Regensburg 2007 – scientific programme

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BP: Fachverband Biologische Physik

BP 16: Poster Session I

BP 16.9: Poster

Tuesday, March 27, 2007, 17:00–19:30, Poster D

Accuracy check of detection algorithms for fluorescent colloidal spheres by simulation — •Markus Gyger — Institute for Soft Matter Physics, University of Leipzig, Linnéstr. 5, 04103 Leipzig, Germany

In the discussion about like-charge attraction of colloidal spheres confined between parallel glass-plates there have been indications that the observed attraction is an artifact due to diffraction effects in optical video microscopy. We present a simulation technique which checks the accuracy of the detection algorithms for confined fluorescent colloidal particles and allows for determination of the difference between real and detected particle position in dependance on the interparticle separation. To that aim, images of interacting particles, whose positions were detected by different particle detection algorithms, were computer generated, simulating the image-taking process of digital video microscopy. Re-detecting the particle positions from the simulated images and comparing them with the originally detected positions provides some insight into the detection accuracy and systematic errors of the detection algorithms.