System with a random number generator used to remove contouring in CMOS imager data having an extended dynamic range

1. An apparatus, comprising:

a saturation detector detecting saturation of pixel data; and

a contour removal unit removing contour from the pixel data responsive to the detection, wherein th contour removal unit comprises a random number generator operable to produce a random number.

2. An apparatus as recited in claim 1 , wherein said saturation detector comprises a magnitude comparator receiving photodiode data of the pixel data and comparing the photodiode data to a threshold.

3. An apparatus as recited in claim 1 , wherein said contour removal unit comprises:

a selector coupled to said random number generator and selecting the bit range of the random number; and

an adder adding the random number to a sum of the photodiode data and the spillover rate adjusted diffusion data.

4. An apparatus as recited in claim 1 , wherein the pixel data comprises the floating rate of spillover diffusion data followed by the photodiode data in a serial data stream and said apparatus further comprises a serial data separator coupled to said saturation detector and said contour removal unit.

5. An apparatus as recited in claim 1 , wherein said saturation detector comprises a magnitude comparator receiving floating diffusion spillover data of the pixel data and comparing the floating diffusion spillover data to a threshold.

6. An apparatus for removing contouring from pixel data comprising a combination of photodiode data and spillover diffusion data with the spillover diffusion data followed by the photodiode data in a serial data stream, said apparatus comprising:

a serial data separator converting the serial data stream into parallel data;

a multiplier multiplying the spillover diffusion data by an integration ratio of the photodiode data and the spillover diffusion data and producing spillover rate adjusted diffusion data;

a saturation detector detecting saturation of the photodiode data of the pixel data, said saturation detector comprising a magnitude comparator receiving the photodiode data and comparing the photodiode data to a threshold; and

a contour removal unit removing contour from the pixel data responsive to the detection, said contour removal unit comprising:

a random number generator producing a random number;

a selector coupled to said generator and selecting a bit range of the random number; and

a three-port adder adding the random number, the photodiode data and the spillover rate adjusted diffusion data.

7. A method of image data processing, comprising:

determining whether the image data indicates photodiode saturation; and

removing contouring from the image data caused by the saturation, wherein said contouring removal comprises adding a random number to a sum of the photodiode data and spillover rate adjusted diffusion data.

8. A method as recited in claim 7 , wherein the determining determines whether photodiode data of the image data is greater than a threshold.

9. A method as recited in claim 7 , wherein:

said determining comprises comparing photodiode data of the image data of an image pixel with a non-spillover threshold; and

said removing comprises:

substituting a sum of a random number, photodiode data and spillover rate adjusted diffusion data for the image data.

10. A computer readable storage medium storing instructions for carrying out the steps of:

determining whether image data indicates photodiode saturation; and

removing contouring from the image data caused by the photodiode saturation, wherein said contouring removal comprises adding a random number to a sum of the photodiode data and spillover rate adjusted diffusion data.

11. A method as recited in claim 7 , wherein the determining determines whether floating diffusion spillover data of the image data is greater than a threshold.