Accession Number : ADP006739

Title :   Multiplicative to Additive Speckle Noise Conversion via Phase Cancellation with Photorefractive Phase Conjugators,

Corporate Author : TUFTS UNIV MEDFORD MA ELECTRO-OPTICS TECHNOLOGY CENTER

Personal Author(s) : Khoury, J. A. ; Biernacki, A. M. ; Woods, Charles L. ; Cronin-Glolmb, M.

Report Date : 22 MAY 1992

Pagination or Media Count : 2

Abstract : A new technique for dealing with multiplicative complex speckle noise on coherently imaged amplitude objects is presented. This technique uses phase cancellation via quadratic nonlinearity to convert the multiplicative noise into additive noise on the Fourier spectrum. This is accomplished using a noisy image as the pump and a clean planar reference beam as the probe in a degenerate four-wave mixing phase conjugator. The counterpropagating pump is provided by the phase conjugate of the noisy image from a total internal reflection self-pumped phase conjugator whose input is the noisy image transmitted through the first crystal. The phase conjugate output is read off from the clean probe; the remaining noise on the Fourier spectrum of the output image is additive and can be removed nonlinear filtering in the Fourier lane.

Descriptors :   *COHERENT OPTICAL RADIATION, *OPTICAL IMAGES, ADDITIVES, AMPLITUDE, CANCELLATION, CRYSTALS, FILTRATION, IMAGES, INPUT, INTERNAL, INTERNAL REFLECTION, MIXING, NOISE, OUTPUT, PHASE, PROBES, PUMPS, REFLECTION, NONLINEAR SYSTEMS, LASER BEAMS, BEAM SPLITTING, OPTICAL LENSES, IMAGE PROCESSING, SYMPOSIA.

Subject Categories : Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE