Improving BP efficiency by the manner of offline projection

For the cases where the imaging geometry are known and deterministic, a novel method of actualizing the time domain back projection (BP) imaging called offline projection is proposed to accelerate the imaging procedure. Firstly, the basic idea of offline projection is presented. Then, a quantitative spatial sampling criterion for range profiles in offline projection is given. Finally, Simulation and experimental results show that the proposed method can evidently reduce the imaging time costs as well as maintaining the focusing quality.