JAMSTEC Rep. Res. Dev., Volume 8, November 2008, 29 36 X CTm/pixel X CT X CT. -. mol/l KI KI CT CT X CT CT ; - - +- -- hirono@ess.sci.osaka-u.ac.jp
Accuracy check of grading of XCT Report Accuracy check of grading and calibration of CT value on the micro-focus XCT system Tetsuro Hirono Masahiro Nishimura Osamu Tadai and Weiren Lin 3 The micro-focus XCT system is a powerful technique to visualize the inner structure of rocks nondestructively with 2.0μm resolution. Although the XCT image includes some errors resulting from beam hardening, ring artifacts, quantum noise and dependency on the condition of accelerating voltage and current, noise can be reduced by usage in the best imaging conditions. Quantitative treatment is possible in the same conditions with consideration of the cause of the error. We also constructed the transformation from grading on the micro-focus XCT image to a generalized CT value. Keywords : micro-focus XCT, grading, CT number, beam hardening, quantum noise Received 18 July 2008 ; accepted 16 October 2008 1 Department of Earth and Space Science, Graduate School of Science, Osaka University 2 Marine Works Japan. LTD. 3 3Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology Corresponding author: Tetsuro Hirono Machikaneyamacho 1-1, Toyonaka, Osaka, 560-0043, Japan +81-6-6850-5796 hirono@ess.sci.osaka-u.ac.jp Copyright by Japan Agency for Marine-Earth Science and Technology JAMSTEC Rep. Res. Dev., Volume 8, November 2008, 29 36
T. Hirono et al., X CT Computerized Tomography X X X CT X CT X CT Nakashima, CT X CT CT X CT Tsuchiyama et al., X CT X CT CT Central Ray CT Wedge Table X CT ( ) HMX Fig. a kv mx mmi.i. CCD CT Fig. bctlaks Shepp-Logan CT bit TIFF X CT Fig. 1 (a) Micro-focus X-ray CT in the Kochi Core Center. (b) Experimental arrangement of X-ray CT imaging for KI solution. Fig. (a) X CT (b) Table Calibration factors. SID is the distance between target and detector, and SOD is the distance between target and sample. Table SID SOD JAMSTEC Rep. Res. Dev., Volume 8, November 2008, 29 36
Accuracy check of grading of XCT X CT mm X CT/ - kv-a I.I. m/pixel m CT Laks SID SODSIDmm SOD. mmwedge kv A kvakva X CT /X CT / Table kv / kvkv /kv / kv kv kv kv / kv A /. kva /. X CT / mmkv A Table Determination of best conditions of accelerating voltage and current of electron. Table / JAMSTEC Rep. Res. Dev., Volume 8, November 2008, 29 36
T. Hirono et al., kv A X CT Fig. a Fig. a X CTFig. b X X X X X X X X X Fig. a X kv A X CT Fig. a kv A X CT Fig. b Fig. 2 X-ray CT image of cylindrical glass at 80 kv and 80 ºA. (b) Line profile of grading of attenuation of X-ray. Fig. (a) kv Amm X CTb (b) Fig. 3 (a) X-ray CT image of cylindrical glass at 60 kv and 40 μa. (b) X-ray CT image of cylindrical glass at 100 kv and 60 μa. Fig. (a) kv Amm X CT (b) kv A mmx CT JAMSTEC Rep. Res. Dev., Volume 8, November 2008, 29 36
Accuracy check of grading of XCT X X mm wedge wedge X CT Table kva I.I. m/pixel SIDmm SOD. mm (a) wedge /. (b) / m / X X. X... Table Differences of the grading by the condition of imaging. Table JAMSTEC Rep. Res. Dev., Volume 8, November 2008, 29 36
T. Hirono et al., (c) wedge A /Wedge X CT CTCT CT-X CT X CT CT CT X CT.-. mol/l KI X CT X CTRadix- Pratico kv mamm mmct xx CT CTKI Fig. a CT Fig. a. -. mol/l CT KI CT CT.. CT. -. mol/l KI CT.KI. KIKI CT.... mol/l KI X CT I.I. wedge A kva m/pixel m X CT KI Fig. b KI.KI Fig. 4 (a) Relationship between concentration of KI solution and CT value on the medical XCT. (b) Relationship between concentration of KI solution and grading of attenuation of X-ray on the μ XCT. Fig. (a) X CT CTCT (b) X CT JAMSTEC Rep. Res. Dev., Volume 8, November 2008, 29 36
Accuracy check of grading of XCT X X CT CT X CT m/pixel X CT X CT. -. mol/l KI KI CTCT X CT X CT - X CT,, - X p X CT ( )-X CT - - -CT, MRI- p Nakashima, Y. (), Diffusivity measurement of heavy ions in Wyoming montmorillonite gels by X-ray computed tomography, Journal of Contaminant Hydrology, 61, -. X CT,, - Tsuchiyama, A. Nakamura, T., Nakano, T., and Nakamura, N. (), Three-dimensional description of the Kobe meteorite by micro X-ray CT method: Possibility of threedimensional curation of meteorite samples, Geochemical Journal, 36, -. JAMSTEC Rep. Res. Dev., Volume 8, November 2008, 29 36