• Title/Summary/Keyword: On-Machine Mesurement

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Error Analysis of Free-Form Artifact using 3D Measurement Data (3차원 측정 데이터를 이용한 자유곡면 가공물의 오차해석)

  • 김성돈;이성근;양승한;이재종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.439-442
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    • 2001
  • The Accuracy of a free-form artifact is affected by machine tool errors, machining process errors, environmental causes and other uncertainty. This paper deals with methodological approach about machine tool errors that are defined the relationship between CMM and OMM inspections of the free-form artifact. In order to analyze the measurement data, Reverse engineering was used. In other words, Surface of Free-Form Artifact is generated by NURBS surface approximation method. Finally, Volumetric error map is made to compare surface of CMM data with that of OMM data.

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COMPARISON OF IMAGE REFORMATION USING PERSONAL COMPUTER WITH CT SCAN RECONSTRUCTION (CT 스캔 영상재구성과 개인용 컴퓨터를 이용한 영상 재형성과의 비교에 관한 연구)

  • Jung Gi-Hun;Kim Eun-Kyung;Kim Sang-Joon
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.24 no.2
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    • pp.361-368
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    • 1994
  • Radiographic planning is needed for implant placement in order to determine implant length, jaw bone volume, anatomical stucture and so on. Radiographic examination includes conventional radiography, conventional tomography and CT scan. The most accurate mesurement can be obtained from CT scan. For the cross-sectional view of mandible, CT scan reconstruction is generally needed. But the cross-sectional view of mandible can be reformed by personal computer. This study was performed to examine the clinical usefulness of reformed image using personal computer in comparison with CT scan reconstructed image. CT axial slices of 4 mandibles of 4 volunteers were used. Digital imaging system was composed of Macintosh Ⅱ ci computer, high resolution Sony XC-77 CCD camera, Quick Capture frame grabber board and 'NIH Image' program. Seven reconstructed cross-sectional images within CT machine(CT group) were obtained. And seven reformed cross-sectional images(PC group) after digitization of CT axial slices into the personal computer were obtained. PC group was compared with CT group in the objective and subjective aspects. The results were as follow: 1. Measurement of mandibular height & width in both group showed insignificant difference(P>0.05). 2. Subjective assessment of the mandibular canal in both group showed insignificant difference(P>0.05). 3. Image reformation using personal computer could provide panoramic view, which could not be obtained in CT scan reconstruction.

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