Methods and devices for increasing the spectral response of an image sensor

1. An imaging device, comprising:

a pixel array; and

a color filter array situated on the pixel array, wherein the color filter array comprises multiple groups of filters; and

wherein at least one group comprises:

a first color and a second color; wherein the second color is selected from the group consisting of transparent and white;

a majority of filters having the first color; and

at least one filter having the second color.

2. The imaging device of claim 1 , wherein the plurality of filters having the first color forms a shape having only four sides of equal length.

3. The imaging device of claim 1 , wherein the filter having the second color is located in a geometric center of the group.

4. The imaging device of claim 1 , wherein the the second color is transparent filter.

5. The imaging device of claim 1 , wherein the group comprises at least four filters.

6. The imaging device of claim 1 , wherein at least one group has a geometric area greater than that of a different group.

7. The imaging device of claim 1 , wherein at least one group forms an asymmetric shape.

8. A method for augmenting a spectral response of a pixel array based on lighting conditions, comprising:

capturing light with an imaging device comprising:

a plurality of pixels, wherein each pixel comprises a photosensitive element;

a plurality of multi-color filters situated on the pixel array, wherein the filters are arranged in groups; and

wherein at least one group comprises:

a majority of filters having a first color; and

at least one filter having a second color;

 wherein the second color is selected from the group consisting of transparent and white;

obtaining a signal for each pixel, wherein the signal is proportional to the amount of light on the photosensitive element; and

summing the signals for at least the pixels with same-color filters.

9. The method of claim 8 , further comprising selectively enabling the utilization of the pixel signal associated with the color filter having the second color based on a predetermined threshold value.

10. The method of claim 9 , further comprising combining the pixel signal associated with the filter having the second color with the pixel signals associated with the filters having the first color.

11. The method of claim 8 , wherein summing the signals comprises summing the signals in the group on a shared floating diffusion region.

12. The method of claim 8 , wherein summing the signals comprises summing the signals in the group in an analog domain.

13. The method of claim 8 , further comprising individually reading out the pixel signals, and wherein summing the signals comprises summing the signals in a digital domain.

14. The method of claim 8 , further comprising applying a color correction matrix to the summed pixel signals.

15. A system for producing higher-quality images at varying light levels, comprising:

a pixel array of color pixels, wherein each pixel comprises a color filter, wherein the color pixels are arranged in groups;

wherein at least one group comprises:

at least 9 color pixels from the array of color pixels;

at most, a first color and a second color;

a plurality of color pixels from the at least 9 color pixels having the first color; and

a single color pixel from the at least 9 color pixels having the second color, and wherein the filter having the second color is located in a geometric center of the group;

an image signal processor coupled to the pixel array, wherein the image signal processor applies a color correction matrix; and

an output device coupled to the image signal processor for displaying a corrected image.

16. The system of claim 15 , further comprising a shared floating diffusion region, wherein multiple pixels corresponding to at least one group of color filters are coupled to the shared floating diffusion region.

17. The system of claim 15 , wherein the second color is transparent.

18. The system of claim 15 , wherein the color correction matrix optimizes a signal to noise ratio of the corrected image.

19. The system of claim 15 , wherein the color correction matrix optimizes the color fidelity of the corrected image.