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Assessment of inter-slice bit-allocation strategies in the application of JPEG2000 to ultraspectral sounder data

Presented here is a study comparing various inter-slice bit-allocation strategies when applying JPEG2000 part 2 to ultraspectral sounder satellite data. Two families of algorithms are compared: the first is strictly variance based for which traditional approaches and some variations are used; the second uses rate distortion curves (RDCs) to optimally allocate slice bit-rates in the MSE sense, analogous to the way the PCRD algorithm uses RDCs of code-blocks in the baseline JPEG2000 method. The rate distortion curves are either experimentally gathered or analytically modeled using techniques discussed in previous papers. An additional approach to gather RDCs is considered using the slope-length information computed by a JPEG2000 encoder. The study is done using six different granules of ultraspectral sounder data made available by NOAA. Every subset contains 1,501 spectral bands, each consisting of 90 by 135 pixels, which are decorrelated using either a Karhunen-Loeve transform (KLT) or the discrete wavelet transform (DWT). The most complex RDC-based optimal approach is used to establish a lower distortion bound, in addition to characterizing the typical distortion performance achievable when compressing spectrally decorrelated sounder data with JPEG2000. The bound is used as the basis of comparison against the other methods studied. Moreover, the software tool CompressMD developed by our group is used to provide all data handling, algorithm implementations and collection of results.