Method and apparatus for processing sensor images

• US 20030169353A1
• Filed: 03/11/2002
• Published: 09/11/2003
• Est. Priority Date: 03/11/2002
• Status: Abandoned Application

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Barash, Danny, Hel-Or, Yacov, Shaked, Doron, Keshet, Renato, Maurer, Ron P.
• Application Number:
  US10/096,025
• Publication Number:
  US 20030169353A1
• Time in Patent Office: Days
• US Class Current: 348/272
• CPC Class Codes: G06T 3/4015 Image demosaicing, e.g. colour filter arrays [CFA] or Bayer patterns
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values

Abstract

A sensor image is processed by applying a first demosaicing kernel to produce a sharp image; applying a second demosaicing kernel to produce a smooth image; and using the sharp and smooth images to produce an output image.

Claims

1. A method of processing a sensor image, the method comprising:

applying a first demosaicing kernel to the sensor image to produce a sharp image;

applying a second demosaicing kernel to the sensor image to produce a smooth image; and

using the sharp and smooth images to produce an output image.

2. The method of claim 1, wherein the first and second kernels use the same demosaicing algorithm to produce the sharp and smooth sensor images.

3. The method of claim 2, wherein the first and second kernels are designed with different optical blurs to produce the sharp and smooth images.

4. The method of claim 1, wherein the demosaicing kernels use linear-space invariant algorithms.

5. The method of claim 1, wherein the first kernel is a GIDE kernel.

6. The method of claim 1, wherein the second kernel is a GIDE kernel that does not correct for optical blur.

7. The method of claim 1, wherein using the sharp and smooth images includes determining differences between pixels of the sharp and smooth images;

and

selectively modifying the differences.

8. The method of claim 7, wherein the selectively modified differences are added to one of the sharp and smooth images.

9. The method of claim 7, wherein large differences indicating artifacts are substantially reduced in magnitude, mid-range differences indicating edges are increased in magnitude or left unchanged, and small differences indicating noise are reduced.

10. The method of claim 7, wherein differences are taken for each color plane, and at least one lookup table is used for different color planes.

11. The method of claim 7, wherein the differences are taken for the color planes, a single correction coefficient is derived from the differences, and the single correction coefficient is used to modify the differences for each of the different color planes.

12. The method of claim 7, wherein an edge-stop function is used to modify the differences.

13. The method of claim 1, wherein the sensor image is obtained by using a sensor including CFA cells having Bayer patterns;

and wherein each kernel uses a matrix for each location for each color plane.

14. Apparatus comprising a processor for performing demosaicing operations on a sensor image, the processor generating sharp and smooth images from the sensor image, and using the sharp and smooth images to generate an output image.

15. The apparatus of claim 14, wherein the processor uses the same demosaicing algorithm to produce the sharp and smooth sensor images.

16. The apparatus of claim 15, wherein the processor uses first and second kernels designed with different optical blurs to produce the sharp and smooth images.

17. The apparatus of claim 14, wherein processor uses a linear-space invariant algorithm to produce the sharp image.

18. The apparatus of claim 14, wherein the processor uses a GIDE kernel to produce the sharp image.

19. The apparatus of claim 14, wherein the processor uses a GIDE kernel to produce the smooth image, the GIDE kernel not correcting for optical blur.

20. The apparatus of claim 14, wherein the processor determines the differences between pixels of the sharp and smooth images;

and selectively modifies the differences to generate the output image.

21. The apparatus of claim 20, wherein the selectively modified differences are added to one of the sharp and smooth images.

22. The apparatus of claim 20, wherein large differences indicating artifacts are substantially reduced in magnitude, mid-range differences indicating edges are increased in magnitude or left unchanged, and small differences indicating noise are reduced.

23. The apparatus of claim 20, wherein the processor takes differences for each color plane, and uses at least one lookup table to selectively modify the differences for different color planes.

24. The apparatus of claim 20, wherein the processor takes differences for the color planes, derives a single correction coefficient from the differences, and uses the single correction coefficient to selectively modify the differences for each of the different color planes.

25. The apparatus of claim 14, wherein the processor uses an edge-stop function to modify the differences.

26. The apparatus of claim 14, further comprising a sensor array for producing the sensor image, the sensor including CFA cells having Bayer patterns;

wherein the demosaicing operations involve using a matrix for each location for each color plane.

27. A digital camera comprising:

a sensor array; and

a processor for performing first and second demosaicing operations on an output of the sensor array, the first demosaicing operation producing a sharp image, the second demosaicing operation producing a smooth image;

the processor using the sharp and smooth images to generate an output image.

28. An article for a processor, the article comprising memory encoded with a program for instructing the processor to perform first and second demosaicing operations on a sensor image, the first demosaicing operation producing a sharp image, the second demosaicing operation producing a smooth image;

the program further instructing the processor to use the sharp and smooth images to generate an output image.