Medical volume images contain ambiguous and low-contrast boundaries around
which existing fully- or semi-automatic segmentation algorithms often cause
errors. In this paper, we propose a novel system for intuitively and efficiently
refining medical volume segmentation by modifying multiple curved contours.
Starting with seg-mentation data obtained using any existing algorithm,
the user places a three-dimensional curved cross-section and contours of
the foreground region by drawing a cut stroke, and then modifies the contours
referring to the cross-section. The modified contours are used as constraints
for deforming a boundary surface that envelops the foreground region, and
the region is updated by that deformed boundary. Our surface deformation
algorithm seamlessly integrates detail-preserving and curvature-diffusing
methods to keep important detail boundary fea-tures intact while obtaining
smooth surfaces around unimportant boundary regions. Our system supports
topo-logical manipulations as well as contour shape modifications. We illustrate
the feasibility of our system by pro-viding examples of its application
to the segmentation of bones, muscles, kidneys with blood vessels, and
bowels.