Interpolation by directed distance morphing

摘要

Shape-based interpolation (SBI) is used for interpolation between binary serial slice images. Although SBI approximates the interslice geometry more accurately than traditional techniques such as linear (L) or cubic spline (CS) interpolation, SBI produces only a binary result. This paper extends SBI to interpolation of grayscale images (SBIG) using simulated 3D distance maps to produce a grayscale image volume. Results of SBIG are superior visually (sharper detail, no artificial intensities) and quantitatively to L or CS. This is particularly evident in sagittal and coronal reconstructions. Clipping artifacts due to nonoverlapping structures or rapid changes in image brightness are minimized using simulated 3D maps. However, when objects between slices do not overlap, shape-based interpolation results in compressed or nonexistent geometry in some or all of the interpolated slices. The nonoverlapping problem is described and quantified. A new interpolation algorithm, directed distance morphing, is introduced and used to address the nonoverlapping problem.