For a sensor carrying four bands, Gram–Schmidt orthogonalization is used (Huang et al.
2002; Crist and Cicone 1984b; Kauth and Thomas 1976). For higher number of bands,
after applying PCA, all three axes are rotated to separate different features from each
other. It has been found that there is no standard mechanism in literature currently
available for this post-PCA rotation, and thus rotation is subjected to interpretation
(Lobser and Cohen 2007). Lobser and Cohen (2007) attempted to standardize derivation
of transformation coefficients for future sensors. By following the standard developed by
them, the below-mentioned approaches were followed: