Non-linear registration of scanning probe microscopy images

Non-linear distortions caused by thermal drift and hysteresis of piezo-scanners hinder the alignment of a series of two-dimensional scanning probe microscopy (SPM) images for Nanotomography volume images and for movies. We report on a registration method to correct these distortions. To speed up the registration of a complete stack of hundreds of two-dimensional images, the data were registered in a whole block, and a multi-resolution approach was used. Other specific problems of SPM measurements, such as image artefacts and the handling of image boundaries, were solved by introducing a mask with implicit mapping. With this approach we are able to obtain high-resolution Nanotomography images of modern nanostructured materials over large areas (1 µm) with a resolution of 10 nm. Examples are individual crystalline lamellae in a semicrystalline polymer film as well as a 50 nm wide channel in a nickel-based superalloy.