Research And Implementation On Compression Coding Algorithm Of Identification Pictures

Personal identification picture is a kind of special picture, so it is proverbially existed in all kinds of the fields which we lives in. With the corresponding technology development and the updating of identity management system, new generation of information-stored identity card came out, such as 2-dimension bar code and IC card. But those capacities are limited. In order to store the picture, name, sex, nation and other information in a 2-dimension bar, the compression of identification picture has been a pivotal technology of new generation identity card.The traditional EZW coding compresses the whole picture, so the compression quality and visual effect of personal identification picture are too bad to recognize. In view of visual effect and significance of different regions, the program divides the whole picture into three parts: rectangle of ROI, background region and profile region. In this paper, 1-inch personal identification pictures are taken as compressing object. Researching work includes EZW coding, the implementation that the program uses the run-length coding or straight-line fitting coding to compress the original profile code and the batch processing ways that the program segments personal identification pictures from the scanned picture and saves them as individual pictures for the coding program. Firstly, the theory of wavelet and ROI is introduced, and then the implementation of Mallat algorithm of wavelet is analyzed in detail. The program implements the method that EZW coding integrates with run-length coding and straight-line fitting coding respectively on Visual C++ 6.0 platform. In order to eliminate the redundancy, the program compresses the profile code, which improves the quality of the identification pictures. The experiment verifies that the performance and effect of compression are satisfying. Therefore, the second-generation identification picture can be used the method for reference.Firstly, image compression's theory, significance and background of thesis' selection and the main research are introduced. The main research includes the content, method and technology. Then wavelet theory, EZW coding, ROI coding are introduced briefly. How to implement ROI coding in the algorithm framework ofEZW coding is discussed in this part. At the next part, the procedure that segments personal identification pictures from the scanned image and the method of compressing personal identity picture are explained in detail, and then the experimental results are given. This part includes: implementation of segmenting program, the whole designation of compression algorithm, segmentation of ROI, implementation of wavelet's transformation, silhouette's run-length coding and straight-line fitting coding and experimental results. Finally, all the research work in this paper is summarized and the prospect about the future researching direction is discussed in brief.