Velocity errors in particle tracking velocimetry (PTV) are studied. Whenusing high-speed video cameras, the velocity error may increase at a highcamera frame rate. This increase in velocity error is due to particle-positionuncertainty, which is one of two sources of velocity errors studied here. Theother source of error is particle acceleration, which has the opposite trend ofdiminishing at higher frame rates. Both kinds of errors can propagate intoquantities calculated from velocity, such as the kinetic temperature ofparticles or correlation functions. As demonstrated in a dusty plasmaexperiment, the kinetic temperature of particles has no unique value whenmeasured using PTV, but depends on the sampling time interval or frame rate. Itis also shown that an artifact appears in an autocorrelation function computedfrom particle positions and velocities, and it becomes more severe when a smallsampling-time interval is used. Schemes to reduce these errors aredemonstrated.
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