Investigation and application of digital image correlation technology in vibration measurement based on two cameras

Abstract

There are many methods for vibration and modal testing. With the development of digital technology and 3-D imaging technology, the development and application of digital image correlation (DIC) technology becomes possible. Now we can use stereo digital image correlation and dynamic photography to obtain data on the structure mode. It should be noted that this is a noncontact measurement technique, meaning there will be a wide range of applications. In addition, the visualization of vibration modes provides the intuitive pictures. This paper focuses on how to build a test environment. The project uses BUMBLEBEE binocular stereo cameras to shoot the images of test object. The images then are transferred, stored, and processed to get the relative coordinates of each pixel. After that, a MATLAB program is developed to revert the coordinates of every pixel, reduce noise, and generate stereo images. The stereo images can be animated based on the timestamps they were acquired. As for data processing, this paper studies the effects of various parameters, such as shutter speed, exposure, gain, vibration frequency and amplitude. The relationship between these parameters and the accuracy of pixel coordinates is studied.