It appears on the same pixels at different times when images are taken. It can be suppressed with noise reduction and on-chip noise reduction technology. The main approach is CDS (Correlated Double Sampling), having one light signal read by two circuits. First, only the noise is read. Next, it is read in combination with the light signal. When the noise component is subtracted from the combined signal, the
fixed-pattern noise can be eliminated. Canonâs four-transistor technology is crucial in this process.