Rod and cone response sensor

• US 7,880,785 B2
• Filed: 07/21/2004
• Issued: 02/01/2011
• Est. Priority Date: 07/21/2004
• Status: Expired due to Fees

• Current Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Original Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Inventors: Gallagher, Paul K.
• Primary Examiner(s): Tran; Sinh
• Assistant Examiner(s): Berardesca; Paul
• Application Number:
  US10/895,129
• Publication Number:
  US 20060017829A1
• Time in Patent Office: 2,386 Days
• Field of Search: 348/276, 348/272, 348/273, 348/274, 348/279, 348/280, 348/297, 348/362
• 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 25/133 including elements passing panchromatic light, e.g. filters passing white light
• 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 pixel comprising a photosensor that produces photo-generated charges during an integration period,

wherein said plurality of pixels are organized into groups of pixels, each group of pixels including at least two color filtered pixels and at least one non-color filtered pixel, wherein each said group of pixels comprises four pixels arranged on two rows, and

wherein at least two of said color filtered pixels and said at least one non-color filtered pixel of each said group each have integration periods that start and end at different times, and said integration period of said at least one non-color filtered pixel occurs during at least a portion of said integration periods of said color filtered pixels.

2. The pixel array of claim 1, wherein said at least one non-color filtered pixel has a shorter charge integration period than the color filtered pixels.

3. The pixel array of claim 1, wherein said at least one non-color filtered pixel is not filtered for near-infrared wavelengths.

4. The pixel array of claim 1, wherein said at least one non-color filtered pixel is filtered for near-infrared wavelengths.

5. The pixel array of claim 1, wherein each group of pixels includes a red filtered pixel, a blue filtered pixel, a green filtered pixel, and a non-color filtered pixel.

6. The pixel array of claim 1, wherein each group of pixels includes a red filtered pixel and a blue filtered pixel.

7. The pixel array of claim 6, wherein each group of pixels further includes two non-color filtered pixels.

8. The pixel array of claim 1, wherein each group of pixels includes a cyan filtered pixel, a magenta filtered pixel, and a yellow filtered pixel.

9. The pixel array of claim 1, wherein each group of pixels shares one readout circuit.

10. The pixel array of claim 5, wherein said integration period of said non-color filtered pixel is a shortest integration period, said red filtered pixel has a second integration period that is longer than said shortest integration period, said green filtered pixel has a third integration period that is longer than said second integration period, and said blue filtered pixel has a longest integration period that is longer than said third integration period.

11. The pixel array of claim 7, wherein said red and blue filtered pixels have a first integration period, wherein said first integration period is longer than said integration period of said at least one non-color filtered pixel.

12. A pixel array comprising:

a plurality of pixels, each pixel comprising a photosensor that produces photo-generated charges during an integration period,

wherein a first subset of said plurality of pixels are red color filtered pixels having a first integration period, a second subset of said plurality of pixels are blue color filtered pixels having a second integration period, and a third subset of said plurality of pixels are non-color filtered pixels having a third integration period,

wherein said first, second, and third integration periods all start and end at different times, and said first and second integration periods at least partially overlap said third integration period, and

wherein said plurality of pixels are organized into groups of pixels with each group of pixels including at least one pixel from each of said first, second, and third subsets, and wherein each said group of pixels comprises four pixels arranged on two rows.

13. The pixel array of claim 12, wherein

said first integration period has a first duration and the second integration period has a second duration, the first and second durations being substantially equal, and

said third integration period has a third duration that differs from said first and second durations.

14. The pixel array of claim 13, wherein said first and second durations are longer than said third duration.

15. The pixel array of claim 12, wherein said first, second, and third integration periods have respective first, second, and third durations, wherein said first, second, and third durations are different.

16. The pixel array of claim 12, wherein said non-color filtered pixels are not filtered for non-visible near-infrared wavelengths.

17. The pixel array of claim 12, further comprising a fourth subset of said plurality of pixels that are green filtered pixels having a fourth integration period with a fourth duration, wherein said fourth integration period starts and ends at different times than said first, second, and third integration periods.

18. The pixel array of claim 17, wherein said third duration is shorter than said first, second, and fourth durations.

19. The pixel array of claim 12, wherein all pixels in each said group of pixels share a common readout circuit.

20. The pixel array of claim 18, wherein each group of said groups of pixels includes at least one pixel from each of said first, second, third, and fourth subsets and wherein all pixels in said group share a common readout circuit.

21. An imaging device comprising:

a pixel array including a plurality of pixels, each pixel having a photosensor that produces photo-generated charges during an integration period, wherein a first subset of said plurality of pixels are pixels having a first integration period of a first duration, a second subset of said plurality of pixels are pixels having a second integration period of a second duration, and a third subset of said plurality of filtered pixels are pixels having a third integration period of a third duration, and wherein the pixels of said first subset are non-color filtered and the pixels of said second and third subsets are each color filtered, said plurality of pixels being organized into groups of pixels with each group of pixels including at least one pixel from each of said first, second, and third subsets, and wherein each said group of pixels comprises four pixels arranged on two rows;

a timing and control unit for controlling said first, second, and third durations such that said first duration is shorter than said second and third durations and said first duration occurs during at least a portion of said second and third durations, wherein said first, second, and third integration periods all start and end at different times; and

an image processor that corrects effects that result from said different integration periods of said first, second, and third subsets using signals read out from said first subset.

22. The imaging device of claim 21, wherein said image processor corrects temporal displacement of colors that results from the different integration periods of said first, second, and third subsets.

23. The imaging device of claim 21, wherein said image processor corrects motion blur by interpolating color data based on signals from said first subset of pixels.

24. 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;

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

transferring charges from said first plurality of photosensors to readout circuitry after said first integration period;

transferring charges from said second plurality of photosensors to readout circuitry after said second integration period; and

transferring charges from said third plurality of photosensors to readout circuitry after said third integration period,

wherein photosensors of said third plurality of photosensors receive non-color filtered incident light,

wherein said third integration period occurs during at least a portion of said first and second integration periods and said first, second, and third integration periods start and end at different times, and

wherein said first, second, and third pluralities of photosensors are organized into groups of photosensors with each group of photosensors including at least one pixel from each of said first, second, and third pluralities, and wherein each said group of photosensors comprises four photosensors arranged on two rows.

25. The method of claim 24, wherein said first integration period begins before said second integration period.

26. The method of claim 24, wherein said first integration period ends before said second integration period.

27. The method of claim 24 further comprising:

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

transferring charges from said fourth plurality of photosensors to readout circuitry after said fourth integration period.

28. The method of claim 27, wherein said third integration period occurs during at least a portion of said first, second, and fourth integration periods.

29. The method of claim 28, wherein said first, second, third, and fourth integration periods start and end at different times.

30. The method of claim 24, wherein said third integration period has a shortest duration.

31. A method of operating an imaging device comprising:

generating charges from color filtered incident light of a first color with a first plurality of photosensors in a row of a pixel array during a first integration period;

transferring charges from said first plurality of photosensors to readout circuitry after said first integration period;

generating charges from non-color filtered incident light with a second plurality of photosensors in said row of said pixel array during a second integration period, said first and second integration periods starting and ending at different times;

transferring charges from said second plurality of photosensors to said readout circuitry after said second integration period;

generating charges from color filtered incident light of a second color with a third plurality of photosensors in another row of a pixel array during a third integration period;

transferring charges from said third plurality of photosensors to said readout circuitry after said third integration period;

controlling said first, second, and third integration periods such that said second integration period is shorter than said first and third integration periods and occurs during at least a portion of said first and third integration periods; and

correcting effects resulting from said different integration periods of said first, second, and third pluralities of photosensors using signals read out from said second plurality of photosensors.

32. The method of claim 31, further comprising interpolating color information by subtracting signals from said first plurality or said third plurality of photosensors out of signals from said second plurality of photosensors.

33. The method of claim 31, wherein said step of correcting signals includes correcting temporal displacement of colors resulting from the different integration periods using signals read out from said second plurality of photosensors.

34. The method of claim 31, further comprising correcting motion blur using signals read out from said second plurality of photosensors.