3D Fast Factorized Back-Projection in Cartesian Coordinates

This paper presents a novel 3D Fast Factorized Back-Projection (FFBP) algorithm that is based on an extension of the quadtree approach. A flexible 3D tree structure is generated from a modified Morton order or Z-order curve, a recursive space-filling curve that is suitable for FFBP algorithms. This paper presents, as well, an original method for defining sub-apertures. The proposed algorithm can be applied to any flight path and is about 90 % faster than the direct back-projection, yielding high-resolution 3D images with low phase errors and high degrees of coherence. (AU)