BACKGROUND TECHNIQUE FOR DETECTING CORRELATED COLLOIDAL MOTION MASKEDBY THERMAL NOISE AND PROJECTION EFFECTS

This article presents a novel background technique that enables one to distinguish correlated motion of colloidal particles from random ther mal effects and projection effects in video microscopy recordings that have been converted into digital lists of apparent particle trajector ies. The idea is that one can construct reference data sets lacking an y correlated motion from actual observations by randomly translating s ingle particle trajectories. One, therefore, detects genuine correlati ons with a statistical measure by comparing the results for the origin al and background data sets. The success of this technique is demonstr ated here by numerical simulations. (C) 1996 American Institute of Phy sics.