(a) x -y Trajectory of a 100 nm diameter fluorescent bead immobilized on the coverslip and imaged during a time lapse movie. The x and y displacement is due to the sample drift. Z position is stabilized by the axial feedback mechanism. Green trace is made of the measured position of the bead as seen in the green imaging channel. Red trace corresponds to the red imaging channel. The orange dashed trace is obtained after application of the registration function to the red points. Black crosses represent the positions of the fiducial markers. (b) Histograms of the localization precision after Gaussian fitting of the bead (weighted least squares). 1.5 nm and 1.3 nm. (c) Scatter plot of the residual x and y offset x
. The blue circle has a radius of 10 nm, the red circle has a radius given by .