<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Michael Marxen</style></author><author><style face="normal" font="default" size="100%">Sullivan, P. E.</style></author><author><style face="normal" font="default" size="100%">Loewen, M. R.</style></author><author><style face="normal" font="default" size="100%">Bernd Jähne</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Comparison of Gaussian particle center estimators and the achievable measurement density for particle tracking velocimetry</style></title><secondary-title><style face="normal" font="default" size="100%">Exp. Fluids</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2000</style></year></dates><volume><style face="normal" font="default" size="100%">29</style></volume><pages><style face="normal" font="default" size="100%">145-153</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A series of numerical simulations were conducted to investigate the performance of two particle center estimation algorithms for Particle Tracking Velocimetry: a simple three-point Gaussian estimator and a least-square Gaussian. The smallest position error for images with reasonable noise levels was found to be approximately 0.03 pixels for both estimators using particles with diameters of 4 pixels. As both estimators performed equally well, use of the simple three-point Gaussian algorithm is recommended because it executes 100 times faster than the least-square algorithm. The maximum achievable measurement density and accuracy for the three-point Gaussian estimator were determined with a numerical simulation of an Oseen vortex. Uncertainty measures have been introduced to filter out unreliable displacement measurements. It was found that 4 to 5 velocity vectors could be obtained within a 32×32 pixel area with an average displacement error of 0.1 pixels. This doubles the spatial resolution of conventional cross-correlation based Particle Image Velocimetry at comparable accuracy.</style></abstract></record></records></xml>