A systematic radiometric Noise observed on both TM instruments on the Landsat 4 and 5 satellites. Since this SCS noise had only a finite set a values and was constant within any given scan, it was possible to correct for SCS noise during Ground processing by measuring the value of the step-change in the background taken during shutter obscuration of the image at the end of each scan and inferring the SCS state for that Detector and band. Since all detectors within a band Switch states at the SAME time, the effect of SCS noise is to produce patterns of Banding where different numbers of adjacent scans can be in the same state. The Frequency of change of states became less and less with the time on orbit. See banding and noise. (Source: Dr. John Barker)