Sparse angle fast neutron CT imaging method

Abstract

The invention discloses a sparse angle fast neutron CT imaging method. The method comprises: (S1) acquiring projection data of a sample to be measured at a sparse angle by using a fast neutron CT system to obtain a sinogram of a slice layer to be reconstructed, and performing logarithmic transformation processing on the sinogram; (2) reconstructing the projection data by adopting a statistical iterative reconstruction algorithm to obtain a preliminary reconstruction result; (S3) constructing a sparse angle fast neutron CT image reconstruction model; (S4) solving the sparse angle CT image reconstruction model to obtain an image after image total variation optimization; and (S5) repeating the steps (S2)-(S4), stopping calculation when the number of cycles reaches a preset number, and takingan obtained iterative calculation result as a final reconstructed image. According to the method, the noise model can be depicted more accurately, a better reconstructed image is obtained, the scanning time of fast neutron CT is effectively shortened, and the iterative convergence speed is increased. Therefore, the requirements of actual application are better met.

Description

technical field [0001] The invention belongs to the field of ray transmission imaging, and in particular relates to a sparse-angle fast neutron CT imaging method. Background technique [0002] Fast neutron CT has been widely used in the nondestructive testing of hydrogen-containing materials. However, limited by the intensity of the neutron source and the detection efficiency of the detector, the sample scanning time is as long as hours or even days. How to effectively reduce the scanning time under the premise of ensuring the quality of image reconstruction has become one of the key technologies in the field of neutron CT imaging. At present, the common methods to reduce the scanning time include reducing the exposure time of each angle and reducing the projection angle. Reducing the exposure time of each angle will lead to the increase of statistical noise in the projection data, and reducing the projection angle is a sparse angle CT scan. [0003] For sparse-angle CT sc...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a sparse-angle fast neutron CT imaging method, which mainly solves the problem in the prior art that the quality of the reconstructed image is affected by the inaccurate noise model and slow convergence speed.

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