title: A dynamic material discrimination algorithm for dual MV energy X-ray digital radiography.
abstract: Dual-energy X-ray radiography has become a well-established technique in medical, industrial, and security applications, because of its material or tissue discrimination capability. The main difficulty of this technique is dealing with the materials overlapping problem. When there are two or more materials along the X-ray beam path, its material discrimination performance will be affected. In order to solve this problem, a new dynamic material discrimination algorithm is proposed for dual-energy X-ray digital radiography, which can also be extended to multi-energy X-ray situations. The algorithm has three steps: α-curve-based pre-classification, decomposition of overlapped materials, and the final material recognition. The key of the algorithm is to establish a dual-energy radiograph database of both pure basis materials and pair combinations of them. After the pre-classification results, original dual-energy projections of overlapped materials can be dynamically decomposed into two sets of dual-energy radiographs of each pure material by the algorithm. Thus, more accurate discrimination results can be provided even with the existence of the overlapping problem. Both numerical and experimental results that prove the validity and effectiveness of the algorithm are presented.
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China; Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, People's Republic of China. Electronic address: lliang@tsinghua.edu.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Ruizhe
authors.initials: R
authors.lastname: Li
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China; Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, People's Republic of China.
authors.forename: Tiao
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, People's Republic of China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Chen
keywords: Dual energy; Material decomposition; Material discrimination; Materials overlapping; X-ray radiography