The analysis of interferometry fringe pattern under shearing quantity and inside pressure change for inspect inside defects using by digital shearography

Digital shearography를 이용한 내부결함 검출에 있어서 전단량과 내부압력 변화에 따른 간섭줄무늬 패턴 분석

Digital shearography, a speckle pattern method is based on the superposition of two laterally sheared images. Therefore, object points which are positioned in some distance from each other are superposed in the image plane. This shearography, one of NDT methods without contact, is able to inspect defects in pipelines and pressure vessels that are used in nuclear power plants. This is can inspect whole fields and has a low sensitivity to environmental noise. Because optical setting is very simple, it has a little exhaustion of time, cost and man power. And also it can find a defect position through real time monitoring of a part. This paper, finds out the relationship among shearing quantity image quality and defect size with this method.