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University of Massachusetts Boston

Physics Faculty Publications

Fourier transform optics

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Full-Text Articles in Physics

Medical Image Processing Using Transient Fourier Holography In Bacteriorhodopsin Films, Sri-Rajasekhar Kothapalli, Pengfei Wu, Chandra S. Yelleswarapu, D.V.G.L.N. Rao Dec 2004

Medical Image Processing Using Transient Fourier Holography In Bacteriorhodopsin Films, Sri-Rajasekhar Kothapalli, Pengfei Wu, Chandra S. Yelleswarapu, D.V.G.L.N. Rao

Physics Faculty Publications

Real time image processing is demonstrated by recording and reconstructing the transient photoisomerizative grating formed in the bR film using Fourier holography. Desired spatial frequencies including both high and low band in the object beam are reconstructed by controlling the reference beam intensity. The results are in agreement with a theoretical model based on photoisomerization grating. We exploit this technique to process mammograms in real-time for identification of microcalcifications buried in the soft tissue for early detection of breast cancer. A feature of the technique is the ability to transient display of selected spatial frequencies in the reconstructing process which …


Optical Implementation Of The Wavelet Transform By Using A Bacteriorhodopsin Film As An Optically Addressed Spatial Light Modulator, Joby Joseph, F. J. Aranda, D.V.G.L.N. Rao, B. S. Decristofano, B. R. Kimball, M. Nakashima Sep 1998

Optical Implementation Of The Wavelet Transform By Using A Bacteriorhodopsin Film As An Optically Addressed Spatial Light Modulator, Joby Joseph, F. J. Aranda, D.V.G.L.N. Rao, B. S. Decristofano, B. R. Kimball, M. Nakashima

Physics Faculty Publications

An optical system utilizing the photoinduced dichroism in a bacteriorhodopsin film has been demonstrated for the optical implementation of wavelet transforms. The dichroism, induced by the image of a wavelet filter on a bacteriorhodopsin film leads to polarization rotation of the Fourier components of an image. The polarization-rotated Fourier components of an input scene are analyzed with a polarizer to give the wavelet transform components. The dichroism is induced with beams whose profiles are determined by wavelet filters in order to perform the optical wavelet transform.