Research On The Artifact From Detector Crosstalk In Industrial CT Image

Industrial Computed Tomography is recognized as a very important nondestructive method. In the process of further studying and extensive using of this technology, there are many problems need to be in-depth researched and resolved. Researching on the crosstalk artifact of industrial CT detector system is one of the hot spot. Studying the range of the crosstalk, the influence factors of detector crosstalk, the effect to the CT image and finding the method to reducing crosstalk artifact has an important value in application and academic research.The main research of this paper is constructed by three aspects. Firstly, the type of crosstalk can be divided into uniform crosstalk, module borders crosstalk which are simulated by Monte carlo method based on the mechanism of detector system. Secondly, the influence of crosstalk to the CT images is researched. At last, the three popular methods which are used to restrain the crosstalk are researched and the two of those three types are simulated.According to the acquiring the spectrum of x-ray form 80keV~650keV by using EGSnrc software, it provides source file for the experiment simulations. Bases on the low-energy x-ray CT system 300BXR, it provides the modules input file for the experiment simulations by the detector system modules program. On the basis of those two simulations model of crosstalk, the CT images are reconstructed respectively. The experiment result shows that crosstalk is not only reducing the spatial resolution of CT image, but also causing the strip and ring artifacts in the CT image.The simulation experiment is respectively based on the factors of x-ray energy, the distance between collimator to the detectors, the different irradiated area and the thickness of the object. The relations of those factors influencing the crosstalk are researched in this paper. It provides some references to the designing of CT detector and the crosstalk artifact correction.At last, the three suppression ways to the crosstalk are presented. The first method is adding isolated layer to decrease the crosstalk. The second way is correcting the crosstalk by measuring the crosstalk rate. The last method is calibrating the crosstalk artifacts in the CT image. This paper analyses the merit and demerit of the three methods, and simulates the first two approaches to restrain the crosstalk artifacts. The result shows that the spatial resolution is raised and the crosstalk artifacts are decreased.