Three-dimensional digital image correlation using a single color-camera

Abstract

Three-dimensional Digital Image Correlation is typically done using two cameras that view the measured object from differing oblique directions. The measured images are independent and must be spatially connected using a detailed calibration procedure. This places a large demand on the practitioner, the optical equipment and the computational method. A novel approach is presented here where a single color-camera is used in place of multiple monochrome cameras. The color-camera measures three independent Red-Green-Blue (RGB) color-coded images. This feature greatly reduces the scale of the required system calibrations and spatial computations because the color images are physically aligned on the camera sensor. Out-of-plane information is obtained by triangulation using oblique illumination from separate colored light sources. The 3-D Digital Image Correlation is completed by combining the 2-D correlations for each RGB color. An example apparatus is described and some typical results are presented.