A modified Richardson–Lucy deconvolution for rapid reconstruction of light field μPIV

Light field micro-particle image velocimetry (LF-μPIV) can achieve the accurate measurement of the three-dimensional microflow through the high-resolution reconstruction algorithm of tracer particle distribution in measurement volume such as Richardson–Lucy deconvolution (RLD). However, RLD is time-consuming, which significantly lowers the efficiency of the particle distribution reconstruction in LF-μPIV. Considering the sparse characteristic of particle distribution in measurement volume of LF-μPIV, a modified Richardson–Lucy deconvolution (MRLD) is proposed to improve the reconstruction efficiency in this paper. The convolutions of the voxel matrixes in measurement volume and their point spread functions are replaced by the sum of the products of the non-zero voxels in measurement volume and their corresponding point spread function. This greatly eliminates the redundant calculations caused by the zero voxels in measurement volume, and thus effectively decreases the reconstruction time. Further, the applicable condition and appropriate threshold of MRLD are numerically analyzed and determined, and its performance is compared with that of RLD. Experiments are also performed in a rectangular microchannel to verify the feasibility of the proposed MRLD. Results demonstrated that MRLD is more than 2 times faster than RLD to reconstruct the particle distribution with identical reconstruction quality and measurement accuracy in measurement volume.