Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Development of Signal Processing Technique of Digital Speckle Tomography for Analysis of Three-Dimensional Density Distributions of Unsteady and Asymmetric Gas Flow

비정상 비대칭 기체 유동의 3차원 밀도 분포 분석을 위한 디지털 스펙클 토모그래피 기법의 신호 처리 기술 개발

  • Baek, Seung-Hwan (School of Mechanical Engineering, Sungkyunkwan University) ;
  • Kim, Yong-Jae (School of Mechanical Engineering, Sungkyunkwan University) ;
  • Ko, Han-Seo (School of Mechanical Engineering, Sungkyunkwan University)
  • 백승환 (성균관대학교 대학원 기계공학과) ;
  • 김용재 (성균관대학교 대학원 기계공학과) ;
  • 고한서 (성균관대학교 대학원 기계공학과)
  • Published : 2006.04.30
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Abstract

Transient and asymmetric density distributions of butane flow have been investigated from laser image signals by developed three-dimensional digital speckle tomography. Moved signals of speckles have been captured by multiple CCD images in three angles of view simultaneously because the flows were asymmetric and transient. The signals of speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays fur density gradients. The three-dimensional density fields have been reconstructed from the fringe shift signal which is integrated from the deflection angle by a real-time multiplicative algebraic reconstruction technique (MART).

3차원 디지털 스펙클 토모그래피를 개발하여 레이저 영상 신호로부터 비정상, 비대칭 부탄 유동의 밀도분포를 분석하였다. 이러한 유동 해석을 위해 3가지 각도에서 CCD 영상으로부터 스펙클의 이동 신호를 획득하여 유동이 없을 때와 있을 때의 스펙클 변화를 상호 상관법에 의해 계산하였다. 이 때 스펙클의 이동 신호는 유동의 밀도 구배에 따라 굴절각으로 변환될 수 있다. 그 굴절각을 적분하여 광선의 주름 변이를 얻고 이로부터 실시간 곱셈산술재건법(MART)을 이용하여 부탄의 3차원 밀도장 재건을 수행하였다.

Keywords

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