Hyperspectral Data Processing: Algorithm Design and Analysis

22.4 Coding Techniques for Determining DDA

Finding signature discriminatory probabilities only accomplishes half the task. The other half task is to design a technique to allocate DDA required for each of signatures, based on their signature discriminatory probabilities. Suppose that each spectral dimension (i.e., spectral component) or spectral band can be only used to accommodate one and only one signature, then a binary value “1” can be used to indicate whether a spectral dimension or spectral band is being used for signature accommodation, “1” for being used and “0” for remaining “unused”. Consequently, DDA can be addressed by bit allocation where the number of spectral dimensions, q and the number of spectral bands, required for each signature corresponds to the coding length used to encode a source alphabet in source coding. This implies that finding variable-length code words using bit allocation is equivalent to finding variable spectral dimensions of q and variable spectral bands of for using DDA. The following three well-established coding schemes are readily applied to determine ...