Digital simulation and processing applied to coherent imaging systems

A synthetic-aperture system, such as a coherent sidelooking radar, records a quasi-hologram of the scene which is illuminated by the transmitted radiation. Conventionally, the recorded pattern is converted to an image using optical processing. However, optical processing does not always provide the flexibility, dynamic range, or accuracy necessary to produce optimum images. Digital processing offers the potential for more generalized processing operations which provide large dynamic range and can correct for system aberrations and other image degrading effects. This paper presents a general method of digital processing which has been developed for synthetic aperture systems. Results are given for processing of radar, sonar, and millimeterwave recordings.