Figure 4
Comparison of alignments by SIFT and AMST when no alignment marking were available in the platinum coating due to embedding by minimal resin technique (P. dumerilii dataset, EMPIAR-10310). (a) Cropped region from the top of the dataset after alignment by SIFT and the plot of the alignment quality along the same region. The blue and yellow plot correspond to displacement errors in the top and bottom part of the dataset, respectively, as described in Fig. 3. Three major outlier slices are visible in approximately 2 µm distance, (arrowheads and dashed lines) which correspond to auto-focus and auto-stigmation operations of the microscope. (b) Illustration of the same region as in (a) after alignment by AMST with SIFT serving as pre-alignment. The displacement error of major outlier slices was reduced from up to over 80 nm to an error less than 16 nm. Additionally, the alignment quality generally improved from an average in displacement error of around 7 nm to 2.5 nm.
