Limited angle reconstruction using stabilized algorithms

Summary form only given, as follows. The tomographic reconstruction of multidimensional waveforms from limited data is considered. The particular case treated is when there is access to projections over only a limited view of an object. The algorithm that has been developed can be considered to be an enhanced version of the projection onto convex sets (POCS) technique. Two problems with the original algorithm, dependence of the final answer upon the starting guess and the question of when to terminate the procedure, are addressed. An enhanced version computes an ensemble of inverses that are consistent with both the observed data and the a priori knowledge by executing the POCS algorithm a multiplicity of times with measured data plus random noise as a starting guess. The resulting ensemble of inverses is analyzed in order to create an a posteriori filter. This filter is applied to the restored image, the result of executing the POCS algorithm on the measured data. The resulting image exhibits less noise amplification in the final result than is the case with the original procedure. The enhanced algorithm seems to perform well in the presence of moderate noise and is less dependent on both starting data and the number of iterations