X射线显微三维分层成像的关键理论和技术研究

With the rapid development of electronic products on both integration and precision, it is more and more difficult for the traditional x-ray imaging technique to meet the detection requirements of electronic products, including multi-layer PCB packaging detection, BGA soldering SMT testing, IC chip bonding defect detection, through-silicon process testing, high-density packaging electronic components testing, etc. Therefore, it is urgent to develop a high-performance equipment of x-ray three dimensional microscopic computed laminography to meet the application requirements. Eliminating inter-layer aliasing caused by incomplete projections is the core problem of x-ray three-dimensional microscopic computed laminography. In addition, the large FOV of sample scanning, image metal artifact correction, image distortion correction, image geometric artifact correction as well as data processing and image reconstruction acceleration are also the key techniques for the development of the x-ray three dimensional microscopic computed laminography. On the basis of our previous research on the relevant theories and techniques as well as the development of a prototype, we will delve into the core problems mentioned above, and strive to achieve international advanced results，to support the high performance equipment development and applications of x-ray three-dimensional microscopic computed laminography.

随着电子行业产品的集成度、精密度越来越高，传统X射线显微透视成像技术因影像重叠，已难以满足多层PCB板检测、BGA焊接等SMT检测、IC芯片焊接缺陷检测、硅通孔工艺检测、高密度封装电子元器件检测等应用需求，迫切需要研发高性能的X射线显微三维分层成像检测设备。消除不完全投影引起的重建图像层间混叠是X射线显微三维分层成像的核心难题。此外，样品大视野扫描成像、图像金属伪影校正、图像CT值畸变校正、图像几何伪影校正、数据处理和图像重建加速等也是X射线显微三维分层成像的关键技术。本项目组将在本团队前期相关理论技术成果以及样机研发基础上，深入研究上述成像关键理论和技术问题，力争取得一批国际先进的研究成果，以支持高性能X射线显微三维分层成像检测设备研制和应用。

本项目研究的X射线三维分层成像问题，属于一类特殊的扫描角度不完全的CT成像问题（或有限角CT成像问题），具有广泛和重要的应用背景。该问题的主要困难在于要消除或降低因扫描角度不完全而导致的图像层间混叠伪影，从而改善重建图像的轴向空间分辨。项目组针对板状电子产品检测成像应用需求，研究了X射线显微三维分层成像的关键理论和技术，基本实现了本项目预定的研究目标。主要成果包括：理论方面，项目组提出了两类新的分层CT成像优化模型及其图像重建迭代算法，有效降低了因扫描角度不完全而导致的图像层间混叠伪影；技术方面，项目组针对板状物分层CT成像，设计了几类快速扫描模式，提出了相应的图像几何伪影和射束硬化伪影校正方法；应用方面，项目组与企业联合研发了针对PCB在线检测的三维分层成像设备样机，并交付用户试用。本项目成果对于促进该领域国产设备技术进步，打破国外设备垄断有重要意义。项目组后期将继续针对典型应用，研究重建算法加速方法，改进分层成像设备性能指标。