The 3D CT Reconstruction Research To Directly Reconstruct The Structure Characteristics

According to the development of three-dimensional CT Technology and the domestic and abroad demands, relying on the prior knowledge and models of the internal structure of the object, on the study of x-ray image enhancement and scattering restoration, combined with FDK reconstruction algorithm, the three-dimensional high resolution CT reconstruction method to directly reconstruct the characteristics was studied.In the CT reconstruction, the quality depends on the feature extraction of projection images, but many factors will affect their performance from the imaging principle of cone beam CT system.On the introduction of the cone beam data acquisition and scanning, a fractal image enhancement method based on the regional connectivity amendment parameter was raised. The fractal model was firstly constructed and H parameters and fractal dimensions were computed. Considering its sensitivity to noise, the connectivity relationship between the center and ambient gray scale inner the slider windows was used to amend H parameters respectively, and further enhance the image for better results. The simulation results showed that the method can not only stress the edge of smaller gray-ray difference but also be of better noise immunity.The polarization analyzation was used to study the scattering and a new restoration method based on the blind separation was raised. An ICA (Independent Component Analysis) model was firstly constituted based on the radiograph mechanism and the sub-band images in high frequency domain by wavelet transform were utilized as estimating source. We utilized the least mutual information entropy as the criteria for blind separation and deduced to the optimization estimation. The experimental results showed that the method can effectively depress the scattering and improve the contrast. On the analyzing of the traditional three-dimensional CT reconstruction, based on the circular scanning, combined with FDK algorithm, a new 3D industrial CT reconstruction algorithm to directly reconstruct the characteristics was brought forward, and the feasibility of the new algorithm was theoretically deduced. Using the fundament of the new algorithm, contacted with the traint of the wavelet before and after RADON, it was deduced to use 2-D wavelet transform to extract the characteristics, and the characteristics were directly reconstruct in the 3D CT to obtain the interested parts. From the generability and multi-characteristics reconstruction EMD was applied in the theory and implementation of three-dimensional CT reconstruction. And an optimal EMD decomposing control method was proposed based on the combination of information entropy and PSNR, and further experimentally verified. The experiment results showed that the CT reconstruction method based on EMD can effectively reconstruct a variety of characteristic information of the original image. By the comparison with the related algorithms, the new method is proved of better preservation to the high frequency information, stronger resistance to noise, easier filter design and shorter time-consuming.