The Algorithm Research On ROI Reconstruction Of The CT Images

Computer tomography, is the best one of the non-destructive testing technology, hasbeen widely used in human tissue imaging and industrial non-destructive testing. When weencounter large objects, we only need to analyze a part of the object or check if the part hasproblems, then the ROI reconstruction(also call local reconstruction) is very important at thistime, and this paper has researched ROI reconstruction based on this.This paper firstly analysis the filter function and interpolation function along thealgorithm realized,and reduct the computer implementation process of FBP algorithm.Lastlytranslate the3D cone beam filtered backprojection(BPF) algorithm into parallel beam BPFalgorithm.This paper present ROI reconstruction algorithm based on the BPF algorithm.In orderto realize the reconstruction of ROI, this paper using the BPF algorithm by using the localproperties of differential and limited Hilbert transform. It is an accurate algorithm, firstdifferential the projection data only cover the ROI area, then do back projection to the ROIarea, last do limited Hilbert filter to get the ROI image along the PI line covered ROI area.The simulation demonstrates that BPF and FBP algorithm’s accuracy of wholereconstruction is substantially the same, but BPF algorithm can realize the accurate ROIreconstruction, while the FBP can’t do it by it have not local properties. The paper using aweighted Hilbert transform method in realizing the limited Hilbert transform, since that itcan avoid the bright side of image artifacts effectively.