Symmetric Structure Application In Image Reconstruction Iterative Algorithm

The Computerized Tomography (CT) is an important branch of Image Processing. It contains basic research of mathematics theory and is related to actual applied domains. In recent years, CT has been widely applied in many fields such as medical diagnosis, industrial non-destructive testing, agriculture and forestry, physical geography and environmental protection.CT Image Reconstruction includes the analytic method and iterative method. The analytic method is fast and good quality, but request projection data is complete. The algebraic method partitions the basic formula firstly. And then transform the analytic method into algebraic equation set. The algebraic method is simple, and also may process incomplete data.There exists geometric symmetric structure between project radials in the discrete model. This structure is independent of pixel value and the density distributing of object. Symmetric block iterative algorithm technique (SBIRT) was produced when the symmetric structure is applied in algebraic algorithm. Symmetric block iterative algorithm technique changed iterative mode and order of the traditional algorithm, sped up the reconstruction speed, and improved the quality of images.In this paper, we bring the symmetric block structure into dynamic flabby coefficient and radon iterative, produce symmetric block dynamic flabby coefficient and symmetric block radon iterative which change the line-by-line iterative mode. Meanwhile, aiming at the boundary dimness we put forward pixel analyze to confirm the boundary. At the point of boundary we adopt different flabby coefficient to make the borderline more clearly.We use actual data and simulated data to experiment by the method of symmetric block dynamic flabby coefficient technique, symmetric block random iterative and pixel analyze. Compare the reconstructed images by our methods and traditional methods, and make analyze of evaluate parameter. The result indicates that the improved algorithms not only increase the reconstruction speed but also improve the reconstruction precision.