Aligning tilt slices for 3D TEM tomography based on 2D to 1D Radon transform

Aligning a tilt series in 3D TEM tomography is not only a shift compensation problem among tilt slices, but rather a parameter registration problem, in which a tilt axis should be registered on each slice with its position/orientation. A new method for 3D tilt alignment is suggested in this paper based on analyzing 1D signals resulting from projecting individual 2D slices in various directions (2D Radon transform). The axis orientation and position are identified by techniques of 1D shift compensation, 2D frequency analysis, etc. Without any information loss during the calculating process, the accuracy and the robustness for axis registration are ensured. Meanwhile, essentially working on 1D data provides the concrete base of computing performance. Based on this method, no any extra work of adding fiducial markers into samples, or detecting corners/edges from slice images are required; therefore both experimental and computational efforts could be heavily reduced.