Optimal scan for time-varying tomography. II. Efficient design and experimental validation

For pt.I see ibid., vol.4, no.5, p.642-53 (1995). In pt.I the authors presented a theoretical analysis of tomographic reconstruction of objects with spatially localized temporal variation, such as a thorax cross section with a beating heart. That analysis showed that by using an optimally scrambled angular sampling order, the scan rate required to avoid motion artifacts in the reconstructed images can be lowered as much as four times while preserving image quality. Here, the authors present a simple design procedure for the optimum choice of angular sampling pattern, which depends only on pre-specified geometric and spectral parameters and the desired spatial resolution. The resulting patterns have a simple congruential structure. Reconstruction is accomplished by interpolation to standard time-invariant scan format, followed by conventional reconstruction. The interpolation only requires linear shift-invariant separable filtering, at a negligible computational cost. Simulation results demonstrate the technique and validate the analysis for both bandlimited and approximately bandlimited objects.