LaVision‘s FlowMaster Micro-PIV/PTV (µPIV/PTV) product range for velocimetry in microscopic dimensions evolved over nearly two decades and covers all needs of high-magnification flow diagnostics.
All hard- and software components are optimized for the specific requirements of microflow measurements which are different from applications in larger scales in many aspects.
A typical Micro-PIV/PTV system consists of a sensitive scientific camera, a pulsed laser with appropriate beam coupling and guiding, an epifluorescence microscope (single channel or stereo) and our DaVis software for image acquisition, advanced analysis and intuitive visualization (with reporting and export functionality).
Making use of fluorescent seed particles is a consequence of the situation that no light sheet can be formed in such small scales and so the background and reflections from a volume illumination needs to be blocked. An epifluorescent filter cube assures that no laser light enters the viewing/imaging beampath. The measurement plane is defined by the narrow depth of focus of the microscope's objective which also has to allow for a comparably long working distance.
Reconstructed 3D trajectories of flow tracers in a micro channel
The accuracy of the Flowmaster µPIV and µPTV results in 2D and 3D are based on proven approaches from 'standard' PIV which are enhanced by some additional algorithms specific for the challenges in Micro-PIV/PTV. Image pre-processing with signal-to-noise enhancement, image dewarping for correction of optical artifacts (by "self-calibration") and "sum-of-correlation" are steps that allow to get highest quality results even from weak signals in scarcely seeded flows.