A pre-recognition SART algorithm for the volumetric reconstruction of the light field PIV. (August 2021)

• Record Type: Journal Article
• Authors: Zhu, Xiaoyu; Wu, Zhian; Li, Jian; Zhang, Biao; Xu, Chuanlong
• Is Part Of: Optics and lasers in engineering. Volume 143(2021)
• Publication Date: 2021-08
• Subjects: Light field PIV -- Volumetric reconstruction -- Weight matrix -- Elongation effect -- Pre-recognition SART algorithm; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2021.106625
• Languages: English
• ISSNs: 0143-8166

Abstract

Highlights: An efficient pre-recognition SART algorithm is proposed to address the challenges in the volumetric reconstruction of the light field PIV, including the severe particle depth elongations and the heavy computational cost. The crucial pre-recognition indices of the proposed method are optimized for better reconstruction result and higher reconstruction efficiency. A flexible cage-typed light field camera is precisely assembled for conducting LF-PIV experiments. Abstract: As a novel volumetric velocimetry technique, the light field particle image velocimetry (LF-PIV) based on a single light field camera benefits from its single perspective configuration and has great potential applications in the space-constraint flow measurements. However, the severe particle elongation effects and relatively heavy computational load in the volumetric reconstruction of the tracer particles limit the practical applications of the LF-PIV. To address these issues, a pre-recognition method for optimizing the weight matrix in the volumetric reconstruction of LF-PIV is proposed in this work. The crucial pre-recognition indices significantly influencing the reconstruction accuracy and efficiency are investigated using the synthetic light field images. The feasibility of the pre-recognition-based SART (PR-SART) algorithm is further experimentally validated through the reconstructions of a light source and the measurements of the horizontal laminar flow using an assembled cage-typed light field camera. The results indicated that the PR-SART algorithm is capable of mitigating the elongation effects of the reconstructed tracer particles at different depths and improving the measurement accuracy of the instantaneous velocity field. Additionally, the computational efficiency of the PR-SART algorithm is 4 times faster than the conventional SART algorithm, while the required memory is only 1/5 of the latter.