the window.

47. The method of claim 35, where the predetermined threshold is at least 90% of the total number of pixels of interest in the window.

48. The method of claim 35, wherein the predetermined threshold is at least 80% of the total number of pixels of interest in the window.

49. The method of claim 35, where each template of the one or more templates includes an enhancement pixel that may be substituted for the target pixel when a partial match is found.

50. The method of claim 35, further comprising reproducing the image with the enhancement pixel.

51. The method of claim 50, where the reproducing is executed with a rendering device selected from a group of rendering devices consisting of a monitor, a projection unit, a laser printer, an inkjet printer, a dot-matrix printer, a thermal printer, and a plotter.