I-Corps: Spectral Computed Tomography for Material Identification and Threat Detection

该I-Corps项目更广泛的影响/商业潜力是能够使用X射线照明以比传统光谱计算机断层扫描（CT）系统更低的成本进行材料表征。光谱CT通过识别物体内部结构的化学成分，帮助从炸弹检测到癌组织识别的应用。提出的方法是基于新引入的彩色X射线过滤器的概念。特别地，它依赖于X射线编码投影和计算算法来规避谱CT系统的许多当前限制，诸如高成本和感测复杂性。不是通过衰减的X射线来测量物体，而是首先通过阻挡或解除阻挡已知图案来在振幅和光谱中对X射线进行编码，从而在X射线测量的路径上有效地创建编码孔径。编码孔径创建低剂量结构化X射线束，而不会影响图像重建质量。其目的是提供一种具有成本效益的解决方案，使用传统的X射线成像系统，并添加彩色X射线滤波器和计算算法，以获得材料特定的图像。光谱CT图像的低成本系统将允许在成本敏感的场地更广泛地部署此类系统。这个I-Corps项目使用跨时间，空间和光谱的结构化照明来询问底层对象并获得编码投影。然后，计算算法结合联合收割机编码的测量结果，以重建用于安全和医疗应用中的诊断和分析的基于材料的图像。广泛的模拟所提出的光谱CT系统和探索的结构化照明模式的最佳架构已被执行。对于CT系统的模拟，该软件被用来模拟X射线源光谱与建议的彩色X射线过滤器，并包括NIST数据库。使用不同的材料进行了模拟，以研究所提出的系统的可行性和性能。研究结果已发表在EL和TL的多个同行评审出版物中。此外，X射线成像试验台的设计做拟议的光谱CT architecturs.This奖项的实验验证反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The broader impact/commercial potential of this I-Corps project is the ability to perform material characterization using X-ray illumination at lower costs than conventional spectral computed tomography (CT) systems. Spectral CT aids in applications ranging from bomb detection to identification of cancerous tissue by identifying the chemical composition of the internal structure of objects. The approach that is proposed is based on the newly introduced concept of colored X-ray filters. Particularly, it relies on X-ray coded projections and computational algorithms to circumvent many of the current limitations of spectral CT systems, such as high costs and sensing complexity. Rather than measuring objects by the attenuated X-rays, the X-rays are first coded in amplitude and spectra by blocking or unblocking a known pattern, effectively creating a coded aperture on the path of the X-ray measurements. Coded apertures create lower-dose structured X-ray bundles without compromising the image reconstruction quality. The aim is to provide a cost-effective solution using conventional X-ray imaging systems with the addition of the colored X-ray filters and computational algorithms to obtain material-specific images. Lower cost systems for spectral CT images would allow a broader deployment of such systems in cost-sensitive venues.This I-Corps project uses structured illumination across time, space, and spectra to interrogate the underlying objects and attain coded projections. Computational algorithms then combine the coded measurements to reconstruct material-based images useful for diagnosis and analysis in security and medical applications. Extensive simulations of the proposed spectral CT system and explored optimal architectures for structured illumination patterns have been performed. For the simulation of the CT system, the software was used to simulate the X-ray source spectrum with the proposed colored X-ray filters and included the NIST database. Simulations using diverse materials have been performed to study the feasibility and performance of the proposed systems. The results have been published in multiple peer-reviewed publications by the EL and TL. Additionally, an X-ray imaging test-bed was designed to do experimental validation of the proposed spectral CT architectures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.