Simultaneous in-and-out-of-plane deformation measurements using speckle projection and fluorescent digital image correlation

Abstract

A new method for measuring in-and-out-of-plane deformation using a single 3CCD color camera is proposed.First, print a layer of black primer on the surface of the tested object.Then use the spray gun to make red fluorescence on the surface of the tested object.Finally, use the projector to project the computer-generated blue speckle pattern with black primer onto the surface of the tested object, and capture the reference pattern and the deformed pattern with a color camera at the same time.This method uses three independent red-green-blue chips on the 3CCD color camera sensor to separate the captured patterns,the in-plane deformation is measured by Fluorescent Digital Image Correlation (FDIC), and the out-of-plane deformation is measured by Speckle Projection Profilometry(SPP).Compared with the traditional 3-Dimensional Digital Image Correlation(3D-DIC), this method only uses one color image to contain in-and-out-of-plane deformation information , and does not need complex stereo calibration, which greatly reduces calculation workload.Experimental results of step rigid body translation、 disc center loading and free end loading of cantilever beam demonstrate that the proposed technique is easy to implement and can be applied to practical in-and-out-of-plane deformation measurement with high accuracy in engineering field.