Role of sensor in color rendering?

Started 3 months ago | Discussions thread
OP lélé Contributing Member • Posts: 595
Re: Sensor Cross-Talk

The Ghost of Caravaggio wrote:

lélé wrote:


I was wondering how the camera sensor, in particular the CFA design, could impact that.

Mays you have more info' ?

Cross-talk between pixels occurs when the signal for a given pixel is contaminated by signals from adjacent pixels. Inter-pixel cross talk is a form of correlated (time-independent) noise - i.e. artifacts. Besides color hue distortion, pixel electrical cross talk is one source of fixed-pattern noise.

The sensor photo-diode , the color filter and the micro-lens arrays' design and performance together impact cross-talk interference.

There are several sources of pixel cross talk.

Cross-talk can be a property of the sensor photo-diode array. Electrical cross-talk where the charge from one pixel leaks to adjacent pixels. This is called electron diffusion. Electrical cross-talk depends on the light incident angle and the position of the pixel. Electrical cross-talk can result in non-uniform color hue in a rendered image.

Cross talk also occurs due to optical contamination. The color-filter array R, G and B film layer materials are imperfect and can pass unwanted frequencies. Another optical source of cross-talk is the micro-lens array. The result is photo electrons for each photo-diode site generated by multiple colors - R = R + (B+G), B = B + (G+R) and G= G + (R+B).

Red light will contaminate green and blue pixels more than blue light contaminates red and green pixels due to inherent differences in silicon light absorption rates. This means the sensor IR filter layer properties also affect cross-talk.

Cross-talk artifacts are minimized by estimating cross-talk correction coefficients for each color channel. These corrections are applied in-camera to the raw data.

The quality of the CFA filter layer film, IR filter layer film and micro-lens array materials and manufacturing processes can impact cross-talk contamination.

Sensor cross-talk is discussed in detail here .

Thanks for sharing.

But do you think that, for example, the hue shift towards a 'slightly greenish brown' of caucasian skin tones when viewed from an angle and in the shadow is really caused by cross-talking?

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