Progress in Multi-Physics Optical Diagnostic Technology Based on Light Field Imaging

The development of light-field imaging principles has provided new insights and directions for diagnostic multi-physical fields. The light-field camera, based on the principles of light-field imaging, captures the angle information of incident light rays, through a micro-lens array between the main lens and the sensor. Researchers have developed various multi-physics diagnostic techniques based on the principles of light-field imaging. Firstly, the light-field particle image velocimetry (LF-PIV) technique was introduced. It utilized a light-field camera to capture particle images of a complex three-dimensional flow field. Applying three-dimensional calibration, reconstruction and cross-correlation algorithms subsequently gene-rated the three-dimensional velocity field. It ensures measurement accuracy while capturing a three-dimensional three-component velocity field. Moreover, it effectively reduces the device size for velocity field measurements within constrained spaces. Secondly, the application of light-field cameras in the field of shape measurements was introduced. The light-field camera can capture three-dimensional point cloud information of the object′s surface by a single camera and a single shot. This not only significantly reduces measurement time but also simplifies imaging equipment, enabling three-dimensional topography measurement of film-cooling holes. Thirdly, applying light-field camera in the field of temperature measurement can simplify spectral separation methods, leading to the streamlining of temperature measurement systems. Finally, the light-field multi-physics diagnostic technology was summarized, and the endoscopic light-field and meta-lens-based light-field diagnostic technology was prospected.