The Tasseled Cap Transformation is a technique commonly used in land cover mapping or other classification projects. It takes the linear combination of satellite imagery bands and a specialized coefficient matrix to create a n-band image with the first 3 bands containing the majority of the useful information, similar to Principal Component Analysis. The first three bands created are generally held to represent Brightness, Greenness and Wetness. The coefficient matrix, which is unique to each imaging sensor, is based on image statistics and empirical observations. The matrix used in this model for the Landsat 8 OLI sensor is as follows (note that the first band of Landsat 8 OLI imagery, coastal aerosol, is effectively dropped):
|LS 8 Band 1||LS 8 Band 2||LS 8 Band 3||LS 8 Band 4||LS 8 Band 5||LS 8 Band 6||LS 8 Band 7|
Other Landsat sensors can be transformed to Tasseled Cap from the Raster tab / Resolution group / Spectral pulldown.
Assumptions: The Landsat 8 OLI imagery should have been previously corrected to at-satellite reflectance values. This greatly increases the accuracy of the tasseled-cap transform. Information on this procedure can be found here: http://landsat.usgs.gov/Landsat8_Using_Product.php
Below you can see how the resulting first 3 bands compare individually to the original image, which is displayed RGB to 4/3/2.
Muhammad Hasan Ali Baig, Lifu Zhang, Tong Shuai & Qingxi Tong (2014)
Derivation of a tasselled cap transformation based on Landsat 8 at-satellite reflectance,
Remote Sensing Letters, 5:5, 423-431, DOI: 10.1080/2150704X.2014.915434