A brief review of the photoelasticity based on a pixelated polarization camera: principle, advantages/disadvantages and typical applications

An innovative form of photoelasticity, based on pixel polarization cameras, is rapidly advancing. This paper offers a comprehensive introduction to its operational principles, highlighting key technical advantages such as high-speed and quantitative testing capability, high sensitivity, robust resistance to environmental light interference and a straightforward structure conducive to implementation in industrial settings. Four application examples are provided to demonstrate these advantages. The first two are about dynamic and quantitative stress evaluation, the third one is on-site strength evaluation of tempered glass around the bolts in a confined space, the last one is measurement of Micro-Electrical-Mechanical-System (MEMS) stress birefringence field. In order to provide readers with a more comprehensive understanding of the technology, two primary drawbacks of the new photoelasticity are also addressed. The first is the manufacturing deviation of the nano-grating polarizer, which introduces an additional error factor that necessitates complex corrective measures for high-precision testing. The second is the method's limited measurement range, which requires the use of a multi-wavelength or Red-Green-Blue (RGB) method for unwrapping under large-range conditions. Up-to-date research regarding error correction and phase unwrapping of the novel photoelasticity are briefly introduced, some potential application directions are also introduced.