Infrared Image Compression Algorithm

As an important method of opto-electronic imaging, infrared technology plays an important role in military detection and civilian technology field. Efficient transmission of infrared images is a very important research topic both at home and abroad. And image compression is the key in efficient image data transmission. The characteristics of infrared image are analyzed in this dissertation combined with the thermal imaging theory. Based on histogram research, image enhancement and compression algorithms which are applicable to infrared images are presented. Specific experiments on infrared images are carried out. The main contents are as follows.Based on enhancing infrared images using adaptive piecewise linear transform algorithm, a new unsharp mask algorithm which is based on adaptive piecewise linear transform was presented. The contrast of infrared images as well as the image details was improved.Basic encoding methods were studied from the aspects of fidelity, compression ratio and compression speed. Some lossless compression methods were programmed and analyzed in the aspect of fidelity. In the aspect of compression ratio, simple gray-scale quantization was discussed and the run-length encoding was improved. In the aspect of compression speed, WNC algorithm based on binary index tree was studied and the experiment results were compared with the results from the original algorithm.Based on the study of basic encoding methods, an improved infrared image compression algorithm based on embedded zerotree wavelet was presented. In the improved algorithm, the data in the low-frequency sub-band was compressed using lossless compression methods. And the data related to edge was protected. The results showed that the quality of the reconstructed images was improved and the edge details of the reconstructed images were clearer. Since the edge details are usually more valuable in infrared images, the quality of the reconstructed infrared images is the key in image compression on condition that certain compression ratio can be reached. The experiment results showed that the proposed algorithms for infrared image compression were feasible.