Multistage imaging process in digital SAR imaging

Synthetic aperture radar (SAR) is a type of imaging radar which has high spatial resolution, but the digital imaging processing of SAR data requires a large amount of computation, making real-time imaging difficult. Owing to the fact that different kinds of terrain structure and artificial target require different spatial resolutions, the idea of imaging in multistages to reduce the computation requirement arises. The fundamental theory of the multistage imaging process is described. The problems peculiar to this process are discussed, such as the autoadaption of spatial resolution, and the mosaic of images formed from different stages of the imaging process. The computation requirement of the multistage imaging process is also roughly estimated in the paper, and an experimental software system and results are described.