The noise of a camera is generated by a large number of factors. Noise is created by the thermal agitation of electrons in electric conductors. It becomes apparent in the resulting camera image in the form of a random grey pattern varying from image to image. In practice, the shades of grey vary by several per cent despite a homogeneous illumination on a homogeneous surface. Sensor noise, digitalisation noise and the noise of all electronic components add up to an overall error which impairs the video image.