Mosaic of coded aperture arrays

• US 4,228,420 A
• Filed: 09/14/1978
• Issued: 10/14/1980
• Est. Priority Date: 09/14/1978
• Status: Expired due to Term

• Current Assignee: United States Government As Represented By The Department of Energy
• Original Assignee: United States Government As Represented By The Department of Energy
• Inventors: Fenimore, Edward E., Cannon, Thomas M.
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US05/942,228
• Time in Patent Office: 761 Days
• Field of Search: 350/162 R, 350/162 SF, 350/162 ZP, 350/319, 358/5, 250/550, 250/505, 250/363, 250/237 R, 250/237 G, 250/445 T, 250/227, 250/320, 340/146.3 F, 340/146.3 P
• US Class Current: 382/324
• CPC Class Codes: G01T 1/295 using coded aperture devices, e.g. Fresnel zone plates handling of radiation of particles, e.g. using diaphragms, collimators, diffraction G21K1/00
• CPC Class Codes: G03H 1/06 using incoherent light

Abstract

The present invention pertains to a mosaic of coded aperture arrays which is capable of imaging off-axis sources with minimum detector size. Mosaics of the basic array pattern create a circular on periodic correlation of the object on a section of the picture plane. This section consists of elements of the central basic pattern as well as elements from neighboring patterns and is a cyclic version of the basic pattern. Since all object points contribute a complete cyclic version of the basic pattern, a section of the picture, which is the size of the basic aperture pattern, contains all the information necessary to image the object with no artifacts.

Claims

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.

2. The imaging arrangement of claim 1 wherein said mosaic array aperture consists of a basic r by s uniformly redundant array and neighboring arrays to form a 2r by 2s aperture.

3. The aperture of claim 1 wherein said basic r by s array comprises a uniformly redundant array.

4. The aperture of claim 1 wherein said basic r by s array comprises a random array.