Shizuoka University, Japan published a PhD Thesis "A Study on Noise Reduction in CMOS Image Sensors using High-Gain Front-end Readout Circuits" by Mohd Amrallah bin Mustafa, dated by Aug. 2013. The thesis goes through a quick overview of the major noise sources, including RTN:
Then, thesis goes through the ways to reduce the noise, like correlated multiple sampling (CMS), high gain ADC combined with PGA, and Histogram-based RTN Suppression and Averaging (HRS):
Then, a pixel with two amplifiers is proposed, where a selection circuit chooses the least noisy amplifier out of the two:
Then, thesis goes through the ways to reduce the noise, like correlated multiple sampling (CMS), high gain ADC combined with PGA, and Histogram-based RTN Suppression and Averaging (HRS):
Then, a pixel with two amplifiers is proposed, where a selection circuit chooses the least noisy amplifier out of the two: