High-temperature stereo-digital image correlation using a single polarization camera

We propose a new, to the best of our knowledge, full-frame, single-camera stereo-digital image correlation (stereo-DIC) technique that is capable of measuring surface profile and deformation over a wide temperature range. This technique uses a single polarization camera and a polarizing beam splitter to synchronously capture two full-frame sub-images with orthogonal polarization directions. By further adopting the idea of active imaging that combines monochromatic blue-light active lighting and narrow bandpass filter imaging, this system can capture stable and high-contrast speckle images of specimens at extremely high temperatures. From the captured sub-image pairs, profile and deformation fields can be retrieved using a regular stereo-DIC algorithm. Compared with the existing full-frame single-camera stereo-DIC systems implemented on a color camera, the established system offers wider applicability, since it is insensitive to serious variations in ambient light in non-laboratory environments and to the thermal radiation of hot objects in extreme high-temperature environments. The effectiveness and accuracy of the proposed technique are validated by room-temperature tests and high-temperature tests at up to 1000 degrees C. The advantages of a simple configuration, free synchronization, and full-frame high-temperature deformation measurement ability offer the proposed technique potential in both high-speed and high-temperature 3D measurement applications. (C) 2020 Optical Society of America