| Project/Area Number |
13680561
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
プラズマ理工学
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| Research Institution | UNIVERSITY OF THE RYUKYUS |
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Principal Investigator |
CHEN Yen-Wei University of the Ryukyus, Faculty of Engineering, Professor, 工学部, 教授 (60236841)
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| Co-Investigator(Kenkyū-buntansha) |
HIGA Hiroki University of the Ryukyus, Faculty of Eng., Research Associate, 工学部, 助手 (60295300)
NAKAMURA Ikuo University of the Ryukyus, Faculty of Engineering, Professor, 工学部, 教授 (40128492)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Penumbral imaging / Hard x-ray / Radiological imaging / Heuristic method / SN ratio / Coded aperture imaging / Tomographic resolution / Three-dimensional imaging / ヒューリスティック法 / ヒューリスティク手法 |
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| Research Abstract |
Recently, many researches have been focused on laser fusions and laser-matter interactions using ultra-short high intensity laser pulse. Imaging of hard x-ray (higher than 10keV) is an important issue for diagnostics of the plasma generated by the ultra-short high intensity laser pulse. To date, the penumbral imaging has been demonstrated as a powerful technique for imaging of penetrating radiations such as hard x-ray and neutrons. Limitations of the penumbral imaging are that it is sensitive to the noise contained in the penumbral images and it do not have any tomographic resolutions.
In order to overcome above limitations, we proposed a heuristic method for robust reconstruction and a coded penumbral imaging technique based on a m-sequence. It is possible to obtain a coded penumbral image with high SN ratio and tomographic resolution by the use of coded penumbral apertures. The main results are summarized as following:
(1) We proposed a heuristic reconstruction method, which is very ro
… More
bust and tolerant to the noise contained in the penumbral images. The method has been applied for measurements of laser-produced plasma density. The results have been published in Rev. Sci. Instrum. (Ref. 4).
(2) We proposed a heuristic blind reconstruction method. It is now possible to reconstruct the source image from the penumbral images alone. The proposed method has also been applied to real laser fusion experiments. The results have published in Rev. Sci. Instrum. (Ref. 3).
(3) We proposed a heuristic method for 3D image reconstructions from three pinhole images. The proposed method has also been applied to real laser fusion experiments. The results have been published in Rev. Sci. Instrum. (Ref. 1).
(4) We newly proposed a coded penumbral imaging technique based on m-sequence. It is possible to obtain a coded penumbral image with high SN ratio and tomographic resolution by the use of coded penumbral apertures. The results will be submitted to Rev. Sci. Instrum.
(5) We quantitatively estimated the tomographic resolution of m-sequence and shown that the tomographic resolution can be improved by use of the fine sampling. The results have published in Rev. Sci. Instrum. (Ref. 2).
(6) We proposed a new heuristic algorithm for three-dimensional image reconstruction from coded aperture images based on simulated annealing (SA). It has been shown that the reconstructed tomographic images can be significantly improved by using the proposed method. We also proposed a fast algorithm to reduce the large computation cost of the heuristic algorithm. Less
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