Hyperspectral image coding with LVQ-SPECK

Abstract

Enhanced versions of the LVQ-SPECK algorithm are presented that further exemplify the codec's good performance when dealing with multidimensional data sets. The two different alternatives might, in fact, be considered stepwise improvements over the original codec. First, an extended-range option is implemented, so that the number of spectral bands being simultaneously encoded is now a multiple of (instead of equal to) the codeword dimension. That in itself provides the means for much better rate allocation among the different bands. Then, use of the discrete wavelet transform over the spectral dimension, generating a wavelet packet decomposition of the original dataset is considered, and a substantial increase in coding performance is obtained, provided by the energy compaction characteristics of the transform. We provide results for the two different options of four-dimensional codebooks investigated, namely the shell-1 and shell-2 of the D 4 lattice, further cementing the idea that the latter is much more adept for use in this setting than the former. Finally we present comparison with other state-of-the-art codecs employed to the same task and show how competitive our proposed extensions are.