Several artifacts are known to cause the effect described as Banding in Landsat Thematic Mapper (TM) data.
Figure 1. Example of Banding due to Scan Correlated Shift (SCS) in Landsat 5 TM Band 3 IC region data.
Click to view larger image. - .gif (149 KB)
Scan Correlated Shift (SCS) causes banding by forcing each scan to randomly choose one of the two or more bias states. This banding has a stable magnitude across each scan.
Figure 2. Example of Banding due to Memory Effect (ME) in Landsat 5 TM Band 3 data.
Click to view larger image. - .gif (166 KB)
Memory Effect (ME) causes banding-like patterns that change in magnitude across a scan. ME is caused by a large radiance transition in the scanning direction, from bright target to dark or from dark target to bright, either in the imagery or in the IC region of the data. For ME to create banding, the target is usually many scan lines in size, and if the target is in the imagery, the banding may visibly change over the bright target.
Calibration Error Banding, also known as "True Banding" or "Sweep Striping," is caused by errors in calibration algorithms that treat forward and reverse scans separately, so that one direction of scan has a different bias than the other. These errors create a Banding artifact that is stable across the scan and consistently alternates between high and low bias. True Banding is rare in TM data and is corrected when found, but it may be visible in data from older instruments.
|Scan Correlated Shift (SCS)||stable across a scan||randomly bright or dark|
|Memory Effect (ME)||changes across a scan||alternately bright and dark|
|Calibration Error Banding||stable across a scan||alternately bright and dark|
More than one of these artifacts can affect an instrument, causing banding of a complex character that may be difficult to diagnose with a cursory visual inspection. All forms of banding are known artifacts. They are all correctable and not cause for concern.