The Study Of Single Objective Optimization Image Reconstruction Algorithms

Computer tomography(CT) is widely applied not only in the medicalradiodiagnosis, but also in the industry inspection. Transformation basedimaging technique is generally adopted in the medical CT, because a large numberof projections can be obtained and analytic algorithm is then used to quicklyreconstruct image with high quality. In industry application, however,incomplete projections can only be obtained, so the situation is not appropriateto the transformed imaging technique and then the iterative algorithm has tobe applied so that better reconstructed image can be got. Unfortunately, up tonow, there is no an efficient algorithm to deal with the iterative reconstructionalgorithm, How to balance the quality and the speed of reconstructed image isalways a goal that many investigators pursue.As for single objective optimization algorithm, steepest descent algorithmreconstruct image with the idea of least square .The speed of the steepest descentis slow, so we adopt the conjugate gradient algorithm ,it has not only a propertyof quadratic convergence, but also memorizer is small.In order to express imaging problem accurately, moreover, projectionequations are introduced as the restricted condition of single objectiveoptimization, and then a restricted least-square iteration algorithm for imagereconstruction from projections is adopted to get the reconstructed results withlittle artifact quickly and concisely.The results of all algorithms for image reconstruction from computergenerated projections and real projection have been given in the thesis and thereconstruction results and the subsequent data have shown their validity ofalgorithms.