Characterization of the diffusive dynamics of particles with time-dependent asymmetric microscopy intensity profiles

摘要: We put forth an algorithm to track isolated micron-size solid and liquid particles that produce time-dependent asymmetric intensity patterns. This method quantifies the displacement of a particle in image plane from peak spatial cross-correlation function with reference image. The sharpness results subpixel resolution. demonstrate utility for tracking droplets changing shapes producing images exaggerated asymmetry. compare accuracy diffusivity determination known size by this common techniques our is superior. address several open questions on characterization diffusive behaviors. show particles, diffusing root-mean-square 0.6 pixel widths time between two successive recorded frames, more accurate determinations result mean squared (MSD) lag times up 5 intervals MSDs determined non-overlapping displacements do not yield diffusivities. discuss optimal length sequences lower frame rates affect estimated diffusivity.