探测器偏置重建算法在工业CT检测中的应用

Application of detector offset reconstruction algorithm for industrial CT test

工业CT检测对象的大小是不固定的,最大限度地利用已有探测器的成像面积非常重要。采用探测器偏置来获得更大的扫描视野,并推导相应的重建算法。该算法首先使用Parker类型函数对采集到的投影数据中的冗余部分进行加权,然后采用扇束滤波反投影重建算法重建得到断层图像。在实验中使用实际工业CT系统分别采集钢制线对块与铝合金变速器外壳的投影数据进行重建算法的验证,重建结果证明了使用的探测器偏置重建算法的正确性与有效性,且空间分辨率和标准扫描的重建结果保持一致,这个方法可以在工业CT成像上有效使用。

The detected samples of ICT have variable sizes. Maximizing the imaging area of detector is meaningful. This paper uses detector offset to enlarge the FOV, and derives appropriate reconstruction algorithm. The algorithm uses Parker type function weighted redundant portion of the projection data first, then uses fan-beam filtered backprojection reconstruction algo- rithm to obtain a tomographic image. In experiment, we used an actual industrial CT system to collect projection data of a steel line-to-block and an aluminum alloy gearbox shell to verify the reconstruction algorithm. The reconstructed results prove the cor- rectness and validity of the proposed algorithm, and the spatial resolution is consistent with the reconstructed result of standard scan, and the detector offset method can be used effectively in industrial CT imaging.