A novel active millimeter-wave (MMW)quasi-aptical imaging technique, which can be effectively used for detection of concealed objects. is presented. The operation principle is based on multi-parameter active illumination of the objects with multiply decomposed and encoded radiation, separate acquisition of quasi-aptical partial images, and following digital synthesis of resultant images exhibiting enhanced quality and information content. The technique utilizes capabilities of artificial MMW sources and switching components to sweep and modulate MMW radiation within wide ranges of radiation physical parameters.Experimental and numerical simulation results are presented.