Passive millimetre wave imaging and seenrity

Passive millimetre wave imaging is currently being considered as a technology that can contribute to security in several scenarios such as anation, high value buildings etc. The unique property of imaging in this waveband is that clothes are relatively transparent and therefore hidden weapons and contraband can be detected. The ability of these systems to meet specific requirements is dependent on several key parameters that have to he optimised during the design process and include the spatial resolution, thermal sensitivity, field of new and frame rate. The optical properties of skin, weapons and clothing give rise to target contrast. The impact on system performance of target contrast and the key system parameters is discussed. A prototype 35GHz imaging system that has been operated both indoors and outdoors is described to illustrate the current status of this technology.