Ls. Hibbard et al., COMPUTED 3-DIMENSIONAL RECONSTRUCTION OF MEDIAN-EMINENCE CAPILLARY MODULES - IMAGE ALIGNMENT AND CORRELATION, Journal of Microscopy, 171, 1993, pp. 39-56
Image alignment is an absolute requirement for three-dimensional (3-D)
reconstruction from serial sections, and Fourier correlation is the m
ost powerful way to compute alignments. The rotational and translation
al components of misalignment can be corrected by an iterative correla
tion procedure, but for images having significant differences, alignme
nt can fail with a likelihood proportional to the extent of the differ
ences. We found that translational correction was determined much more
reliably when low-pass filters were applied to the product transforms
from which the correlations were calculated. Rotational corrections b
ased on polar analyses of the auto-correlations of the images instead
of on the images directly contributed to more accurate alignments. The
se methods were used to generate 3-D reconstructions of brain capillar
y modules from serial-section mosaics of digitized transmission electr
on micrographs.