Image sensor with near-infrared and visible light pixels

1. An image sensor comprising:

an array of imaging pixels comprising visible light pixels and near-infrared light pixels; and

an array of color filter elements that covers the array of imaging pixels, wherein the imaging pixels are arranged in a pattern, wherein the pattern comprises a repeating 2×2 unit cell of pixel groups, and wherein each pixel group comprises a visible light pixel sub-group and a near-infrared light pixel sub-group.

2. The image sensor defined in claim 1 , wherein the visible light pixel sub-group of each pixel group comprises first and second adjacent visible light pixels.

3. The image sensor defined in claim 2 , wherein the near-infrared light pixel sub-group of each pixel group comprises first and second adjacent near-infrared light pixels.

4. The image sensor defined in claim 3 , wherein the 2×2 unit cell of pixel groups comprises first, second, third, and fourth pixel groups, wherein the visible light pixel sub-group of the first pixel group comprises a green pixel sub-group, wherein the visible light pixel sub-group of the second pixel group comprises a red pixel sub-group, wherein the visible light pixel sub-group of the third pixel group comprises a blue pixel sub-group, and wherein the visible light pixel sub-group of the fourth pixel group comprises a green pixel sub-group.

5. The image sensor defined in claim 4 , wherein the near-infrared light pixel sub-group of the first pixel group is interposed between the green pixel sub-group of the first group and the red pixel sub-group of the second pixel group and wherein the near-infrared light pixel sub-group of the third pixel group is interposed between the blue pixel sub-group of the third pixel group and the green pixel sub-group of the fourth pixel group.

6. The image sensor defined in claim 5 , wherein the red pixel sub-group of the second pixel group is interposed between the near-infrared light pixel sub-group of the first pixel group and the near-infrared light pixel sub-group of the second pixel group and wherein the green pixel sub-group of the fourth pixel group is interposed between the near-infrared light pixel sub-group of the third pixel group and the near-infrared light pixel sub-group of the fourth pixel group.

7. The image sensor defined in claim 5 , wherein the near-infrared light pixel sub-group of the second pixel group is interposed between the near-infrared light pixel sub-group of the first pixel group and the red pixel sub-group of the second pixel group and wherein the near-infrared light pixel sub-group of the fourth pixel group is interposed between the near-infrared light pixel sub-group of the third pixel group and the green pixel sub-group of the fourth pixel group.

8. The image sensor defined in claim 4 , wherein the green pixel sub-group of the first pixel group is interposed between the near-infrared light pixel sub-group of the first group and the near infrared-light pixel sub-group of the second pixel group and wherein the near-infrared light pixel sub-group of the third pixel group is interposed between the blue pixel sub-group of the third pixel group and the green pixel sub-group of the fourth pixel group.

9. The image sensor defined in claim 1 , further comprising:

a plurality of microlenses, wherein each visible light pixel sub-group is covered by a single respective microlens of the plurality of microlenses and wherein each near-infrared light pixel sub-group is covered by a single respective microlens of the plurality of microlenses.

10. The image sensor defined in claim 1 , wherein the imaging pixels of at least one pixel group are covered by a single microlens.

11. The image sensor defined in claim 1 , further comprising processing circuitry that is configured to:

for each pixel group of the repeating 2×2 unit cell of pixel groups, process signals from the visible light pixel sub-group and signals from the near-infrared light pixel sub-group to obtain a first processed set of image data and a second processed set of image data.

12. The image sensor defined in claim 11 , wherein the first processed set of image data is a set of monochrome image data and the second processed set of image data is a set of Bayer image data, and wherein the processing circuitry is configured to:

mix the set of monochrome image data with the set of Bayer image data into a set of output data that includes both near-infrared light information and visible light information; and

output the set of output data to a processor for demosaicing.

13. An image sensor comprising:

a plurality of photodiodes; and

a plurality of color filter elements arranged in a pattern, wherein each photodiode of the plurality of photodiodes is covered by a respective color filter element of the plurality of color filter elements, wherein the pattern comprises a repeating 2×2 unit cell of groups, and wherein each group comprises a first sub-group of visible light color filter elements and a second sub-group of near-infrared light color filter elements.

14. The image sensor defined in claim 13 , wherein the first sub-group of each group comprises first and second adjacent visible light color filter elements.

15. The image sensor defined in claim 14 , wherein the second sub-group of each group comprises first and second adjacent near-infrared light color filter elements.

16. The image sensor defined in claim 15 , wherein the 2×2 unit cell of groups comprises first and second groups above third and fourth groups, wherein the first sub-group of the first pixel group comprises first and second adjacent green color filter elements, wherein the first sub-group of the second group comprises first and second adjacent red color filter elements, wherein the first sub-group of the third group comprises first and second adjacent blue color filter elements, and wherein the first sub-group of the fourth group comprises first and second adjacent green color filter elements.

17. A method of processing signals from an array of imaging pixels that includes visible light pixels and near-infrared light pixels, the method comprising:

receiving signals from a 4×4 unit cell of imaging pixels that includes first, second, third and fourth groups of imaging pixels;

for each group of imaging pixels, processing the received signals to obtain a single representative value for the group of imaging pixels, wherein each group of imaging pixels includes both visible light pixels and near-infrared light pixels; and

outputting the representative value for each group of imaging pixels in a Bayer pattern.

18. The method defined in claim 17 , wherein processing the received signals for the first group of imaging pixels comprises determining the average of the signals from the visible light pixels and the near-infrared light pixels of the first group.

19. The method defined in claim 17 , wherein processing the received signals for the first group of imaging pixels comprises determining the average of the signals from the near-infrared light pixels of the first group.

20. The method defined in claim 17 , wherein processing the received signals for the first group of imaging pixels comprises determining a first average of the signals from the near-infrared light pixels of the first group, determining a second average of the signals from the visible light pixels of the first group, and subtracting the first average from the second average.

21. The method defined in claim 17 , wherein processing the received signals for the first group of imaging pixels comprises determining the average of the signals from the visible light pixels of the first group.

22. The image sensor defined in claim 1 , wherein the visible light pixel sub-group of each pixel group comprises at least first and second visible light pixels and wherein the near-infrared light pixel sub-group of each pixel group comprises at least first and second near-infrared light pixels.