1. An imaging arrangement for a coded aperture imaging system comprising: a source of nonfocusable radiation; a position sensitive detector; mosaic array aperture means formed from a basic r by s array and neighboring cyclic versions of said basic r by s array adjacent to said basic r by s array, said mosaic array aperture means substantially aligned with said source of nonfocusable radiation and said position sensitive detector to form an encoded aperture image; said encoded aperture image formed by a circular correlation of said mosaic aperture array and said source of nonfocusable radiation such that all object source points of said source of nonfocusable radiation contribute a complete cyclic version of said basic r by s array within a minimal detector area for sources aligned off axis; means for reconstructing an image of said source from said encoded aperture image.