The proposed system would offer the widespread use of practical fiber-sensing applications. It is found that, by applying these two components to the calibration-based phase-shifting projected fringe profilometry, absolute 3-D surface profile measurement accuracy on the order of microns can be achieved. Computer simulation confirms the discrimination sensitivity improvement of the spectrogram through apodized window functions. The linear tricolor sampling pattern is described in detail as well as a method for computer generating the tricolor grating. Steady-state Bragg diffraction nondegenerate four-wave mixing in a Ce:Fe:LiNbO3 photorefractive crystal as a function of the crystal temperature is described. Then an analytical expression that relates phase-error distributions to optical system parameters is derived as a direct extension of the simulation results. Optical pattern recognition with microlasers Eung-Gi Paek; 13.
Recent work on dynamic fiber holographic processes is discussed. Holography and Spatial Filtering; 10. The volume begins with the standard photoreactive models, optical properties, wave mixing, hologram formation memories, three-dimensional data storage dynamic, interconnections, space-time processing, and application of photoreflective material to wavefront connection and to femtosecond lasers. Strictly speaking, all the physical sources are neither strictly coherent nor strictly incoherent. Zhao, Spectral and Spatial Diffraction in a Nonlinear Photorefractive Hologram. Interferometric techniques have been employed by a number of investigators to determine the phase modulating characteristics of popular spatial light modulators.
Yu is a pioneer in optical information processing, and a famous professor who is widely respected for his great contribution in optical technology and education. Finally, the electro-optic effect can be used to change the refractive index of the crystal fiber, which in turn changes the wavelength response of the stored volume grating. Using current integrated optics and electronic technology this optical neural system attains high learning and operational speed. In this paper, we present a hybrid optical neural network using a high resolution video monitor as a programmable associative memory. Microwave Opt Technol Lett 15: 16—20, 1997. Applications of photrefractive devices in optical pattern recognition Ziangyang Yang; 12.
An N × N interconnection network can be realized by N holograms, for which the network can be reconfigured in real-time mode. To exploit the spatial information contents for sensing, a multimode fiber specklegram sensor with a hetero-core fiber structure is used. Yeh, Cross-talk in Photorefractive Hologram Memory. Angular and wavelength selectives are calculated which show that wavelength-multiplexed reflection fiber hologram offers higher and uniform selectivity. A selection of basic geometric shapes may be chosen to correspond to particular classes of objects.
C 1996 Society of Photo-Optical Instrumentation Engineers. This text for senior undergraduate and first-year graduate students as well as practitioners summarizes and reviews some of the recent advances in optical information processing and communications. Thanks to the book's interdisciplinary character, seasoned researchers and practitioners will also find new insights and new ideas, as well as a global overview of this interesting and dynamic optics subfield. A one-step method for recording color information on a monochrome transparency using a linear tricolor sampling pattern is proposed. Optical implementation of mathematical morphology Tien-Hsin Chao; 6. Sixteen chapters present the fundamental aspects and the recent advances of photorefractive optics, particularly potential applications in the area of informational infrastructures. A disadvantage of Kohonen - networks can be the comparatively long training time needed , especially if large data sets are used since every data vector must be presented several times to the network for weight adaptation.
An extension of this idea is now presented. Fabrication of single-crystal fibers using a laser-heated pedestal growth system is given. Applications of photrefractive devices in optical pattern recognition Ziangyang Yang; 12. The experimental r esults confirm that this unique sensor indeed can be used to sense the concentration of targeted chemical agent via the change in refractive index. The anomalies of photovoltaic current in Ce:Fe doped LiNbO3 crystal at 55 and 75 degree s C temperatures have been investigated. All of these windows can be synthesized in a photorefractive crystal by angular multiplexing holographic technique, which renders the system more adaptive.
For demonstration, dynamic displacement sensing is illustrated in which we have observed that the rate change and the trend of the fiber perturbation can indeed be detected. Using the Kukhtarev's charge transport model, the spectral response and electrical tuning of the photorefractive filter were analyzed. As long as the wavelength difference between the writing and reading beams is sufficiently large, there is only a small amount of increase in coupling. This is going past optical communications in that it contains similar issues similar to sensing, screens, computing, and knowledge storage. Nonlinear optical correlators with improved discrimination capability for object location and recognition Leonid P. An efficient and secure algorithm for random phase mask generation used in optical data encryption and transmission system is proposed, based on Diffie-Hellman public key distribution.
First, the dependence of phase-error distribution and measurement uncertainty on speckle size and grating pitch is numerically studied, based on the Karhunen—Loève expansion method. He is a recipient of the 1983 Faculty Scholar Medal for Outstanding Achievement in Physical Sciences and Engineering, a recipient of the 1984 Outstanding Researcher in the College of Engineering, was named Evan Pugh Professor of Electrical Engineering in 1985 at Penn State, a recipient of the 1993 Premier Research Award from the Penn State Engineering Society, and was named Honorary Professor in Nanki University in 1995. As such, position-invariant diierentiation and localization is achieved with an approach quite diierent than those employed in invariant pattern recognition and localization in conventional images. The advances of photorefractive optics have demonstrated many useful and practical applications, which include the development of photorefractive optic devices for computer communication needs. Composite filter synthesis as applied to pattern recognition Shizhou Yin and Guowen Lu; 9.
This technique essentially uses the normalized correlation peak intensity values as the iterative feedback into the input and Fourier planes to update the weight coefficients for the reference patterns and the composite intensity compensation filter. However, as wavelength difference between them is adequately small but larger than the minimum wavelength separation calculated by Kogelnik's formula , the coupling between two channels increases to a significant value and then decreases. After that a brief theory is reviewed. When a laser beam is launched into a multimode fiber, the exit light field produces a complicated speckle pattern caused by the modal interference of the fiber. By searching the redundant interconnection links, a method that removes all negative links is introduced. We note that the dynamic sensing technique can be applied to a variety of sensing parameters, e. Representations of fully complex functions on real-time spatial light modulators Robert W.