Industrial Applications of Microwave Imaging

After a definition of the term "Imaging" in the microwave field, optical and microwave images will be compared in terms of information content, method and simplicity of access. The current and potential future industrial applications including the fields of robotics and microwave vision, biomedical applications, imaging of buried objects, nondestructive testing and vehicular guidance are assessed. The role of inverse scattering giving the theoretical background for microwave imaging will be considered. Using the specific examples of a 94 GHz three dimensional imaging radar sensor for autonomous vehicles in production plant environments, distinguished features of microwave imaging sensors are discussed. An evaluation of their benefits with respect to their ability to effectively contribute to general remote sensing tasks also in competition or in cooperation with other sensors will be carried out. System design and imaging results of a multitask 94 GHz pulse Doppler radar with 25 cm radial and 1.5° angular resolution, which has been described in greater detail elsewhere [1,2], are given under the aspects of their contribution to a multi-sensor system. While 2-D scanning can be performed close to real time with a data flow of up to 104 volume cells per second, the acquisition of three-dimensional radar images at the present state is restricted to stationary scenes. To point out specific mm-wave scattering phenomena, radar images of typically structured indoor situations are presented. The results demonstrate that for guidance of autonomous vehicles, the extraction of geometrical properties of the environment by microwaves are a promising approach.