Pixel -grade image fusion is a comprehensive and analysis of information directly and analyzed by the image signals of each sensor output under strict standards. Pixel -level image fusion is the information fusion of information on the basics. The main task is to integrate the measurement results of multi -sensor targets and background elements. Pixel -level and image fusion is a fusion directly on the original data layer. The fusion accuracy of this level is the highest, and it can provide the richer, more accurate, and more reliable details information that is not available at other levels of integration processing, which is conducive to further analysis, processing and understanding of the image. Pixel -level image fusion is currently the most widely used image fusion method in actual situation, and it is also the basis for the fusion of feature -level image and decision -level image. However, compared with the fusion of the other two levels, the amount of information that needs to be processed in pixel -level fusion is the most person, the processing time is longer, and the requirements for the equipment are relatively high. Before the fusion of pixel -level images, the various images participating in the fusion must be accurately prepared. The accuracy of the standards should generally reach the pixel grade. Therefore, pixel -level fusion is the most complicated and difficult fusion in the image fusion.