Image sensor apparatus and methods employing unit pixel groups with overlapping green spectral content

1. An apparatus comprising:

an array of color-selective sensors arranged as a plurality of repeating 2×2 unit pixel groups, each sensor of a unit pixel group selective for a color including a green component, the unit pixel group comprising respective sensors selective for respective first and second colors and two sensors selective for a third color, wherein the array comprises columns containing only sensors selective for the third color alternating with columns containing sensors selective for the first and second colors.

2. The apparatus of claim 1 , wherein signals from the sensors of the unit pixel groups define a first color signal space, and further comprising an image processor circuit configured to receive image sensor signals from the array of color-selective sensors and to process the image sensor signals to generate image signals in a second color signal space.

3. The apparatus of claim 2 , wherein the image processor circuit comprises:

an interpolator circuit configured to generate, for a pixel having a color filter of a first one of the first, second and third colors, interpolated color signals corresponding to respective second and third ones of the first, second and third colors from signals generated by adjacent sensors having color filters of the respective second and third ones of the first, second and third colors; and

a color corrector circuit configured to receive the interpolated color signals and to combine the interpolated color signals to produce RGB signals.

4. The apparatus of claim 3 , wherein the image processor circuit is further configured to generate a chrominance signal from the RGB signals and to generate a luminance signal from the interpolated color signals.

5. The apparatus of claim 3 , wherein the image processor circuit is configured to identify a false color error pixel from image signals received from the color-selective sensors and to responsively compensate an interpolated color signal for the identified false color error pixel.

6. The apparatus of claim 1 , wherein a first column of the unit pixel group comprises a yellow filtered sensor and a cyan filtered sensor and wherein a second column of the unit pixel group comprises two green filtered sensors.

7. The apparatus of claim 6 , further comprising an image processor circuit configured to generate respective sets of yellow, cyan and first and second green signals for respective pixels and to combine the yellow, cyan and two green signals of the respective sets of yellow, cyan and first and second green signals to produce respective sets of RGB signals for the respective pixels.

8. The apparatus of claim 7 , wherein the image processor circuit comprises a crosstalk corrector circuit configured to combine the yellow signal and the first green signal for a given pixel to generate a red signal of the RGB signal set for the given pixel, to combine the cyan signal and the second green signal for the given pixel to generate a blue signal of the RGB signal set for the given pixel, and to combine the first and second green signals for the given pixel to generate a green signal of the RGB signal set for the given pixel.

9. The apparatus of claim 7 , wherein the image processor circuit comprises an interpolator circuit configured to receive image sensor signals from the array of color-selective sensors and to generate respective sets of yellow, cyan and first and second green signals for respective pixels from the received image sensor signals.

10. The apparatus of claim 8 , wherein the image processor circuit is further configured to apply a color correction matrix to the red signal, blue signal and the green signal of the RGB signal set for the given pixel to generate a color-corrected set of red, green and blue signals for the given pixel.

11. The apparatus of claim 8 , wherein the crosstalk corrector circuit is configured to subtract the first green signal from the yellow signal for the given pixel to generate the red signal of the RGB signal set for the given pixel, to subtract the second green signal from the cyan signal for the given pixel to generate the blue signal of the RGB signal set for the given pixel and to average the first and second green signals for the given pixel to generate the green signal of the RGB signal set for the given pixel.

12. A method comprising:

generating image sensor signals from an array of color-selective sensors arranged as a plurality of repeating 2×2 unit pixel groups, each sensor of a unit pixel group selective for a color including a green component, the unit pixel group comprising respective sensors selective for respective first and second colors and two sensors selective for a third color, the image sensor signals defining a first color signal space, wherein the array comprises columns containing only sensors selective for the third color alternating with columns containing sensors selective for the first and second colors; and

processing the image sensor signals to generate image signals in a second color signal space.

13. The method of claim 12 , wherein processing the image sensor signals to generate image signals in a second color signal space comprises:

for a pixel having a color filter of a first one of the first, second and third colors, interpolating color signals corresponding to respective second and third ones of the first, second and third colors from signals generated by adjacent sensors having color filters of the respective second and third ones of the first, second and third colors; and

combining the interpolated color signals to produce RGB signals.

14. The method of claim 13 , further comprising:

generating a chrominance signal from the RGB signals; and

generating a luminance signal from the interpolated color signals.

15. The method of claim 13 , further comprising:

identifying a false color error pixel from image signals received from the color-selective sensors; and

responsively compensating an interpolated color signal for the identified false color error pixel.

16. The method of claim 12 , wherein a first column of the unit pixel group comprises a yellow filtered sensor and a cyan filtered sensor and wherein a second column of the unit pixel group comprises two green filtered sensors.

17. The method of claim 16 , further comprising an image processor circuit configured to generate respective sets of yellow, cyan and first and second green signals for respective pixels and to combine the yellow, cyan and two green signals of the respective sets of yellow, cyan and first and second green signals to produce respective sets of RGB signals for the respective pixels.

18. The method of claim 17 , further comprising:

combining the yellow signal and the first green signal for a given pixel to generate a red signal of the RGB signal set for the given pixel;

combining the cyan signal and the second green signal for the given pixel to generate a blue signal of the RGB signal set for the given pixel; and

combining the first and second green signals for the given pixel to generate a green signal of the RGB signal set for the given pixel.

19. The method of claim 18 :

wherein combining the yellow signal and the first green signal for the given pixel to generate a red signal of the RGB signal set for the given pixel comprises subtracting the first green signal from the yellow signal for the given pixel to generate the red signal of the RGB signal set for the given pixel;

wherein combining the cyan signal and the second green signal for the given pixel to generate a blue signal of the RGB signal set for the given pixel comprises subtracting the second green signal from the cyan signal for the given pixel to generate the blue signal of the RGB signal set for the given pixel; and

wherein combining the first and second green signals for the given pixel to generate the green signal of the RGB signal set for the given pixel comprises averaging the first and second green signals for the given pixel to generate the green signal of the RGB signal set for the given pixel.

20. The method of claim 18 , further comprising applying a color correction matrix to the red signal, blue signal and green signal of the RGB signal set for the given pixel to generate a color-corrected set of red, green and blue signals for the given pixel.

21. A crosstalk correction method comprising:

receiving a set of color signals for a pixel, the set of color signals including a yellow signal, a cyan signal, a first green signal and a second green signal;

combining the yellow signal and the first green signal to generate a red signal of an RGB signal set;

combining the cyan signal and the second green signal to generate a blue signal of the RGB signal set; and

combining the first and second green signals to generate the green signal of the RGB signal set.

22. The method of claim 21 :

wherein combining the yellow signal and the first green signal to generate a red signal of the RGB signal set comprises subtracting the first green signal from the yellow signal to generate the red signal of the RGB signal set;

wherein combining the cyan signal and the second green signal to generate a blue signal of the RGB signal set comprises subtracting the second green signal from the cyan signal to generate the blue signal of the RGB signal set; and

wherein combining the first and second green signals to generate the green signal of the RGB signal set comprises averaging the first and second green signals to generate the green signal of the RGB signal set.

23. A false color error correction method for correcting false color errors generated by color signal interpolation from sensor signals from an array of pixel sensors including sensors of a first color and a sensors of a second color interleaved in a row of the array, the method comprising:

for each pixel of the row, determining a difference between a sensor signal output of the sensor and a sensor signal output from a sensor of the same color nearest thereto in a first direction;

identifying a pair of adjacent pixels of the first and second colors responsive to the determined differences; and

compensating interpolated color signals for the identified pair of adjacent pixels.

24. The method of claim 23 , wherein compensating interpolated color signals for the identified pair of adjacent pixels comprises:

for the pixel of the first color, adding an average of color signal values for pixels of the second color on respective sides of the pixel of the first color to an interpolated color signal of the second color associated with the pixel of the first color; and

for the pixel of the second color, subtracting an average of color signal values for pixels of the first color on respective sides of the pixel of the second color to an interpolated color signal of the first color associated with the pixel of the second color.