Major Types of Noise in Image Sensors
The most important aspect of the performance of image sensors is sensitivity as characterized by signal-to-noise ratio. The main temporal noise of a charged-couple device sensor is amplifier noise. An example is reset noise at floating diffusion, which belongs to circuitry noise. kTC noise is a phenomenon caused at the time of setting a capacitor to a certain voltage by switching it on and off to connect to a voltage source through devices having finite electrical resistance. Noise with a flat spectrum in a frequency space is also called white noise, meaning that it contains equal amounts of all frequency component. The physical basis of shot noise originates in the random arrival rate of a discrete particle such as a photon or an electron. Dark current shot noise, which is caused by the random generation of thermally excited electrons, also obeys the Poisson distribution.