Security and surveillance systems are one of the most challenging applications for infrared (IR) and terahertz (THz) imagers. The main aim of imagers is to deliver high quality images of targets of interest. One of the major challenges in this field is ability to automatically reveal objects placed on the surface of human body and covered with clothing. Terahertz imagers, which seem to be the best solution, very often provide images with low signal-to-noise ratio, low spatial resolution, and offer limited distance of imaging. A reasonable alternative seems to be an infrared camera.