Recent Development of Cone-Beam X-Ray Microtomography at Sunyab

1997 ◽  
Vol 3 (S2) ◽  
pp. 1125-1126
Author(s):  
S.J. Pan ◽  
A. Shih ◽  
W.S. Liou ◽  
M.S. Park ◽  
G. Wang ◽  
...  

An experimental X-ray cone-beam microtomographic imaging system utilizing a generalized Feldkamp reconstruction algorithm has been developed in our laboratory. This microtomographic imaging system consists of a conventional dental X-ray source (Aztech 65, Boulder, CO), a sample position and rotation stage, an X-ray scintillation phosphor screen, and a high resolution slow scan cooled CCD camera (Kodak KAF 1400). A generalized Feldkamp cone-beam algorithm was used to perform tomographic reconstruction from cone-beam projection data. This algorithm was developed for various hardware configuration to perform reconstruction of spherical, rod-shaped and plate-like specimen.A test sample consists of 8 glass beads (approx. 800μm in diameter) dispersed in an epoxy-filled #0 gelatin capsule. One hundred X-ray projection images were captured equal angularly (at 3.6 degree spacing) by the cooled CCD camera at a of 1317×967 (17×17mm2) pixels with 12-bit dynamic range. Figure 1 shows a 3D isosurface rendering of the test sample. The eight glass beads and trapped air bubbles (arrows) in the epoxy resin (e) are clearly visible.

2001 ◽  
Vol 19 (1) ◽  
pp. 117-123 ◽  
Author(s):  
L. LABATE ◽  
M. GALIMBERTI ◽  
A. GIULIETTI ◽  
D. GIULIETTI ◽  
L.A. GIZZI ◽  
...  

High dynamic range, space-resolved X-ray spectra of an aluminum laser–plasma in the 5.5–8 Å range were obtained using a TlAP crystal and a cooled CCD camera as a detector. This technique was used to investigate the emission region in the longitudinal direction over a distance of approximately 350 μm from the solid target surface. These data show that the electron density profile varies by two orders of magnitude with the temperature ranging from about 180 eV in the overdense region to about 650 eV in the underdense region. Accordingly, different equilibria take place across the explored region which can be identified with this experimental technique. Detailed studies on highly ionized atomic species in different plasma conditions can therefore be performed simultaneously under controlled conditions.


1998 ◽  
Vol 5 (3) ◽  
pp. 642-644 ◽  
Author(s):  
J. Y. Huang ◽  
I. S. Ko

A diagnostic beamline is being constructed in the PLS storage ring for measurement of electron- and photon-beam properties. It consists of two 1:1 imaging systems: a visible-light imaging system and a soft X-ray imaging system. In the visible-light imaging system, the transverse beam size and beam position are measured with various detectors: a CCD camera, two photodiode arrays and a photon-beam position monitor. Longitudinal bunch structure is also investigated with a fast photodiode detector and a picosecond streak camera. On the other hand, the soft X-ray imaging system is under construction to measure beam sizes with negligible diffraction-limited error. The X-ray image optics consist of a flat cooled mirror and two spherical focusing mirrors.


Author(s):  
S. Kolokytha ◽  
R. Speller ◽  
S. Robson

This study describes a cost-effective check-in baggage screening system, based on "on-belt tomosynthesis" (ObT) and close-range photogrammetry, that is designed to address the limitations of the most common system used, conventional projection radiography. The latter's limitations can lead to loss of information and an increase in baggage handling time, as baggage is manually searched or screened with more advanced systems. This project proposes a system that overcomes such limitations creating a cost-effective automated pseudo-3D imaging system, by combining x-ray and optical imaging to form digital tomograms. Tomographic reconstruction requires a knowledge of the change in geometry between multiple x-ray views of a common object. This is uniquely achieved using a close range photogrammetric system based on a small network of web-cameras. This paper presents the recent developments of the ObT system and describes recent findings of the photogrammetric system implementation. Based on these positive results, future work on the advancement of the ObT system as a cost-effective pseudo-3D imaging of hold baggage for airport security is proposed.


1997 ◽  
Vol 3 (S2) ◽  
pp. 211-212
Author(s):  
C. M. Waterman-Storer ◽  
E. D. Salmon

We have developed a multi-mode digital imaging system (1-3) which acquires images with a 12 bit cooled CCD camera. A multiple band pass dichromatic mirror and robotically controlled excitation filter wheels provide rapid wavelength selection for epi-fluorescence with DAPI, fluorescein or GFP and X-rhodamine fluorophores while maintaining image registration on the cooled CCD detector. Shutters select illumination either by epi-fluorescence or by transmitted light for phase contrast or DIC. A robotically controlled emission filter wheel in front of the CCD camera inserts an analyzer in the light path for DIC imaging. To maximize fluorescence light intensity, the analyzer is removed and an optical flat of equivalent optical thickness is inserted for fluorescence imaging. A slider is inserted at the field diaphragm position of the fluorescence epi-illuminator to provide in-focus slit and spot targets for 360 nm photoactivation of “caged” fluorophores. The microscope system is robotically controlled and image acquisition and analysis is performed using MetaMorph™ digital imaging software.


1998 ◽  
Vol 5 (3) ◽  
pp. 1088-1089 ◽  
Author(s):  
Norio Watanabe ◽  
Sadao Aoki

The depth resolution of a soft X-ray hologram is much worse than its transverse resolution because a single soft X-ray hologram has a small numerical aperture. To obtain a three-dimensional image, in-line holograms of a specimen were recorded from various directions and reconstructed to obtain two-dimensional projection data. Then, a three-dimensional reconstruction was performed by back-projection of these reconstructed holograms. Three-dimensional images of a tungsten wire of diameter 10 µm and a fossil of a diatom were obtained.


2002 ◽  
Vol 20 (2) ◽  
pp. 223-226 ◽  
Author(s):  
L. LABATE ◽  
M. GALIMBERTI ◽  
A. GIULIETTI ◽  
D. GIULIETTI ◽  
L.A. GIZZI ◽  
...  

High dynamic range, space-resolved X-ray spectra, obtained using a TlAP crystal and a cooled CCD camera as a detector, were used to investigate the electron density and temperature profiles of an aluminum laser plasma with micrometer resolution. The electron density profile retrieved from the measurements is compared with numerical predictions from the two hydrodynamics codes MEDUSA (1D) and POLLUX (2D). It is shown that 2D density profiles can be successfully reproduced by 1D simulations using a spherical geometry with an ad hoc initial radius, leading to similar electron temperature profiles.


2015 ◽  
Vol 48 (6) ◽  
pp. 1943-1955 ◽  
Author(s):  
Antonios Vamvakeros ◽  
Simon D. M. Jacques ◽  
Marco Di Michiel ◽  
Vesna Middelkoop ◽  
Christopher K. Egan ◽  
...  

This paper reports a simple but effective filtering approach to deal with single-crystal artefacts in X-ray diffraction computed tomography (XRD-CT). In XRD-CT, large crystallites can produce spots on top of the powder diffraction rings, which, after azimuthal integration and tomographic reconstruction, lead to line/streak artefacts in the tomograms. In the simple approach presented here, the polar transform is taken of collected two-dimensional diffraction patterns followed by directional median/mean filtering prior to integration. Reconstruction of one-dimensional diffraction projection data sets treated in such a way leads to a very significant improvement in reconstructed image quality for systems that exhibit powder spottiness arising from large crystallites. This approach is not computationally heavy which is an important consideration with big data sets such as is the case with XRD-CT. The method should have application to two-dimensional X-ray diffraction data in general where such spottiness arises.


2021 ◽  
Vol 7 (1) ◽  
pp. 3
Author(s):  
Ginevra Begani Provinciali ◽  
Martin Piponnier ◽  
Laura Oudjedi ◽  
Xavier Levecq ◽  
Fabrice Harms ◽  
...  

The Hartman wavefront sensor can be used for X-ray phase imaging with high angular resolution. The Hartmann sensor is able to retrieve both the phase and absorption from a single acquisition. The system calculates the shift in a series of apertures imaged with a detector with respect to their reference positions. In this article, the impact of the reference image on the final image quality is investigated using a laboratory setup. Deflection and absorption images of the same sample are compared using reference images acquired in air and in water. It can be easily coupled with tomographic setups to obtain 3D images of both phase and absorption. Tomographic images of a test sample are shown, where deflection images revealed details that were invisible in absorption. The findings reported in this paper can be used for the improvement of image reconstruction and for expanding the applications of X-ray phase imaging towards materials characterization and medical imaging.


1991 ◽  
Vol 35 (A) ◽  
pp. 407-413 ◽  
Author(s):  
Atsushi Shibata ◽  
Katsunari Sasaki ◽  
Takao Kinefuchi

AbstractThe Fuji Imaging Plate (IP) is a 2-dimensional detector in which a latent X-ray image is stored as a distribution of color centers on a photostimulable phosphor (BaFBr:Eu2+) screen. It has a large effective area, wide dynamic range and high sensitivity. Thus it has been widely used not only in medical but also in scientific and industrial fields. Particularly in X-ray structure analysis, mainly of proteins, it has been used extensively and achieved good results.On the other hand, few applications have been reported in the field except for structure analysis, in spite of the superior performance of the IP which will give significant advantages in various measurements which have been done using an X-ray film such as electric device and fiber specimen.Therefore we report here the basic performance of R-AXIS II(Rigaku Automated X-Ray Imaging System II), an IP reader made by Rigaku, and some applications of X-ray diffraction measurements using IP.


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