이미지 보정을 이용한 제한된 환경에서의 디지털 이미지 상관법

Digital Image Correlation (DIC) is a new method of measuring material properties. DIC requires a fixed camera and a separate instrument to acquire images. The measurement position and orientation for the DIC measurement of a workpiece are severely constrained. Therefore, additional devices are required. In this study, only a marker with a grid pattern was attached, and a photograph of a specimen surface was captured without additional equipment. Specimen images were moved and tilted because the camera would shake during the experiment and the camera and specimen were not parallel. The acquired specimen images might be shifted or deformed. Sample images were acquired form various angles and then calibrated with perspective transformation by a developed algorithm and software. Surface strain (or deformation) field data were obtained using the calibrated specimen images and DIC. Therefore, the developed algorithm was verified by comparing the strain field data of the corrected DIC images.