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December 2010

Volume 49, Issue 12, Articles (12xxxx)

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Impact Factor and Optical Engineering

Ronald G. Driggers

Opt. Eng. 49, 120101 (Dec 30, 2010); http://dx.doi.org/10.1117/1.3524188

Online Publication Date: Dec 30, 2010

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Image-based fusion for video enhancement of night-time surveillance

Yunbo Rao, Weiyao Lin, and Leiting Chen

Opt. Eng. 49, 120501 (Dec 29, 2010); http://dx.doi.org/10.1117/1.3520553 | Cited 1 time

Online Publication Date: Dec 29, 2010

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In this paper, a novel image-based fusion video enhancement algorithm is proposed for night-time video surveillance applications by a combination of illumination fusion and based on moving objects fusion. The proposed algorithm fuses video frames from high quality day-time and night-time background with low quality night-time videos. For improving the perception quality of the moving objects, based on moving objects of region fusion method is proposed. Experimental results show the effectiveness of the proposed algorithm.
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Adaptive deblocking filter for intrablocks

Jungyoup Yang, Kwanghyun Won, and Byeungwoo Jeon

Opt. Eng. 49, 120502 (Dec 28, 2010); http://dx.doi.org/10.1117/1.3523479 | Cited 1 time

Online Publication Date: Dec 28, 2010

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The H.264/AVC deblocking filter pays little attention to intracoded blocks. We enhance this filter by extending it to use intraprediction mode information in its adaptive application to the intracoded block. Experiments show its higher coding efficiency, with blocking artifacts sufficiently minimized in intracoded blocks.
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Surface plasmon resonance due to the interface of a metal and a chiral sculptured thin film

Tariq H. Gilani, Natalia Dushkina, William L. Freeman, Muhammad Z. Numan, Devki N. Talwar, and Drew Patrick Pulsifer

Opt. Eng. 49, 120503 (Dec 23, 2010); http://dx.doi.org/10.1117/1.3525282

Online Publication Date: Dec 23, 2010

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Multiple surface plasmon resonances are experimentally observed for p-polarized as well as s-polarized incident light at the planar interface of a metal and a chiral sculptured thin film. These experimental results confirm that four surface plasmon resonances can be supported at the interface of metal-chiral sculptured thin film. Multiple surface plasmon resonances may allow for multiple simultaneous measurements by devices that utilize surface plasmon resonance for detection.
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High-efficiency light-emitting diode collimator

Daniel Vázquez-Moliní, Mario González-Montes, Antonio Álvarez, and Eusebio Bernabéu

Opt. Eng. 49, 123001 (Dec 17, 2010); http://dx.doi.org/10.1117/1.3522644

Online Publication Date: Dec 17, 2010

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We describe an analytical and numerical method to design and optimize LED (light-emitting diode) collimators. The optimization process is confirmed by optical simulations and experimental measurements of a scaled prototype. The collimator's definitive geometry and design parameters rely on the LED's emitting characteristics and the employed collimator material. The resulting parabolic-elliptical-based collimator shows an optimum performance and a compact structure with requirement for mirrored surfaces.
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Three-dimensional neuronal brain activity estimation using shrinking smooth weighted-minimum-norm focal underdetermined-system solver methods

Wassim Zouch, Mohamed Ben Slima, Imed Feki, Philippe Derambure, Abdelmalik Taleb-Ahmed, and Ahmed Ben Hamida

Opt. Eng. 49, 123201 (Dec 15, 2010); http://dx.doi.org/10.1117/1.3505847

Online Publication Date: Dec 15, 2010

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A new nonparametric method, based on the smooth weighted-minimum-norm (WMN) focal underdetermined-system solver (FOCUSS), for electrical cerebral activity localization using electroencephalography measurements is proposed. This method iteratively adjusts the spatial sources by reducing the size of the lead-field and the weighting matrix. Thus, an enhancement of source localization is obtained, as well as a reduction of the computational complexity. The performance of the proposed method, in terms of localization errors, robustness, and computation time, is compared with the WMN-FOCUSS and nonshrinking smooth WMN-FOCUSS methods as well as with standard generalized inverse methods (unweighted minimum norm, WMN, and FOCUSS). Simulation results for single-source localization confirm the effectiveness and robustness of the proposed method with respect to the reconstruction accuracy of a simulated single dipole.
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Measurement of aberrations of a solid elastic lens using a point-diffraction interferometer

Agustin Santiago-Alvarado, Sergio Vázquez-Montiel, MEMBER SPIE, Fermín-Salomón Granados-Agustín, MEMBER SPIE, Jorge González-García, Esteban Rueda-Soriano, MEMBER SPIE, and Manuel Campos-García

Opt. Eng. 49, 123401 (Dec 10, 2010); http://dx.doi.org/10.1117/1.3522645

Online Publication Date: Dec 10, 2010

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There has been a considerable recent increase in the use of variable focal length lenses (VFLLs), especially as microlenses in photographic objectives, endoscopes, microscope objectives, etc. One distinguishing feature of these VFLLs is the presence of a mechanism whereby the shape of the lens and its geometrical parameters can be changed. A new type of variable focal length lens is introduced made from elastic material. It is placed inside a mechanical mount where radial forces can be applied to its perimeter. We also present the optomechanical design and the measurement of wavefront aberrations to the third and fifth order of a solid elastic lens (SEL). A point-diffraction interferometer is used as a wavefront sensor to test changes of the lens. Geometrical changes in the lens produce changes in the aberrations. Finally, the aberrations found in the SEL (without any application of stress) are compared with aberrations obtained by means of numerical ray trace. Some experimental results are also shown.
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Multiresolution three-dimensional measurement system with multiple cameras and light sectioning method

Weiguang Zhang, Hong Zhao, and Xiang Zhou

Opt. Eng. 49, 123601 (Dec 07, 2010); http://dx.doi.org/10.1117/1.3516729 | Cited 1 time

Online Publication Date: Dec 07, 2010

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A multiresolution 3-D measurement system using multiple cameras and a light sectioning method is developed to measure complex-profile objects for which other optical measuring methods are less suited. The system is composed of four cameras, which can select different system parameters to measure the whole profile and some details of an object at the same time. Thus, the system has a multiresolution measuring feature. We mainly focus on the imaging system model, system calibration, and the data merging method, and furthermore propose a calibration method with a self-designed planar calibration target and a data merging algorithm based on empirical mode decomposition. Experimental results show that position uncertainty of a measured point within the section plane is less than 0.06 mm in a 80×80-mm2 measurement range. The system is employed to measure a blade and a gear with relatively satisfactory results.

Model and error analysis for coded structured light measurement system

Xiaojun Jia, Zhijiang Zhang, Fang Cao, and Dan Zeng

Opt. Eng. 49, 123603 (Dec 28, 2010); http://dx.doi.org/10.1117/1.3520056

Online Publication Date: Dec 28, 2010

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Coded structured light can rapidly acquire the shape of unknown surfaces by projecting suitable patterns onto a measuring surface and grabbing distorted patterns with a camera. By analyzing the deformation patterns appearing in the images, depth information of the surface can be calculated. This paper presents a new concise and efficient mathematical model for coded structured light measurement system to obtain depth information. The interrelations among model parameters and errors of depth information are investigated. Based on the system geometric structure, the results of system parameters affecting object imaging can be obtained. Also, the dynamic deformation patterns can be captured under different measurement conditions. By analyzing the system parameters and depth information errors, the system constraint conditions can be determined, and the system model simulation and error analysis are discussed in experiments, too. Also, the system model based on optimal parameters is utilized to implement reconstruction for two objects.

Deformation measurement method for spatial complex tubular joints based on photogrammetry

Bao-Quan Shi, Jin Liang, Zhen-Zhong Xiao, Xiao-Qiang Zhang, and Qing Liu

Opt. Eng. 49, 123604 (Dec 28, 2010); http://dx.doi.org/10.1117/1.3520059

Online Publication Date: Dec 28, 2010

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The destruction of spatial complex tubular joints may lead to failure of the whole tubular structure, thus it is necessary to analyze the mechanical properties of spatial complex tubular joint. In this paper, a novel method based on close range photogrammetry to accurately measure the three-dimensional (3D) deformation of spatial complex tubular joints during loading test is proposed. Artificial targets are pasted on the deformation area before loading. The 3D coordinates of these targets are reconstructed by analyzing the images captured at each stage, and the coordinate systems of different stages are registered together by means of global transformation points. The whole field 3D deformation under different load levels is then obtained by tracking the homonymous targets among different stages. It is helpful for further analysis of the mechanical properties. Two different precision evaluation experiments indicate that the proposed method could achieve accuracy of 0.1mm/m. Two full scale tubular joints are tested and a feasible solution for improving the load carrying capacity of the tested tubular joints is thus obtained as per the measured results. For comparison, finite element analysis is employed to predict the deformation in a traditional way. The deformation tendency measured by two methods agrees well.

Simplified photonic microwave frequency measurement using a loop mirror filter

Jian Dai, MEMBER SPIE, Kun Xu, Xiaoqiang Sun, MEMBER SPIE, Yan Li, Jian Wu, and Jintong Lin

Opt. Eng. 49, 123605 (Dec 23, 2010); http://dx.doi.org/10.1117/1.3524237 | Cited 1 time

Online Publication Date: Dec 23, 2010

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A more simplified photonic microwave frequency measurement configuration based on a loop mirror filter is proposed and experimentally demonstrated. It is implemented by propagating a carrier-suppressed double-sideband modulated optical signal through a loop mirror filter. The ratio between the optical powers of the two output ports provides a direct measurement of the unknown signal frequency. This scheme can solve the main problems that exist in previous work. A proof-of-concept experiment is performed with a measurement range of 6 to 18 GHz and resolution less than 0.35 GHz.

Optical probe for porosity defect detection on inner diameter surfaces of machined bores

Ojas P. Kulkarni, Mohammed N. Islam, and Fred L. Terry, Jr.

Opt. Eng. 49, 123606 (Dec 21, 2010); http://dx.doi.org/10.1117/1.3526336

Online Publication Date: Dec 21, 2010

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We demonstrate an optical probe for detection of porosity inside spool bores of a transmission valve body with diameters down to 5 mm. The probe consists of a graded-index relay rod that focuses a laser beam spot onto the inner surface of the bore. Detectors, placed in the specular and grazing directions with respect to the incident beam, measure the change in scattered intensity when a surface defect is encountered. Based on the scattering signatures in the two directions, the system can also validate the depth of the defect and distinguish porosity from bump-type defects coming out of the metal surface. The system can detect porosity down to a 50-μm lateral dimension and ∼40 μm in depth with >3-dB contrast over the background intensity fluctuations. Porosity detection systems currently use manual inspection techniques on the plant floor, and the demonstrated probe provides a noncontact technique that can help automotive manufacturers meet high-quality standards during production.
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Reducing the pyroelectric effect in lithium niobate Q-switch crystals

Brian K. Brickeen and Charles Shanta

Opt. Eng. 49, 124201 (Dec 23, 2010); http://dx.doi.org/10.1117/1.3520053

Online Publication Date: Dec 23, 2010

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The influences of thermo-chemical reduction processing on the physical properties of lithium niobate are studied. The behavior of the surface resistivity and the induced optical absorption are characterized, with trends indicating a significant reduction in resistivity can be realized before absorption becomes problematic in the 1.0 μm spectral region. The edge localization of the effects in bulk materials is identified, suggesting a central clear aperture of high transmission is possible even when large absorption near the crystal edges is observed. Electro-optical Q-switch crystals were processed with varying degrees of annealing and reduction, leading to the realization of several samples with optimal combinations of modified surface and bulk properties. The highest transmission samples were then tested under transient ambient temperature conditions and compared to unprocessed crystals. The processed samples showed a significant reduction in the transient depolarization of transmitted laser light due to the pyroelectric effect.

Passively Q-switched and mode-locked 1.34-μm Nd:YAG laser with V3+:YAG saturable absorber

Yufei Li, Shengzhi Zhao, Yuming Sun, Huanjun Qi, and Gang Zhang

Opt. Eng. 49, 124202 (Dec 23, 2010); http://dx.doi.org/10.1117/1.3522643

Online Publication Date: Dec 23, 2010

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By using vanadium-ion-doped YAG crystal (V3+:YAG) as a saturable absorber, a xenon-lamp-pumped passively Q-switched and mode-locked (QML) Nd:YAG laser at 1.34 μm is realized in a straight cavity. About 90% modulation depth of mode locking of the pulse is obtained. The pulse energy and the pulse width of the QML laser are measured. Under the plane-wave approximation, considering the pump rate and the stimulated radiation lifetime of the active medium as well as the excited-state lifetime of the saturable absorber, modified coupled rate equations are introduced to reconstruct the xenon-lamp-pumped passively QML laser with V3+:YAG. By solving the equations numerically, the theoretical evaluations are found to be in good agreement with the experimental results. The numerical simulation results demonstrate that the model under the plane-wave approximation is accurate enough to describe the dynamical process of xenon-lamp-pumped passively QML laser with V3+:YAG.
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Phase noise reduction of a semiconductor laser in a composite optical phase-locked loop

Naresh Satyan, Jacob Sendowski, Arseny Vasilyev, George Rakuljic, and Amnon Yariv

Opt. Eng. 49, 124301 (Dec 06, 2010); http://dx.doi.org/10.1117/1.3518077

Online Publication Date: Dec 06, 2010

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The bandwidth and residual phase noise of optical phase-locked loops (OPLLs) using semiconductor lasers are typically constrained by the nonuniform frequency modulation response of the laser, limiting their usefulness in a number of applications. It is shown in this work that additional feedback control using an optical phase modulator improves the coherence between the master and slave lasers in the OPLL by achieving bandwidths determined only by the propagation delay in the loop. A phase noise reduction by more than a factor of two is demonstrated in a proof-of-concept experiment using a commercial distributed feedback semiconductor laser.

In-cell measurements of smoke backscattering coefficients using a CO2 laser system for application to lidar-dial forest fire detection

Carlo Bellecci, Pasquale Gaudio, Michela Gelfusa, Teresa Lo Feudo, Andrea Murari, Maria Richetta, and Leonerdo De Leo

Opt. Eng. 49, 124302 (Dec 17, 2010); http://dx.doi.org/10.1117/1.3526331

Online Publication Date: Dec 17, 2010

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In the lidar-dial method, the amount of the water vapor present in the smoke of the vegetable fuel is detected to reduce the number of false alarms. We report the measurements of the smoke backscattering coefficients for the CO2 laser lines 10R20 and 10R18 as determined in an absorption cell for two different vegetable fuels (eucalyptus and conifer). These experimental backscattering coefficients enable us to determine the error to be associated to the water vapor measurements when the traditional first-order approximation is assumed. We find that this first-order approximation is valid for combustion rates as low as 100 g/s.
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Novel micro-optical collector design for a gas chromatographic detector based on atomic emission spectroscopy

Matthias Gruber, MEMBER SPIE, Michael Bohling, Holger Winkelmann, and Hans Knuppertz

Opt. Eng. 49, 124401 (Dec 06, 2010); http://dx.doi.org/10.1117/1.3516731

Online Publication Date: Dec 06, 2010

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We report a novel micro-optical systems approach for gas chromatographic detection based on plasma excitation of the eluate and subsequent emission spectroscopic evaluation. Specifically, we propose a detector architecture that integrates a microhollow cathode setup and an optical collector system on a common planar microsystems platform. The collector consists of an array of identical imaging systems that surround the microplasma and couple the emitted light side-on into fibers via which it can be fed into a spectrometer. Elliptically shaped reflector profiles ensure nearly aberration-free achromatic imaging and hence a high coupling efficiency. This is confirmed by ray-tracing simulations. An experimental demonstration of the detector module is assembled. The elliptical profiles are milled out of aluminium with diamond tools on an ultraprecision machining center. Experimental tests with a He plasma prove that a higher optical coupling efficieny than with the traditional end-on signal pickup scheme can be achieved.
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Solid immersion lens at the aplanatic condition for enhancing the spectral bandwidth of a waveguide grating coupler

Marcelo B. Pereira, Jill S. Craven, and Sergio B. Mendes

Opt. Eng. 49, 124601 (Dec 07, 2010); http://dx.doi.org/10.1117/1.3520063 | Cited 1 time

Online Publication Date: Dec 07, 2010

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We report a technique to substantially boost the spectral bandwidth of a conventional waveguide grating coupler by using a solid immersion cylindrical lens at the aplanatic condition to create a highly anamorphic beam and reach a much larger numerical aperture, thus enhancing the spectral bandwidth of a free-space propagating optical beam coupled into a single-mode planar integrated optical waveguide (IOW). Our experimental results show that the broadband IOW spectrometer thus created almost doubles (94% enhancement) the coupled spectral bandwidth of a conventional configuration. To exemplify the benefits made possible by the developed approach, we applied the technique to the broadband spectroscopic characterization of a protein submonolayer; our experimental data confirm the enhanced spectral bandwidth (around 380–nm) and illustrate the potentials of the developed technology. Besides the enhanced bandwidth, the broadband coupler of the single-mode IOW spectrometer described here is more robust and user-friendly than those previously reported in the literature and is expected to have an important impact on spectroscopic studies of surface-adsorbed molecular layers and surface phenomena.
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Spectral property of two-photon flux generated by four-photon scattering in photonic-crystal fibers

Hongbo Sun, Xueming Liu, Xiaohong Hu, and Xiaohui Li

Opt. Eng. 49, 125001 (Dec 17, 2010); http://dx.doi.org/10.1117/1.3516732

Online Publication Date: Dec 17, 2010

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Based on the scalar four-photon scattering process, the quantum state of a lightwave at the output of fiber is derived by solving the nonlinear Schrödinger equation with a perturbation theory. The joint spectral function of two photons is achieved from the derived quantum state. The dispersion operator involves the third-order dispersion term in the case that the pump wavelength is close to the zero dispersion wavelength. Simulation results show the first-order approximation of our joint spectral function is in excellent agreement with the complicated exact solution. By analyzing the spectral property of the two-photon flux generated by four-photon scattering in photonic-crystal fibers, it is found that the sign of dispersion has very little influence on the spectrum except the slight modulation instability in the anomalous dispersion domain.

Measured and simulated cutoff wavelengths as a function of core ellipticity for higher order modes in elliptical optical fibers

Søren Herstrøm

Opt. Eng. 49, 125002 (Dec 20, 2010); http://dx.doi.org/10.1117/1.3518079

Online Publication Date: Dec 20, 2010

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Mode splitting of higher order modes in elliptical dielectric waveguides has been addressed theoretically in great detail since the 1960s. This work presents for the first time detailed experimental measurements of mode splitting in elliptical core optical silica fibers, with a semiminor to semimajor ratio ranging from 1.0 to 0.1. The experimental data are compared with numerical simulations obtained from finite element calculations performed on fiber 2-D refractive index profiles from each of the studied fiber pieces.

Hybrid transceiver and repeater using a PANDA ring resonator for nanocommunication

Bunjoung Jukgoljun, Nathaporn Suwanpayak, Chat Teeka, and Preecha P. Yupapin

Opt. Eng. 49, 125003 (Dec 16, 2010); http://dx.doi.org/10.1117/1.3526332 | Cited 1 time

Online Publication Date: Dec 16, 2010

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A novel system of an optical vortex generation using an add/drop multiplexer incorporating with two nanoring resonators is proposed. Such a system is known as a PANDA ring resonator structure, in which the optical vortices (gradient optical fields/wells) can be generated and used to form the photon/atom trapping tools in the same way as the optical tweezers. By controlling some suitable parameters of the input and the control optical pulses, the intense optical vortices can be generated within the PANDA ring resonator, in which the trapped photons/atoms can move dynamically within the system. The trapping force occurrs and is formed by the combination between the gradient field and scattering photons, which we review. A transmitter and receiver can be formed within the same system (device), which is called a transceiver. Finally, the use of the PANDA ring resonator as a hybrid transceiver and repeater for nanocommunication is discussed.

Optical 90-deg hybrid of birefringent crystals for freely propagating laser beams

Lingyu Wan, Yanan Zhi, Yu Zhou, and Liren Liu

Opt. Eng. 49, 125004 (Dec 21, 2010); http://dx.doi.org/10.1117/1.3526334

Online Publication Date: Dec 21, 2010

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An optical 90-deg hybrid of birefringent crystals for freely propagating laser beams is presented. It consists principally of a quarter-wave plate, two pairs of birefringent crystal plates, and a polarization analyzer. The splitting and recombination of the signal and local-oscillator beams are achieved through the birefringence of the crystals, and a 90-deg phase shift is introduced between orthogonally polarized beam components by use of a quarter-wave plate. The optical hybrid has a self-compensating light path, and its correct function is demonstrated in a self-heterodyne measurement setup.

Polarization diversity scheme on spectral polarization coding optical code-division multiple-access network

Chih-Ta Yen, Jen-Fa Huang, Yao-Tang Chang, and Bo-Hau Chen

Opt. Eng. 49, 125005 (Dec 29, 2010); http://dx.doi.org/10.1117/1.3526335

Online Publication Date: Dec 29, 2010

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We present an experiment demonstrating the spectral-polarization coding optical code-division multiple-access system introduced with a nonideal state of polarization (SOP) matching conditions. In the proposed system, the encoding and double balanced-detection processes are implemented using a polarization-diversity scheme. Because of the quasiorthogonality of Hadamard codes combining with array waveguide grating routers and a polarization beam splitter, the proposed codec pair can encode-decode multiple code words of Hadamard code while retaining the ability for multiple-access interference cancellation. The experimental results demonstrate that when the system is maintained with an orthogonal SOP for each user, an effective reduction in the phase-induced intensity noise is obtained. The analytical SNR values are found to overstate the experimental results by around 2 dB when the received effective power is large. This is mainly limited by insertion losses of components and a nonflattened optical light source. Furthermore, the matching conditions can be improved by decreasing nonideal influences.
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Digital holographic recording and reconstruction of large scale objects for metrology and display

Jan Mundt and Thomas Kreis, MEMBER SPIE

Opt. Eng. 49, 125801 (Dec 17, 2010); http://dx.doi.org/10.1117/1.3524238

Online Publication Date: Dec 17, 2010

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Digital holography captures holograms by charge-coupled device or complementary metal-oxide semiconductor cameras, which have a spatial resolution still not reaching that of silver-halide holofilms. Thus, due to the sampling theorem, the angle between the reference and object wave is limited. Only fields coming from small objects, objects far away, or optically reduced fields can be recorded. Here we investigate optical reduction by a system of lenses, and show that a system of two concave lenses results in a drastic reduction of the object-target distance, while the effect of using more lenses is insignificant. Experimental results obtained with Fresnel and lensless Fourier-transform geometry are presented, and implications on holographic interferometric metrology as well as on holographic 3-D television are given.
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Determining the complex index of refraction of an unknown object using turbulence-degraded polarimetric imagery

Milo W. Hyde IV, MEMBER SPIE, Jason D. Schmidt, MEMBER SPIE, Michael J. Havrilla, and Stephen C. Cain, MEMBER SPIE

Opt. Eng. 49, 126201 (Dec 21, 2010); http://dx.doi.org/10.1117/1.3518044

Online Publication Date: Dec 21, 2010

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A novel index-of-refraction material-characterization technique using passive polarimetric imagery degraded by atmospheric turbulence is presented. The method uses a variant of the LeMaster and Cain [J. Opt. Soc. Am. A 25(9), 2170–2176 (2008)] blind-deconvolution algorithm to recover the true object (i.e., the first Stokes parameter), the degree of linear polarization, and the polarimetric-image point spread functions. Nonlinear least squares is then used to find the value of the complex index of refraction that best fits the theoretical degree of linear polarization, derived using a polarimetric bidirectional reflectance distribution function, to the turbulence-corrected degree of linear polarization. To verify the proposed material-characterization technique, experimental results of two painted metal samples are provided and analyzed.
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Extended use of two crossed Babinet compensators for wavefront sensing in adaptive optics

Lancelot Paul and Ajay Kumar Saxena, MEMBER SPIE

Opt. Eng. 49, 126601 (Dec 16, 2010); http://dx.doi.org/10.1117/1.3518068

Online Publication Date: Dec 16, 2010

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An extended use of two crossed Babinet compensators as a wavefront sensor for adaptive optics applications is proposed. This method is based on the lateral shearing interferometry technique in two directions. A single record of the fringes in a pupil plane provides the information about the wavefront. The theoretical simulations based on this approach for various atmospheric conditions and other errors of optical surfaces are provided for better understanding of this method. Derivation of the results from a laboratory experiment using simulated atmospheric conditions demonstrates the steps involved in data analysis and wavefront evaluation. It is shown that this method has a higher degree of freedom in terms of subapertures and on the choice of detectors, and can be suitably adopted for real-time wavefront sensing for adaptive optics.
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Novel effective fuzzy diffusion algorithm for noise removal

Yingtao Zhang, Heng-Da Cheng, Jianhua Huang, and Xianglong Tang

Opt. Eng. 49, 127001 (Dec 06, 2010); http://dx.doi.org/10.1117/1.3516724

Online Publication Date: Dec 06, 2010

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Anisotropic diffusion is widely used for noise reduction. The performance of anisotropic diffusion, in general, depends on the shape of the energy surface. The partial differential equation model is established and analyzed in the continuous domain while is implemented in the discrete domain. Therefore, the anisotropic diffusion bears some fuzziness due to the approximation. We present a novel noise removal algorithm based on fuzzy logic and anisotropic diffusion theory. The experimental results demonstrate that the proposed method has the advantage of maximizing noise reduction and preserving fine details of the images. In addition, the method can enhance the contrast of the images well.

Nonrigid registration based on projected joint entropy combined with gradient similarity

Rafael Henrique Castanheira de Souza, Masao Shimizu, Masatoshi Okutomi, and Shin Yoshimura

Opt. Eng. 49, 127002 (Dec 28, 2010); http://dx.doi.org/10.1117/1.3518073

Online Publication Date: Dec 28, 2010

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Our study proposes a nonrigid image registration method between different color channels in a color image sequence. It minimizes the entropy in a dominant subspace of the joint distribution of two or more images. The proposed algorithm is based on the observation that the displacement between color channels affects only the dominant subspace in the joint distribution of pixel values. We also propose the use of gradient direction to give extra robustness to our similarity function. Experiments estimating motion parameters for B-spline nonrigid deformation models demonstrate the effectiveness of the proposed registration technique.

Support-vector-machine tree-based domain knowledge learning toward automated sports video classification

Guoqiang Xiao, Yang Jiang, Gang Song, and Jianmin Jiang

Opt. Eng. 49, 127003 (Dec 07, 2010); http://dx.doi.org/10.1117/1.3518080

Online Publication Date: Dec 07, 2010

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We propose a support-vector-machine (SVM) tree to hierarchically learn from domain knowledge represented by low-level features toward automatic classification of sports videos. The proposed SVM tree adopts a binary tree structure to exploit the nature of SVM's binary classification, where each internal node is a single SVM learning unit, and each external node represents the classified output type. Such a SVM tree presents a number of advantages, which include: 1. low computing cost; 2. integrated learning and classification while preserving individual SVM's learning strength; and 3. flexibility in both structure and learning modules, where different numbers of nodes and features can be added to address specific learning requirements, and various learning models can be added as individual nodes, such as neural networks, AdaBoost, hidden Markov models, dynamic Bayesian networks, etc. Experiments support that the proposed SVM tree achieves good performances in sports video classifications.

Unmatched projector/backprojector pair for demultiplexing in multipinhole emission computed tomography

Byung Jun Min, Yong Choi, Nam-Yong Lee, Jin Ho Jung, Key Jo Hong, Ji Hoon Kang, Wei Hu, Kisung Lee, MEMBER SPIE, Young Bok Ahn, and Jinhun Joung

Opt. Eng. 49, 127004 (Dec 07, 2010); http://dx.doi.org/10.1117/1.3518081

Online Publication Date: Dec 07, 2010

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Statistically based iterative algorithms such as maximum likelihood–expectation maximization (ML-EM) are used for image reconstruction in single photon emission computed tomography (SPECT). Unmatched projector/backprojector pairs are sometimes used to accelerate the iteration process in the reconstruction algorithm. In this work, we propose and explore the use of an unmatched projector/backprojector pair for demultiplexing in multipinhole SPECT. Several simulations are conducted to evaluate the performance of the proposed method with uniform, hot-rod, and cold-rod phantoms. The proposed method incorporates an unmatched backprojector to utilize selective multiplexed projection data in reconstruction algorithms, while the projector is modeled as accurately as possible to represent realistic imaging geometry and the physical effects of multipinhole SPECT. The root mean square (rms) error and backprojection speed are evaluated to determine an unmatched backprojector. Our results demonstrate that the proposed method provides high-quality multipinhole SPECT images without multiplexing-related artifacts when a well-chosen unmatched backprojector is used.

Global registration and moving objects detection in noisy airborne image sequences

Nader M. Namazi, William J. Scharpf, Jerome Obermark, and James N. Caron

Opt. Eng. 49, 127005 (Dec 28, 2010); http://dx.doi.org/10.1117/1.3520057

Online Publication Date: Dec 28, 2010

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This paper presents a method for registration of noisy airborne images for the purpose of the detection of moving objects. A new iterative algorithm is developed and presented for the correction of geometrical distortion caused by global motion in a scene. A binary hypotheses test is subsequently established using a likelihood ratio test (LRT) to classify the pixels in the corrected image as either locally moving (object motion) or not moving (stationary). The paper also incorporates the use of the Expectation-Maximization method for estimation of statistical image features needed by the LRT. We use and present experiments with real image sequences to validate the analytical developments.

Hough transform relative to a four-dimensional parameter space for the detection of constant velocity target

Jing Hu and Tianxu Zhang

Opt. Eng. 49, 127006 (Dec 17, 2010); http://dx.doi.org/10.1117/1.3522642

Online Publication Date: Dec 17, 2010

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We present a novel Hough transform method for moving point target detection by using a 4-D parameter space. A new representation, which uses four parameters (the distance variable ρ, the angle variable θ, the velocity variable v, and the distance variable S), is proposed for constant velocity target in the 3-D observation space X-Y-T. By estimating velocity, a target trajectory can be transformed into a 4-D parameter space with a limited range of projection options. Our simulation and analysis show that the new algorithm can produce positive results in suppressing noise points with less computational cost.

New entropic thresholding approach using gray-level spatial correlation histogram

Yang Xiao, Zhiguo Cao, and Sheng Zhong

Opt. Eng. 49, 127007 (Dec 28, 2010); http://dx.doi.org/10.1117/1.3526333

Online Publication Date: Dec 28, 2010

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Two-dimensional entropic thresholding methods apply gray-level spatial correlation to thresholding and achieve much better performance than 1-D methods, while suffering from large time consumption. To utilize gray-level spatial correlation in thresholding with less time consumption, we define and describe a new entropic thresholding approach employing the gray-level spatial correlation (GLSC) histogram. The GLSC histogram is determined using the gray value of the pixels and the number of their neighboring pixels of similar gray value, which is different from a 2-D histogram. During the entropic criterion function computation, the entropy yielded by different elements in the GLSC histogram is weighted by a nonlinear weighting function, which we suggest. In the experiment, Kapur's 1-D method and three 2-D methods reported by Abutaleb and Sahoo are employed for comparision. Experiments on many real-world images demonstrate that the proposed method yields equivalent or even better results than 2-D ones while saving time remarkably and significantly outperforms Kapur's 1-D method without too much more time consumption generally.
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Emotion categorization using affective-pLSA model

Shuoyan Liu, De Xu, and Songhe Feng

Opt. Eng. 49, 127201 (Dec 28, 2010); http://dx.doi.org/10.1117/1.3518051

Online Publication Date: Dec 28, 2010

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Emotion categorization of natural scene images represents a very useful task for automatic image analysis systems. Psychological experiments have shown that visual information at the emotion level is aggregated according to a set of rules. Hence, we attempt to discover the emotion descriptors based on the composition of visual word representation. First, the composition of visual word representation models each image as a matrix, where elements record the correlations of pairwise visual words. In this way, an image collection is modeled as a third-order tensor. Then we discover the emotion descriptors using a novel affective-probabilistic latent semantic analysis (affective-pLSA) model, which is an extension of the pLSA model, on this tensor representation. Considering that the natural scene image may evoke multiple emotional feelings, emotion categorization is carried out using the multilabel k-nearest-neighbor approach based on emotion descriptors. The proposed approach has been tested on the International Affective Picture System and a collection of social images from the Flickr website. The experimental results have demonstrated the effectiveness of the proposed method for eliciting image emotions.

Nonparametric membership functions and fuzzy logic for vision sensor-based flame detection

Byoung Chul Ko, Hyun-Jae Hwang, and Jae-Yeal Nam

Opt. Eng. 49, 127202 (Dec 23, 2010); http://dx.doi.org/10.1117/1.3520069 | Cited 1 time

Online Publication Date: Dec 23, 2010

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This paper proposes an advanced fire-flame detection algorithm using camera images for a better performance than conventional sensor-based systems that are limited to a small area. First, candidate flame regions are detected from the captured images using a background model and flame-color model. After forming probability density functions for the intensity variation, wavelet energy, and motion orientation on a time axis, these probability density functions are changed into membership functions for fuzzy logic. Finally, the result function is made by defuzzification, and the probability value of a fire flame is estimated. The proposed algorithm is successfully applied to various fire videos, including indoor and outdoor fires, and shows a better detection performance when compared with other methods.

Stereo system based on a graphics processing unit for pedestrian detection and tracking

Bodam Nam, Sungil Kang, Hyunki Hong, and Changkyoung Eem

Opt. Eng. 49, 127203 (Dec 16, 2010); http://dx.doi.org/10.1117/1.3521254

Online Publication Date: Dec 16, 2010

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This paper presents a novel stereo system, based on a graphics processing unit (GPU), for pedestrian detection in real images. The process of obtaining a dense disparity map and the edge properties of the scene to extract a region of interest (ROI) is designed on a GPU for real-time applications. After extracting the histograms of the oriented gradients on the ROIs, a support vector machine classifies them as pedestrian and nonpedestrian types. The system employs the recognition-by-components method, which compensates for the pose and articulation changes of pedestrians. In order to effectively track spatial pedestrian estimates over sequences, subwindows at distinctive parts of human beings are used as measurements for the Kalman filter.

Fast and robust corner detector based on double-circle mask

Jinhui Lan and Meng Zhang

Opt. Eng. 49, 127204 (Dec 23, 2010); http://dx.doi.org/10.1117/1.3526330

Online Publication Date: Dec 23, 2010

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Image corner detection is one of fundamental problems of computer vision and image processing research. Most of the corner detectors detect too much redundant information and increase unnecessary computational costs. We present a new mask that uses only the margin pixels of two circles. To avoid the unnecessary computing, when the mask is scanning areas of similar intensity, the mask will go on with the next nucleus directly. Then a fast corner detection algorithm based on a double circle mask is proposed. We test the performance of our algorithm on digital signal processing and the experimental results show that our new detector performs better and costs less time than the three other methods to which it is compared.
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Analysis of two novel concepts for multiview three-dimensional displays using one projector

Lawrence Bogaert, MEMBER SPIE, Youri Meuret, MEMBER SPIE, Herbert De Smet, MEMBER SPIE, and Hugo Thienpont, FELLOW SPIE

Opt. Eng. 49, 127401 (Dec 23, 2010); http://dx.doi.org/10.1117/1.3524240 | Cited 1 time

Online Publication Date: Dec 23, 2010

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We present two concepts to create multiview 3-D displays with high spatial and angular resolution at a reasonable system cost. We investigate a rear projection approach using only one projector with a digital micromirror device as a light modulator. The first concept is based on time sequentially illuminating the entire light modulator from different directions. Each illumination direction corresponds to a different viewing zone. We design an illumination system that generates all distinct illumination beams, and a lens system integrated into the projection screen to enlarge the viewing zones. A second concept is based on a projection screen architecture that steers images into different horizontal directions and does not require a directional illumination of the light modulator. In this way, the entire acceptance étendue of the projection system can be used for every image. This is achieved by horizontally moving a double-sided lenticular sheet with respect to a sheet of microlenses with a square footprint. Both concepts are investigated with advanced optical simulations.
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Resonance and zero scattering of light by spherical photonic clusters: analytical approach

Vitaly V. Prosentsov

Opt. Eng. 49, 128001 (Dec 16, 2010); http://dx.doi.org/10.1117/1.3516725

Online Publication Date: Dec 16, 2010

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Light scattering by finite nanostructures is a topic for modern photonics. The scattering can be investigated numerically by performing memory-demanding and long-running computer simulations. When the electromagnetic field inside the nanostructure is quasiperiodic the computations can be thousand times faster. In addition, when the particles in the structure and the distance between the particles is small compared to the incident wavelength, the scattered fields can be calculated even analytically. We study the scattering of light by a photonic cluster made of small particles using quasiperiodicity. The scattered field is calculated analytically and the conditions of the resonance and zero scattering are found. The validity of the obtained results is verified via comparison with the results calculated using the reliable local perturbation method.
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Probability-hypothesis-density filter for multitarget visual tracking with trajectory recognition

Jingjing Wu, Shiqiang Hu, and Yang Wang

Opt. Eng. 49, 129701 (Dec 28, 2010); http://dx.doi.org/10.1117/1.3518084

Online Publication Date: Dec 28, 2010

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The probability-hypothesis-density (PHD) filter as a multitarget recursive Bayes filter has generated substantial interest in the visual tracking field due to its ability to handle a time-varying number of targets. But the target's trajectory cannot be identified within its own framework. To complement the ability of PHD, the auction algorithm is combined to calculate the object trajectories automatically. We present a motion detection, dynamic, and measurement equation, as well as visual multitarget tracking algorithm based on Gaussian mixture probability hypothesis density with trajectory computation in detail. Experimental results on a large video surveillance dataset show that the proposed multitarget tracking framework improves the tracker and recognizes tracks when a variable number of targets appear, merge, split, and disappear, even in cluttered scenes.
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