SQUARE ANTI-SYMMETRIC UNIFORMLY REDUNDANT ARRAY CODED APERTURE IMAGING SYSTEM

A square anti-symmetric uniformly redundant array coded aperture includes transparent and opaque cells and exhibits a normal mask pattern at a first position and a complementary mask pattern when rotated to a second position rotationally offset by 90.degree. from the first position. The coded aperture is used in a system for imaging a source of non - focusable radiation such as gamma rays or x-rays. The imaging system includes the coded aperture (22) for receiving the radiation (20) emitted by the source and generating coded shadows therefrom at the two positions, a rotating platform (24) and motor (30) for rotating the coded aperture between the two positions, a position sensitive detector (10) generating coded optical signals of the shadows sequentially impinging thereon, an optical signal converter (34) generating coded electrical signals of the optical signals, and a signal processor (14) decoding the electrical signals and generating an image signal of the source of non-focusable radiation.