1. An apparatus for detecting concealed weapons disposed on a subject's body, the apparatus comprising: a millimeter wave camera having a field of view and operative to detect millimeter wave radiation within said field of view and further operative to provide a sequence of images from a plurality of different angles about the periphery of the subject's body; a image processing system, coupled to the millimeter wave camera, comprising: a spatial median filter for performing spatial median filtering on said sequence of images to provide filtered images, a 2-class segmentation filter for classifying each pixel in the sequence of images into one of two classes of pixels, a plurality of median filters operative to receive one of a plurality of row evolution images and provide a median filtered row evolution image output, plurality of valley identification modules operative to locate and identify valley edges in a corresponding one of said plurality of row evolution images, plurality of valley identification modules operative to locate and identify ridges in a corresponding one of said plurality of row evolution images, wherein said image processing system is operative to: transform said sequence of images of the periphery of the body into a plurality of spatio temporal images formed by assembling together, for each specific row number, all those image rows with the specific row number in successive millimeter wave images in the original sequence, said plurality of spatio temporal images corresponding to a plurality of row evolution images, classify each of said plurality of row evolution image according to its location within the body's image, calculate the strength of said identified valley edges and ridges; identify an object of a class of preselected objects as a function of the identified and calculated strength of valley edges and the identified and calculated strength of ridges in each of said plurality of row evolution image; and to provide an output indicative of an identified object.