Three-dimensional measurement with stereo polarization digital image correlation method insensitive to ambient light

The measurement of the external topography and deformation of large industrial equipment is important. Photoelectric measurement technology can quickly obtain three-dimensional (3D) topography information of components and equipment. Among them, stereo digital image correlation (stereo-DIC) is a 3D measurement method which combines binocular stereo vision system and digital image cross-correlation matching technology. This method has many advantages such as non-contact, wide measuring range, high speed and single frame reconstruction. However, this passive optical measurement method is prone to the interference of ambient light and the impact of high reflective surface, resulting in data loss, which limits the application scenarios of this method. This paper proposes a method of 3D reconstruction against ambient light based on stereo polarization digital image correlation (stereo-PDIC). In this method, speckle is generated by a laser beam irradiating a ground glass and is then projected onto the surface of the target. The polarization speckle image in single frame and multiple polarization channels is collected by binocular polarizing cameras. The influence of the reflected stray light and ambient light is eliminated and the contrast of speckle image is improved. Stereo matching of the speckle images with the corresponding angle of polarization captured by the binocular polarizing cameras is carried out, and finally the 3D reconstruction of the target is completed. The feasibility of this method is verified by both simulation and experiment.