Journal of X-Ray Science and Technology - Volume 16, issue 4

Authors: Yan, Guorui | Tian, Jie | Zhu, Shouping | Dai, Yakang | Qin, Chenghu

Article Type: Research Article

Abstract: Three dimension Computed Tomography (CT) reconstruction is computationally demanding. To accelerate the speed of reconstruction, Application Specific Integrated Circuit (ASIC) or Field Programmable Gate Array (FPGA) has been used, but they are expensive, inflexible and not easy to upgrade. The modern Graphics Processing Unit (GPU) with its programmable features improves this situation and becomes one of the powerful and flexible tools for 3D CT reconstruction. In this paper, we implement Feldkamp-Davis-Kress (FDK) …algorithm on commodity GPU using an acceleration scheme. In the scheme, two techniques are developed and combined. One is cyclic render-to-texture (CRTT) which saves the copy time, and the other is the combination of z-axis symmetry and multiple render targets (MRTs), which reduces the computational cost on the geometry mapping between slices to be reconstructed and projection views. Our algorithm performs reconstruction of a 512^{3} volume from 360 views of the size 512 × 512 about 5.2s on a single NVIDIA GeForce 8800GTX card. Show more

Keywords: Computed tomography, GPU, CRTT, symmetry, cone-beam reconstruction, FDK

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 4, pp. 225-234, 2008

Authors: Chen, Sharon | Lyon, Alan | Kirz, Janos | Seshadri, Srivatsan | Feng, Yan | Feser, Michael | Sassolini, Simone | Duewer, Fred | Zeng, Xianghui | Huang, Carson

Article Type: Research Article

Abstract: An absolute efficiency measurement technique for Fresnel zone plates using an electron impact micro-focus laboratory X-ray source (Lα line of Tungsten at 8.4 KeV) is demonstrated. A quasi-monochromatic x-ray image of a zone plate was obtained employing a pair of copper and cobalt filters. Applying the method to a gold zone plate with 70 nm outermost zone width, 160 μm diameter, and 660 nm zone height, the absolute first order efficiency was measured to be …8.7% ± 0.6%, which is 73% of the theoretically calculated value. Show more

Keywords: Zone plate, Fresnel zone plate, efficiency, absolute efficiency, laboratory X-ray, filter, X-ray microscopy

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 4, pp. 235-241, 2008

Authors: Yu, Hengyong | Ye, Yangbo | Wang, Ge

Article Type: Research Article

Abstract: The state-of-the-art technology for theoretically exact local computed tomography (CT) is to reconstruct an object function using the truncated Hilbert transform (THT) via the projection onto convex sets (POCS) method, which is iterative and computationally expensive. Here we propose to reconstruct the object function using the THT via singular value decomposition (SVD). First, we review the major steps of our algorithm. Then, we implement the proposed SVD method and perform numerical simulations. Our numerical …results indicate that our approach runs two orders of magnitude faster than the iterative approach and produces an excellent region-of-interest (ROI) reconstruction that was previously impossible, demonstrating the feasibility of localized pre-clinical and clinical CT as a new direction for research on exact local image reconstruction. Finally, relevant issues are discussed. Show more

Keywords: Computed tomography (CT), truncated Hilbert transform (THT), singular value decomposition (SVD), regularization, local image reconstruction

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 4, pp. 243-251, 2008

Authors: Li, Xiezhang | Zhu, Jiehua

Article Type: Research Article

Abstract: The line projection with a lattice of points and the strip projection with a lattice of cells are popularly used in modeling the raw detector reading in discrete tomography (DT). In the strip-based projection model for a 2D rectangular region, the projection equations are formulated according to the fractional areas of the intersection of each strip-shaped beam and the rectangular grid of an image. We propose, in this paper, a scheme to formulate a real system …of linear equations for the strip-based projection model and to convert it into a binary linear system. Thus all the existing reconstruction algorithms for the line-based projection model in DT can be accordingly adapted. Numerical examples are given to illustrate our algorithm. Show more

Keywords: Discrete tomography (DT), strip-based projection, matrix operations

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 4, pp. 253-260, 2008

Authors: Bi, Kun | Liu, Qian | Lv, Xiaohua | Luo, Qingming | Zeng, Shaoqun

Article Type: Research Article

Abstract: This article introduces a driver design of the X-ray flat panel detector which is based on the LabVIEW. The functions in the flat panel detector c code software development kit are classified firstly. And then these classifications are encapsulated into VI modules with some intelligent processing, which described detailedly in this article. Exemplified by the digital ray imaging system, the installation of the system, the implementation of the various functional modules, the procedures to develop the …framework of entire application software and the improvement of the error messages are described in this article. The high performance demonstrated by the imaging results indicates that the controlling and collecting system based on virtual instrument is able to satisfy the requirements of scientific research and the development of prototype machine and software. Show more

Citation: Journal of X-Ray Science and Technology, vol. 16, no. 4, pp. 261-268, 2008