Reconstruction of 3D Vertebral Models from a Single 2D Lateral Fluoroscopic Image - Spinal Imaging and Image Analysis - page 351

Fig. 6 Schematic illustration of computing 3D point pairs between a model and the input image
from the established 2D/2D correspondences

3.3.2 3D/3D Reconstruction

As soon as a set of 3D point pairs are available, the problem of surface recon-
struction is then solved optimally in three sequential stages using the algorithm
presented in [ 28 ]: scaled rigid registration, statistical instantiation, and regularized
shape deformation. For details about how to implement these three sequential
stages, we refer to our previous work [ 28 ]. Figure 7 shows different stages of the
reconstruction process, where a scaled surface model of the L2 lumbar vertebra was
reconstructed from a single lateral fl fluoroscopic image.

Fig. 7 Different stages of the reconstruction process. Left the smoothed contours; left middle the
landmark-based initialization of the mean model (grey) of the PDM; right middle the reconstructed
model (white); right the apparent contours (yellow) extracted from the reconstructed model versus
the image contours (white)