Cross-correlation image tracking for drift correction and adsorbate analysis

A digital image tracking algorithm based on Fourier-transform cross-correlation has been developed to correct for instrumental drift in scanning tunneling microscope images. A technique was developed to eliminate cumulative tracking errors associated with fractional pixel drift. This tracking algorithm was used to monitor conductance changes associated with different conformations in conjugated molecular switch molecules and to trace the diffusion of individual benzene molecules on Ag{110}. Molecular motions have been tracked for up to 25 h (400 images) of acquisition time.