Optimization of the antenna distribution of a microwave-based body scanner profiting from an automatic quality assessment of the microwave images

The problem how to enhance the security in public places is in the focus of attention nowadays. Methods for detection of concealed hazards are attributed to remote sensing issues. In the present work microwave tomography principles are employed. Operations are performed on Synthetic Aperture Radar (SAR) with frequencies from 75 GHz to 100 GHz (Wband). This span corresponds to wavelengths of 3 to 4 mm which allows to resolve reflectors up to millimeter size. Processing of the measurement data results in an image containing visual information about the inspected object. The quality of the acquired image depends on the amount of visual degradations encountered during processing of SAR data. There are a few sources of artifacts. We are focusing on distortions caused by lack of signals to process. The amplitude of these artifacts increases dramatically with reducing of the antennas number in the system. The peaks may be comparable to amplitudes of real reflectors. Besides antennas number, antennas positions have an influence on quality of the image. A combination of the number of antennas, their spatial distribution and distance between the neighbors is called the configuration of the measurement system. Finding the trade-off between the system configuration and quality of imaging is a challenge faced by any developing system. Some procedure for determining of the optimal configuration has to be applied. However, quality of images acquired from the found configuration cannot be adequately estimated by the human eye (e.g. see Fig. 3). In this work an automatic method for estimation of quality of microwave imaging is suggested.