| Hyper-spectral image is a three-dimensional image, has the high spatial resolution and alarge number of spectral channels. But the high spatial resolution is taken for the greater dataamount and bigger dimension. The huge data amount has brought certain difficulty for thestorage and the transmission, so compression to the image is necessary. Because the hyperspectralimage is a kind of important data, and it need fast speed and high reliability.Thereforelossless or near lossless compression method should be used as far as possible.In this paper,algorithms of hyper-spectral image compression are proposed.The Hyper-spectral image has much strong spatial correla tion and spectroscopycorrela tion. According to these, 3D-SPIHT encoding algorithm,which is based on the threedimensional wavelet transformation(3D-DW T),has been used in the paper.And 3D-DWT wasused to wipe off the redunda ncy of spatial and spectroscopy. Then a kind of 3 dimensionalSpatial Orientation Tree was constructed by the coefficients of wavelet transform.Finally,thecoefficients of wavelet transform were coded by 3D-SPIHT algorithm.Two kinds of wavelet,9/7 wavelet and 5/3 wavelet,were used in the paper.They are bothbase on the wavelet transformation. Simula tion results show ,when transmission bit rate is1.0bpp,PSNR of 9/7 wavelet is 41.557db,PSNR of 5/3 wavelet is 36.50db.Compares with9/7wavelet,PSNR of 5/3 wavelet drops 12.5%.The paper adopts two programs on removingspectroscopy correla tion of hyper-spectral images:DPCM spectral compression and wavelettransform spectral compression. The experimental data shows,using the two programs oncompression of hyper-spectral , PSNR can be both achieved above 40db, when they both at1.0bpp transmission bit rate.But compared,9/7 wavelet has better effect on removingspectroscopy correla tion.PSNR enhance about 1db. This show that the progranm which basedon 9/7 wavelet 3D-SPIHT coding algorithm is much more adapted to the hyper-spectral image compression. |
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