Tasseled cap
Under tasseled cap transform a method is meant to transform the spectral information of satellite data in spectral indicators. This index is particularly used in the analysis of vegetation (phenological stages).
background
In 1976 the Tasseled Cap Index was published by RJ Kauth and GS Thomas. It was generated on the basis of spectral information from the Landsat satellite. The Tasseled Cap coefficients, which are used in the linear equation of the Tasseled Cap Transformation, are sensor-specific and were therefore derived specifically for each sensor system. The index is related to principal component analysis and vegetation indices .
calculation
Six of seven Landsat TM bands are used for the algorithm, with three levels of information being generated:
- Tasseled Cap Band 1 ( brightness , a measured value for the floor)
- Tasseled Cap Band 2 ( greeness , a measured value for the vegetation)
- Tasseled Cap Band 3 ( wetness , a measured value for the interactions of soil and canopy moisture )
The algorithm for these three levels of information is a weighted sum of the Landsat bands (excluding thermal channel 6), where each band is multiplied by the specific coefficient (the weights):
- Brightness = 0.3037 (band 1) + 0.2793 (band 2) + 0.4743 (band 3) + 0.5585 (band 4) + 0.5082 (band 5) + 0.1863 (band 7)
- Greenness = - 0.2848 (volume 1) - 0.2435 (volume 2) - 0.5436 (volume 3) + 0.7243 (volume 4) + 0.0840 (volume 5) - 0.1800 (volume 7)
- Wetness = 0.1509 (band 1) + 0.1973 (band 2) + 0.3279 (band 3) + 0.3406 (band 4) - 0.7112 (band 5) - 0.4572 (band 7)
credentials
Kauth RJ and GS Thomas (1976): The tasseled Cap - A Graphic Description of the Spectral-Temporal Development of Agricultural Crops as Seen by LANDSAT . Proceedings of the Symposium on Machine Processing of Remotely Sensed Data