the random noise generated by the amplifier circuitry in the camera. Periodic
noise can result from stray periodic signals finding their way into the camera
circuits. Quantization noise results from conversion of the continuous bright-
ness values into integers. As a rule of thumb, the overall noise level will be the
root sum square of the various noise source amplitudes. One can control
quantization noise by using enough bits per pixel. Generally quantization
noise can be, and should be, kept below the other noise sources in amplitude.
Eight-bit digitizers are quite common, and this puts the quantization noise level
(1=256) below 0.5 percent of the total dynamic range. Some applications,
however, require the more expensive 10-bit or 12-bit digitizers. ...