A Simple Approach to Modifying the Contrast Basis in Contrast Source Inversion

A per-iteration processing technique is applied to the Contrast Source Inversion algorithm to project a standard element-based contrast recovery step onto an alternative set of basis functions. For the grain storage monitoring application the alternative basis is advantageously chosen based on problem geometry to improve algorithm performance in resonant enclosures. Results for both synthetic and experimental grain storage problems demonstrate that the proposed basis projections significantly improve imaging results without requiring any major changes to the CSI gradient calculations.