each pixel the appropriate color for it to capture there are many types of cfas each based on a different color model referring to fig2 one frequently used cfa is based on the rgb color model as shown the interpolated signal from the imaging device 39 s sensor is further processed nonlinearly inside the camera the imaging device 39 s pattern noise also referred to as pixel noise or pixel non uniformity is defined see g c hoist ccd arrays cameras and displays 2 nd edition jcd publishing amp spie press usa 1998 as the noise component that is not reduced by frame averaging two main components of pattern noise are fixed pattern noise and photo response non uniformity noise pattern noise may also comprise in part some artifacts of processing e g cfa interpolation artifacts since the pattern noise does not change from image to image and is relatively stable over the device 39 s life and a reasonable range of conditions e g temperature it can identify the imaging device there are also a number of random noise sources in digital images introduced by imaging devices such as shot noise dark current shot noise circuit noise etc hoist ccd arrays cameras and displays j r janesick scientific charge coupled devices spie press monograph vol pm83 spie u2014 the international society for optical engineering january.