Dissertation > Industrial Technology > Automation technology,computer technology > Computing technology,computer technology > Computer applications > Information processing (information processing) > Pattern Recognition and devices > Image recognition device

Research on Data Correction in Computed Tomography

Author GuJianWei
Tutor ZhangLi
School Tsinghua University
Course Nuclear Science and Technology
Keywords Computed Tomography Image Reconstruction Metal artifact correction Backprojection filtering
CLC TP391.41
Type Master's thesis
Year 2006
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CT system, due to the existence of objective factors of the detected object, background environment, the projection data tend to abnormal conditions, such as metal projection value is too large, the noise level high, which makes the reconstructed image full of artifacts or noise, seriously affecting image quality . In order to improve the quality of CT images, the use of various correction algorithm to the projection data correction, so that the reconstructed image is accurate representation of the internal structure of the object, which has important implications for improving the performance of the CT system in medical imaging and nondestructive testing. For the purpose of this article to improve the quality of the reconstructed image of the CT system, starting from the introduction of metal artifact correction method, discussed the performance of the interpolation method of interpolation method. Then focus on metal artifact correction filtered back projection reconstruction algorithm. Then based PI segment backprojection filtering algorithm, and the algorithm discussed several influencing factors and metal artifacts in its correction. In addition, the CT images by using the method of partial differential equations Denoising. First, a brief analysis of existing literature various metal artifact correction method. Interpolation methods have a wide range of applications in the metal artifact correction, and many improved algorithms are based on the interpolation method, so also discussed the performance of several interpolation methods used correction. The next chapter is the focus of this article. In this chapter, the correction for different needs several effective for metal artifact correction method, including the accurate positioning of the interpolated correction based metal projection, wavelet multi resolution interpolation correction, the correction of a nonlinear weighting of the projector and based on the recovery of the correction of the curvature of the projected image. Of these methods will first be described to the background of the method proposed, and then gives the result of the process and artifact correction designed. Finally, the appropriate summary or discussion. This reconstruction algorithms developed in recent years, just about the the backprojection filtering reconstruction of metal artifact correction, first introduced simplified parallel beam backprojection filtering reconstruction algorithm parallel PI segments, and the impact of the effect of the algorithm for the reconstruction Several factors are discussed. Then the algorithm for the reconstruction of metal artifacts analysis and correction. CT image denoising research. First, the source of the noise of the CT image analysis and partial differential equations denoising. Anisotropic partial differential equations of the projection data de-noising and denoising results are discussed.

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