Rod and cone response sensor

• US 20060017829A1
• Filed: 07/21/2004
• Published: 01/26/2006
• Est. Priority Date: 07/21/2004
• Status: Active Grant

• Current Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Original Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Inventors: Gallagher, Paul K.
• Granted Patent: US 7,880,785 B2
• Time in Patent Office: Days
• US Class Current: 348/276
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/131 including elements passing infrared wavelengths
• CPC Class Codes: H04N 25/136 using complementary colours

Abstract

An imager having color sensitivity in any lighting condition is provided by replacing at least one of the green color filtered pixels in a Bayer pattern array with an non-color filtered pixel and providing a different integration period for each color channel. When replacing a color filtered pixel with a non-color filtered pixel, the benefits of both color sensitivity and light sensitivity may be harnessed by providing the color filtered pixels with a longer integration period than the non-color filtered pixels. Color information may be interpolated by performing subtraction logic using non-color and color filter information from adjacent pixels in back-end processing. Integration times for each color channel can be adapted to minimize filter transmission and sensor absorption differences within each frame of data. Temporal displacement of colors of moving objects by having different integration periods may be corrected in back-end processing. Back-end processing may also correct motion blur.

Claims

1. A pixel array comprising:

a plurality of pixels, each comprising a photosensor for producing photo-generated charges during an integration period, wherein a first group of said plurality of pixels are color filtered and a second group of said plurality of pixels are non-color filtered.

2. The pixel array of claim 1, wherein the pixels of said second group have a shorter charge integration period than pixels of said first group.

3. The pixel array of claim 1, wherein said non-color filtered pixels are also not filtered for infrared wavelengths.

4. The pixel array of claim 1, wherein said non-color filtered pixels are filtered for infrared wavelengths.

5. The pixel array of claim 1, wherein said plurality of pixels are grouped with each group having more than one pixel, at least one of the pixels being non-color filtered.

6. The pixel array of claim 5, wherein each group comprises one each of a red, blue, green, and non-color filter.

7. The pixel array of claim 5, wherein each group of pixels further comprises one pixel each having respective associated red, green, and blue color filters.

8. The pixel array of claim 5, wherein each group comprises a red, blue, and two non-color filtered pixels.

9. The pixel array of claim 5, wherein each group of four pixel cells comprises one each of a pixel cell having cyan, magenta, and yellow color filters.

10. The pixel array of claim 5, wherein each group of four pixel cells shares one readout circuit.

11. The pixel array of claim 1, wherein pixels of said first group have a different integration from the pixels of said second group.

12. The pixel array of claim 7, wherein said non-color filtered pixel has the shortest integration period, said red color filtered pixel has a longer integration period than said non-color filtered pixel, said green color filtered pixel has a longer integration period than said red color filtered pixels, and said blue color filtered pixel has the longest integration period of said group of four pixels.

13. The pixel array of claim 8, wherein said red and blue color filtered pixels have a first integration period and said two non-color filtered pixels have a second integration period, wherein said first integration period is longer than said second integration period.

14. The pixel array of claim 5, wherein said group of four pixels comprises two pixels on each of two rows.

15. A pixel array comprising a plurality of pixel cells comprising:

a photosensor for producing photo generated charges during a plurality of integration periods, wherein a first group of said plurality of pixels are red color filtered, a second group of said plurality of pixels are blue color filtered, and a third group of said plurality of pixels are non-color filtered.

16. The pixel array of claim 15, wherein said first group has a first integration period, said second group has a second integration period, and said third group has a third integration period.

17. The pixel array of claim 16, wherein said first and second integration periods have the same duration, which is different from said third integration period.

18. The pixel array of claim 17, wherein said first and second integration periods are longer than said third integration period.

19. The pixel array of claim 16, wherein said first, second, and third integration periods have different durations.

20. The pixel array of claim 15, wherein non-color filtered pixels are also not filtered for infrared wavelengths.

21. The pixel array of claim 15, wherein said plurality of pixels are grouped with each group having one red color filtered pixel, one blue color filtered pixel, and one non-color filtered pixel.

22. The pixel array of claim 19, further comprising a fourth group of group of pixels that are green color filtered having a fourth integration period with a different duration from said first, second, and third integration periods.

23. The pixel array of claim 22, wherein said third integration period has the shortest duration.

24. The pixel array of claim 21, wherein each group shares a common readout circuit.

25. The pixel array of claim 23, wherein pixels are grouped in four-pixel sets with each set having four pixels, one each of said first, second, third, and fourth group of pixels, each set sharing a common readout circuit.

26. An imaging device comprising:

a pixel array comprising a plurality of pixels, each comprising a photosensor for producing photo-generated charges during an integration period, wherein a first group of said plurality of pixels has a first integration period and a second group of said plurality of pixels has a second integration period;

a timing and control unit for controlling the integration periods of said pixels; and

an image processor for processing signals read out by said readout circuitry.

27. The imaging device of claim 26, wherein said first integration period is shorter than said second integration period.

28. The imaging device of claim 27, wherein said first group of said plurality of pixels are non-color filtered and said second group of said plurality of pixels are color filtered.

29. The imaging device of claim 28, further comprising at least a third group of said plurality of color filtered pixels having a third integration period.

30. The imaging device of claim 29, wherein said third group of pixels have a different color filter than said second group of pixels.

31. The imaging device of claim 27, wherein said image processor corrects temporal displacement of colors due to the different integration periods.

32. The imaging device of claim 27, wherein said image processor corrects motion blur by interpolating color data based on data from said first group of pixels having a shorter integration period.

33. A method of operating a pixel array comprising:

generating charges with a first plurality of photosensors during a first integration period;

generating charges with a second plurality of photosensors during a second integration period;

transferring charges from said first plurality of photosensors to readout circuitry at the end of said first integration period;

transferring charges from said second plurality of photosensors to readout circuitry at the end of said second integration period, wherein said first and second integration periods partially overlap.

34. The method of claim 33, wherein said first integration period begins before said second integration period.

35. The method of claim 33, wherein said first integration period ends at a different time than said second integration period.

36. The method of claim 35 further comprising:

generating charges with a third plurality of photosensors during a third integration period;

generating charges with a fourth plurality of photosensors during a fourth integration period;

transferring charges from said third plurality of photosensors to readout circuitry at the end of said third integration period; and

transferring charges from said fourth plurality of photosensors to readout circuitry at the end of said fourth integration period.

37. The method of claim 36, wherein said first, second, third, and fourth integration periods partially overlap.

38. The method of claim 37, wherein said first, second, third, and fourth integration periods end at different times.

39. The method of claim 33, wherein one of said plurality of photosensors does not have a color filter or near-infrared filter over it.

40. The method of claim 39, wherein said unfiltered photosensors are integrated during the shortest integration period.

41. A method of operating an imaging device comprising:

generating charges with a first plurality of photosensors in a pixel array during a first integration period;

transferring charges from said first plurality of photosensors to readout circuitry at the end of said first integration period;

generating charges with a second plurality of photosensors in a pixel array during a second integration period;

transferring charges from said second plurality of photosensors to readout circuitry at the end of said second integration period;

controlling the integration periods of said pixel array such that said integration periods end at different times; and

processing signals read out by said readout circuitry.

42. The method of claim 41, wherein said integration periods partially overlap.

43. The method of claim 41, wherein said first integration period is longer than said second integration period.

44. The method of claim 41, wherein said step of generating charges with said second plurality of photosensors comprises generating charges from non-color filtered incident light.

45. The method of claim 44, wherein said step of generating charges with said first plurality of photosensors comprises generating charges from color filtered incident light.

46. The method of claim 45, wherein said step of processing signals includes interpolating color information by subtracting signals from said first integration period out of signals from said second integration period.

47. The method of claim 45, wherein said step of processing signals corrects temporal displacement of colors due to the different integration periods.

48. The method of claim 45, wherein said step of processing signals corrects motion blur.