Calibration method of turntable rotation center of industrial CT system in offset scanning mode

Abstract

The invention provides a bias scanning mode industrial CT system rotating table rotating center calibration method, which comprises the following steps of according to the initial step length, uniformly installing a plurality of detector nodes at a real detector; obtaining the corresponding relationship of the detector unit on a virtual detector corresponding to the current node on the real detector and the detector unit on the real detector; obtaining a test sinusoidal chart according to the original sinusoidal chart and the corresponding relationship; calculating the center estimation valuecorresponding to the test sinusoidal chart; regulating the current node according to the preset step length increment; repeating the steps until the distance between the current node and the left endpoint of the real detector is not smaller than a preset threshold value after the regulation; using the detector node corresponding to the smallest center estimation value as a rotating center. The problem of the bias scanning mode rotating table rotating center calibration is solved; in addition, a special calibration model body is not needed by the calibration method; the method is simple and convenient; by setting the solving step length in the solving process, the solving precision of the provided method is controllable.

Description

technical field [0001] The present invention relates to the field of CT technology, and more particularly, to a method for calibrating the rotation center of a turntable of an industrial CT system in an offset scan mode. Background technique [0002] At present, CT (Computed Tomography, computerized tomography) is a non-destructive testing method that uses the projection information of objects under different viewing angles, combined with image reconstruction algorithms, to obtain internal quality status and structural information of objects. The marine field has a wide range of applications. [0003] figure 1 It is a schematic diagram of fan-beam CT offset scanning mode in the prior art, figure 2 It is a schematic diagram of the fan-beam CT offset scanning mode in the prior art, such as figure 1 with figure 2 As shown, when performing standard fan beam scanning, the radiation source 1 emits fan beam rays 2, and the scanned slice 3 rotates around the rotation center 4 ...

AI Technical Summary

Problems solved by technology

And because the sinogram obtained by the offset scanning mode is unilaterally truncated, it is difficult to achieve fast and accurate calibration of the projection position of the rotation center by conventional methods

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