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Image Processing
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Subband SAR Image Coding by using Quadtree Decomposition on Variable Block Truncation Code
(a) Original Tm4. image
(b) 0.8748 bpp ; PSNR 35.6855 dB.
(d) 1.2813 bpp, PSNR = 31.6684
(e) Original sanfran image
(f) 0.9166 bpp, PSNR = 28.2613
(g) 2.8750 bpp, PSNR = 28.1818
Figure 4. (a),(e) Original SAR images , (d),(g) Reconstruction by subband BTC and
(f),(b) Reconstruction by subband VBTC
(h) Original sar3 image
(i) 0.9788 bpp, PSNR = 32.1858
Figure 4. (con't.) (h) Original sar3, (i) Reconstruction by subband VBTC
VI. Conclusions
Subband SAR image coding by using the variable block truncation coding (VBTC) is more efficient than using Fixed Block Truncation code that is reduced the processing time for compression a SAR image. VBTC technique can be classified data in an image into group that is homogeneous in a group of data. Data in each group is divided by QT decomposition, which is optimal for encoding by using VBTC encoder. Disadvantage of VBTC technique is the threshold selection in the quadtree stage. These thresholds are the criterion for dividing the image into block. If we select the maximum threshold which is obtained most large of blocks and a few blocks for coding. We will get the high compression rate, but the low quality of reconstruction image. In other word, reconstruction image is high quality, but low compression rate. Good pre-filter are required to reduce noise before compressive procedure that are obtained high quality of the reconstruction image.
VII. References
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Delp, E. J., and Mitchell, O. R., 1991, Moment Preserving Quantization, IEEE Transactions on Communications, Vol. 39, pp. 1549-1558.
- Delp, E. J., Saenz, M., and Salama, P., 2000, Block Truncation Coding (BTC), Handbook of Image and Video Processing, edited by Bovik A. C., Academic Press, pp. 176-181.
- Long Wen Chang, and Ching Yang Wang, 1999, Image Compression Using Optimal Variable Block Truncation Coding, Multimedia Signal Processing, 1999, IEEE 3rd Workshop on, 1999, pp. 413-418.
- Mohamed Kamel, Sun C. T., and Lian Guan, 1991, Image Compression by Variable Block Truancation Coding with Optimal Threshold, IEEE Transactions on Signal Processing. Vol. 39, No. 1, pp. 208-212.
- Kai-Krung Ma, and Sarah A. Rajala, 1991, Subband Coding of Digital Images Using Absolute Moment Block Truncation, IEEE Transactions on Acoustics, Speech, and Signal Processing, 1991. ICASSP-91., International Conference on, 1991 Vol. 4, pp. 2645-2648.
- Martin Vetterli, and Cormac Harley, 1992, Wavelets and Filter Banks: Theory and Dsign, IEEE Transactions on Signal Processing, Vol. 40, No. 9, pp. 2207-2232.
- Strang G., and Ngnyen T., 1996, Wavelet and Filter Banks, M.A., edited by Wellesley-Cambridge Press, pp. 103-113.
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