A novel method of lossless compression for 2-D astronomical spectra images

A novel method of lossless compression for astronomical spectra images is proposed in this paper. Firstly, Integer Wavelet Transform is adopted to perform decorrelation of the data. Afterwards, Embedded Zero-tree Wavelet encoder is employed to describe the zero-tree structure of wavelet coefficients, and then the resulting stream put through Embedded Zero-tree Wavelet encoder can be transformed to character string including only five characters that is easily compressed by entropy coding. Finally, Arithmetic encoder is chosen as the entropy coder here. Groups of simulation data based on LAMOST and observation data from SDSS are used in the experiment to demonstrate the new method, and the experimental results are much better than those of GZIP and JPEG2000.