Calibration, Reconstruction, and Rendering of Cylindrical Millimeter-Wave Image Data

Cylindrical millimeter-wave imaging systems and technology have been under development at the Pacific Northwest National Laboratory (PNNL) for several years. This technology has been commercialized, and systems are currently being deployed widely across the United States and internationally. These systems are effective at screening for concealed items of all types; however, new sensor designs, image reconstruction techniques, and image rendering algorithms could potentially improve performance. At PNNL, a number of specific techniques have been developed recently to improve cylindrical imaging methods including wideband techniques, combining data from full 360-degree scans, polarimetric imaging techniques, calibration methods, and 3-D data visualization techniques. Many of these techniques exploit the three-dimensionality of the cylindrical imaging technique by optimizing the depth resolution of the system and using this information to enhance detection. Other techniques, such as polarimetric methods, exploit scattering physics of the millimeter-wave interaction with concealed targets on the body. In this paper, calibration, reconstruction, and three-dimensional rendering techniques will be described that optimize the depth information in these images and the display of the images to the operator.