Image sensor and dithering compensation for quantization error of image sensor

Abstract

An image sensor provides jitter compensation. A processed sensing signal generated by a sensing pixel array is used for jitter compensation in this case, employing a pseudo-random pattern. The pixel numbering pattern used for jitter compensation is not fixed, but rather the pixels are randomly numbered with a balanced probability. Based on a criterion corresponding to an average quantization error, jitter compensation is applied to pixels with numbers lower than that criterion, compensating them by a single unit.

Claims

1. An image sensor, comprising: An array of sensing pixels senses an image to generate a sensing signal; A signal processing circuit, coupled to the sensing pixel array, receives and processes the sensing signal; And an output circuit coupled to the signal processing circuit, for errors caused by quantization of signals smaller than one digital unit, performs pseudo-random pattern jitter compensation on the processed sensing signal, so that the pixel numbering pattern used for jitter compensation is not fixed, but randomly numbers the pixels with balanced probability. The output circuit compensates for pixels with numbers lower than the evaluation standard based on an average quantization error.

2. The image sensor as described in claim 1, wherein, The output circuit includes: a pseudo-random number generator that generates pseudo-random numbers to number pixels.

3. The image sensor as described in claim 2, wherein, The pseudo-random number generator includes: a first linear feedback shift register that generates values ​​based on a clock signal to achieve pseudo-random numbering of pixels.

4. The image sensor as described in claim 3, wherein, The pseudo-random number generator further includes: a finite field transformation module, which transforms the value generated by the first linear feedback shift register to a smaller finite range to generate pseudo-random numbers within that finite range for pixel numbering.

5. The image sensor as described in claim 3, wherein, The pseudo-random number generator changes the scrambling seed of the first linear feedback shift register according to a line synchronization signal.

6. The image sensor as described in claim 5, wherein, The pseudo-random number generator includes: a second linear feedback shift register that generates a scrambling seed based on the row synchronization signal and scrambles the first linear feedback shift register.

7. The image sensor as described in claim 6, wherein, The pseudo-random number generator changes the scrambling seed of the second linear feedback shift register according to a screen synchronization signal.

8. The image sensor as described in claim 7, wherein, The pseudo-random number generator further includes: a third linear feedback shift register that generates a scrambling seed based on the screen synchronization signal and scrambles the second linear feedback shift register.

9. The image sensor as described in claim 1, wherein: The sensing pixel array includes an optical black pixel array and a color active pixel array; and the output circuit realizes jitter compensation of pseudo-random patterns based on the quantization error of the black level correction of the optical black pixel array.

10. The image sensor as described in claim 9, wherein: The active pixel array adopts a Bayer arrangement to generate a blue signal, a red signal, a first green signal, and a second green signal, wherein the first green signal is sensed adjacent to the blue signal, and the second green signal is sensed adjacent to the red signal; and the output circuit separately implements jitter compensation for the pseudo-random patterns of the red signal, the blue signal, the first green signal, and the second green signal.

11. A method for image sensor jitter compensation, comprising: Receive a sensing signal processed by a sensing pixel array; For signals smaller than one digital unit, which are affected by quantization errors, the processed sensing signal is further subjected to jitter compensation using a pseudo-random pattern. This means that the pixel numbering pattern used for jitter compensation is not fixed, but rather the pixels are randomly numbered with a balanced probability. Furthermore, for pixels with numbers lower than the average quantization error, the digital unit compensation is applied based on a rating standard corresponding to that rating standard.

12. The image sensor jitter compensation method as described in claim 11, comprising: Operate a pseudo-random number generator to generate pseudo-random numbers to number pixels.

13. The image sensor jitter compensation method as described in claim 12 further includes: A first linear feedback shift register is operated according to a clock signal to generate a value to achieve pseudo-random numbering of pixels.

14. The image sensor jitter compensation method as described in claim 13 further includes: The value generated by the first linear feedback shift register is converted to a smaller finite range to generate pseudo-random numbers within that finite range for pixel numbering.

15. The image sensor jitter compensation method as described in claim 13 further includes: The scrambling seed of the first linear feedback shift register is changed according to the line synchronization signal.

16. The image sensor jitter compensation method as described in claim 15 is to operate a second linear feedback shift register according to the line synchronization signal to generate a line scrambling seed and scramble the first linear feedback shift register.

17. The image sensor jitter compensation method as described in claim 16 further includes: The scrambling seed of the second linear feedback shift register is changed according to the change of the synchronization signal of a screen.

18. The image sensor jitter compensation method as described in claim 17 is to operate a third linear feedback shift register according to the image synchronization signal to generate an image scrambling seed and scramble the second linear feedback shift register.

19. The image sensor jitter compensation method as described in claim 11, wherein: The sensing pixel array includes an optical black pixel array and a color active pixel array; jitter compensation of pseudo-random patterns is achieved based on the quantization error of the black level correction of the optical black pixel array.

20. The image sensor jitter compensation method as described in claim 19, wherein: The active pixel array adopts a Bayer arrangement to generate a blue signal, a red signal, a first green signal, and a second green signal. The first green signal is sensed adjacent to the blue signal, and the second green signal is sensed adjacent to the red signal. The jitter compensation of the pseudo-random patterns of the red signal, the blue signal, the first green signal, and the second green signal is implemented separately.

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