Cone-beam CT Reconstruction Algorithms And Optimization Based On FDK Method

X-ray Computer Tomography (XCT) is refered to as a imaging technology, that it usesX-ray source and detector acquisition angle range of the plurality of projection images of theobject, and then uses the imaging reconstruction algorithm convert the image data into asequence of slices. The cone beam CT has the advantage of high utilization rate of X raytomography image reconstruction, high resolution, fast scanning speed etc, is the directionand hotspot in CT research field. Therefore, the study of cone-beam XCT imaging technologyhas important application value and academic research value.In this paper, according to the theory of CT reconstruction algorithm filter backprojection reconstruction algorithm, for the purpose of improving the quality of imagereconstruction and removing the noise of reconstruction image, so that improving andoptimizing the FDK reconstruction algorithm.In the aspect of interpolation method, according to the process of filtered back projectionreconstruction algorithm, the characteristics of each projection in the detector projectiondistribution, we propose a new weighting interpolation method. The experimental results offan beam filtered back projection reconstruction show that the new interpolation methodcould preserve the image edge details, and also can effectively suppress noise. The improvedinterpolation method is applied to FDK algorithm, also can better preserve the image detailsand lower image noise. In the aspect of improving the FDK algorithm, we proposed aimproved FDK algorithm based on non equiangular scanning, the improved FDK algorithmavoids the disadvantages of FDK algorithm, reduces the requirement of hardware devicesprecision, without compromising the quality of the tomographic image, so the improved FDKalgorithm has high practical value. Finally based on CT reconstruction filter design, weproposed a new hybrid filter, the new filter is applied to the FDK algorithm, the experimentaldata shows that the new hybrid filter improves the similarity and clarity of the reconstructedimage and suppresses noise of the reconstructed image. In addition, we also proposed aquadratic smooth filter to suppresse noise in CT projection data, it has made a goodde-noising effect than the hybrid filter.