Cone beam CT fast reconstructing method based on minimum three-dimensional convex hull

Abstract

The invention discloses a cone beam CT (Computed Tomography) fast reconstructing method based on a minimum three-dimensional convex hull, comprising the following steps of: collecting one group of projection images through pencil beam CT circular scanning to a test piece, and cutting all the projection images into one group of square projection images of which the side length includes E pixels; calculating the parameters of the minimum three-dimensional convex hull of the test piece in a reconstruction space; calculating the square projection images to obtain one group logarithm images with single-precision floating point type pixel gray values; filtering the logarithm images in an FDK algorithm, performing the voxelization of the minimum three-dimensional convex hull, allocating the reconstructed memory space, preferably reconstructing the algorithm along a Z line and reconstructing voxels in the minimum three-dimensional convex hull by using a single-instruction multiple-data technology; and storing the reconstruction result as sequence sliced images in the X direction, the Y direction and the Z direction according to the coordinate system, and releasing the memory space occupied by reconstruction. The method efficiently increases the reconstruction speed of cone beam CT and lowers the requirements of the reconstruction algorithm for memory size.

Description

technical field [0001] The invention belongs to the field of CT system image reconstruction, and relates to a method for fast reconstruction of CT images based on the smallest three-dimensional convex hull in a cone-beam CT system. Background technique [0002] Computed Tomography (CT) is an imaging technology that obtains internal tomographic image information of the measured object by reconstructing the ray projections from different angles of the object. Cone-beam CT uses a cone-beam X-ray source and an area array detector to collect the projection data of the measured object. Compared with traditional two-dimensional CT, cone-beam CT can reconstruct hundreds or even thousands of tomographic images in one scan. It has the characteristics of high ray utilization rate, continuous slices, the same spatial resolution within and between slices, and high precision. [0003] A key issue in the application of cone beam CT is to improve the image reconstruction speed. At present...

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Problems solved by technology

Zhang Shunli, Zhang Dinghua, Zhao Xinbo and others in the "Journal of Computer-Aided Design and Graphics" (2009, 21(2): 160-164) "Fast CT image reconstruction based on the smallest area" aimed at the linear array parallel beam CT reconstruction method A fast CT reconstruction method based on the minimum area is proposed, which further reduces the calculation amount of reconstruction in 2D CT reconstruction, but this method is not suitable for cone beam CT

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