3D3C velocities in a single camera
MicrovechasdevelopedanewlightﬁeldvolumetricPIV(LF-PIV) system. Microvec LF-PIV can resolve 3D velocity ﬁelds through MART based reconstruction and 3D cross correlation. This new system can provide an interesting alternative and affordable substitutetoaTomographicPIV.Itisbasedononlyonecompactcamera,andcanbeusedtocalculate3D3Cvelocityinapplicationsand environments with space constraint.
In-house light ﬁeld camera was developed according to plenoptic imaging where a customised micro-lens array (MLA) is precisely positioned one focal length away from the CCD of a 29 megapixel camera (See Figure 1 and 2). The MLA consists of 458×301 hexagonal lens unit, which maximises the pixel usage when compared to square lens unit. Light ﬁeld image of tracer particle article can be simulated via linear Gaussian optics.
LF-PIV system pre-determines the location of a particle through inverse dense ray tracing (DRT) and reconstructs the voxel value using multiplicative algebraic reconstruction technique (MART).
DRT-MART technique implemented in Microvec LF-PIV achieves higher reconstruction resolution at much better computational efﬁciency than the MART method. To speed up the calculations even more, the system supports GPU and its parallel processing.