Resolution analysis on light-field particle image velocimetry

Abstract

With rapid developments in light-field particle image velocimetry (LF-PIV) based on single-camera, dual-camera, and dual-camera with Scheimpflug lenses, comprehensive quantitative analysis and careful evaluation of their theoretical spatial resolutions are essential to guide their practical applications. This work presents a framework for and better understanding of the theoretical resolution distribution of various optical field cameras with different amounts and different optical settings in PIV. Based on Gaussian optics principles, a forward ray-tracing method is applied to define the spatial resolution and provides the basis of a volumetric calculation method. Such a method requires a relatively low and acceptable computational cost, and can easily be applied in dual-camera/Scheimpflug LF-PIV configuration, which has hardly been calculated and discussed previously. By varying key optical parameters such as magnification, camera separation angle, and tilt angle, a series of volume depth resolution distributions is presented and discussed. By taking advantage of volume data distributions, a universal evaluation criterion based on statistics that is suitable for all three LF-PIV configurations is hereby proposed. With such a criterion, the pros and cons of the three configurations, as well as the effects of key optical parameters, can then be quantitatively illustrated and compared, thus providing useful guidance on the configuration and optical parameter selections in practical implementations of LF-PIV.