Optical ranked-order filtering using threshold decomposition

Patent · Tue Aug 14 04:00:00 EDT 1990

OSTI ID:6377465

Allebach, J P; Ochoa, E; Sweeney, D W

This patent describes a hybrid optical/electronic system. It performs median filtering and related ranked-order operations using threshold decomposition to encode the image. Threshold decomposition transforms the nonlinear neighborhood ranking operation into a linear space-invariant filtering step followed by a point-to-point threshold comparison step. Spatial multiplexing allows parallel processing of all the threshold components as well as recombination by a second linear, space-invariant filtering step. An incoherent optical correlation system performs the linear filtering, using a magneto-optic spatial light modulator as the input device and a computer-generated hologram in the filter plane. Thresholding is done electronically. By adjusting the value of the threshold, the same architecture is used to perform median, minimum, and maximum filtering of images. A totally optical system is also disclosed.

• Assignee: Dept. of Energy, Washington, DC (USA)
• Patent Number(s): US 4949389; A
• Application Number: PPN: US s 7-106295
• OSTI ID: 6377465
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426000 -- Engineering-- Components
Electron Devices & Circuits-- (1990-)
440600* -- Optical Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
COMPUTERS
ELECTRONIC CIRCUITS
FILTERS
HOLOGRAPHY
IMAGE PROCESSING
MAGNETO-OPTICAL EFFECTS
NONLINEAR PROBLEMS
OPTICAL COMPUTERS
OPTICAL FILTERS
OPTICAL SYSTEMS
PARALLEL PROCESSING
PROCESSING
PROGRAMMING