Plenoptic particle image velocimetry (PPIV) has been demonstrated in the past as a viable single-/dual-camera technique for 3D flow measurements. Compared to established four-camera tomographic-PIV and 3D-PTV, PPIV has the advantages of lower cost, a simpler setup with a smaller footprint, a deeper depth-of-field for a given aperture and potential for access to otherwise optically restricted facilities. However, because camera bodies must be significantly modified to accommodate an embedded plenoptic microlens array (MLA), past PPIV implementations have been limited to <5 Hz low-speed Imperx cameras. The mitigation of this shortcoming through the development of a modular plenoptic adaptor is hereby presented. The developed adaptor, which consists of an externally mounted MLA and a pair of relay lenses, attaches to and enables plenoptic capability in unmodified off-the-shelf imaging devices, including kHz-rate high-speed cameras and intensifiers. Imaging performance is found to be comparable to embedded-MLA designs, and results from the PPIV measurement of 4D flows around a ctenophore Mnemiopsis ('comb jelly') using the high-speed system is hereby presented.
- 3D particle image velocimetry
- ctenophore Mnemiopsis
- modular plenoptic