锥束扫描三维CT及其工程应用

Three Dimensional Computed Tomography Based on Cone-beam Scanning and Its Engineering Application

目的介绍了作者基于非晶面阵探测器开展的3D-CT(Theedimensional Compurted Tornography)及基于ICT(IrKhJsnjal Cornpu TOmography)的逆向工程技术R Revase Engineening研究。方法与资料利用具有高分辨率、高；2敏度、高事瞻态范围吲}晶崮鄙车揪啃器开展镭}出瞄3I)．CT研究，采用Fektk~型型程莲建算法，即利用锥即利用锥束射线回转扫描得到的二维数字投影序列重建扫描区域断层图像。在小锥角情况下，重建质量可以与二维cT相美；对三维重建得到的CI'图像进行相直的图像、图形处理，获取实物内外表面轮廓数据，并将其输入CAD设汁平台，逆求出实物原型的CAD模型。结论320KV和9MeV高、低能射线下的重建指标：空间分辨率为2．0-3．0Lp/ma；密度分辩率为03％：基于3D-CT的RE技术寸刊秤携哧结构的快速原型韦啦告、技才、一破泽、改型设讨提供了有力自孵锻，有着十分重要的直用价健和广泛需求前景。

Objective: To introduce the authors research work of 3D-ICT (Three Dimensional Industrial Computed Tomography) and ICT assisted reverse engineering. Methods: On the basis of the amorphous silicon flat panel detector (FPD) with high resolution, sensitivity and wide dynamic range, the cone-beam 3D-ICT is researched. The cone-beam X-ray scans the objects along circle locus and the two dimensional digital projections are captured by the FPD. Then using the projections, the 3D-images are reconstructed, which are almost as good as 2D-CT images when the cone-beam angle is small enough. Through corresponding image and graphics processing methods on the 3D-CT images, the internal and external contours of the object are got and loaded into CAD designing platform. Using the RE module of the software, the CAD model of the physical prototype is finally created. Conclusion: The experimental results on low and high X-ray energy (320KV&9MeV) prove that the image quality of 3D-CT can almost be as good as 2D-CT, the spacial resolution is 2.0-3.0Lp/mm and the contrast resolution is 0.3%. ICT assisted RE is the powerful approach to rapid prototype manufacturing(RPM),technique decoding and remodeling of objects with complicated external and internal surfaces, and will be of important value and wide using foreground.