Posted by
Kyle Michael Douglass on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Readout-noise-in-sCMOS-cameras-tp7588012p7588017.html
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Hi Sripad,
On 03/05/2018 06:54 PM, S Ram wrote:
>
> You made a comment that the distribution of noise in sCMOS is not Gaussian.
>
> Can you clarify whether you meant noise during the readout process (charge
> to voltage conversion step)? If it is not Gaussian, what is the underlying
> noise process? Is there any literature that you can point me to?
I would just like to highlight that a common source of confusion on this topic is the failure to distinguish between temporal noise and spatial non-uniformities.
The temporal noise refers to the noise in the ADU count value from a single pixel over time. Spatial non-uniformities, however, come in two flavors: a variation in the statistical moments of the temporal noise between pixels (dark signal non-uniformity, which includes read noise) and a variation in gain between pixels (photoresponse non-uniformity). As already mentioned, CMOS sensors suffer from both photoresponse and dark signal non-uniformities, and these are usually what are referred to when I see people talk about "CMOS noise."
Making the distinction between the two types of noise is important because I would think that a Gaussian is a pretty good model for *temporal* CMOS read noise for a *single* pixel. I would justify this statement by noting that typical measurements of the read noise produce the mean and variance of the pixel's dark signal ADU values. Unless higher order moments of the temporal noise are incorporated into the modeling, then it's difficult to justify a more complex distribution than a Gaussian.
I highly recommend the EMVA 1288 standard for more reading on these topics:
http://www.emva.org/standards-technology/emva-1288/emva-standard-1288-downloads/Best,
Kyle
--
Kyle M. Douglass, PhD
Post-doctoral researcher
The Laboratory of Experimental Biophysics
EPFL, Lausanne, Switzerland
http://kmdouglass.github.iohttp://leb.epfl.ch