Volumetric calibration for scheimpflug light-field PIV

This work presents a volumetric calibration method for Scheimpflug plenoptic camera in particle image velocimetry. To establish a prerequisite foundation for the Scheimpflug light-field PIV, the proposed technique makes use of the unique point-like pattern and plenoptic disc feature of particle light-field images to accurately determine affected pixels for a spatial voxel in a measurement volume. With Gaussian optics, an ideal projection model of the Scheimpflug plenoptic camera is derived to provide a basis for the calibration method. By taking lens defects, optical window's imperfection, inaccurate tilted-angle and other practical application difficulties into account, the calibration method can establish the mapping relationship between a spatial voxel and its affected pixels correctly. The volumetric calibration method was validated by a classic vortex-ring PIV measurement where the correspondence between a voxel and its affected pixels was accurately determined and the volumetric velocity field was successfully acquired.