Readout noise

Noise induced by the readout electronics, typically dominated by the noise on the floating diffusion amplifier and/or the analog-to-digital converter. It typically increases with clocking speed or frame readout speed. This noise is the result of the statistical variation or “error” that occurs when the amplifier attempts to reset itself to zero before the next image.

Rolling shutter readout

Operation of CMOS sensors referring to the line-by-line exposure and readout of the CMOS pixel array versus the all-at-once exposure followed by readout of CCD sensors, often called “snap shot” mode. In CMOS rolling shutter operation, there is a small temporal delay between the beginning of photon acquisition for the nth line of pixels versus the n+1th line, and so on. This delay is most likely to be an issue when the exposure time is less than the readout time and the imaged object is moving or changing rapidly.

Please refer to this link, if you would like to investigate readout modes further. 


To make SNR data even more approachable, a useful variation is to look at relative SNR (rSNR), where all data is normalized to an imaginary “perfect camera” that has 100 % QE and zero noise.