For reconstructing sweep fingerprint sequences, we propose a coarse-to-fine image registration scheme, which first uses the block-matching method as the preregistration and then adopts the curvature-based elastic registration as a fine estimation of nonlinear distortions between two consecutive frames. With respect to two existing state-of-the-art approaches, the new scheme becomes more robust against distortions and therefore the reconstruction accuracy is improved.
A kernel-based metric measuring tracking reliability that is based on discriminative components of a kernel target model and kernel mutual information is presented. The discriminative components of the kernel target model are selected by computing the log-likelihood ratios of class-conditional sample densities of these components from a target region and background sampled region. The components selection process is embedded in a metric with kernel mutual information of the target regions of the initial frame and current frame in video infrared target tracking for online evaluation of the tracking reliability. Experimental results have shown that the metric can effectively characterize target tracking results as good or bad.
For fabricating the metallic mesh on a spherical substrate, a method that can adjust the center of a sphere to its spin axis is presented. A grating is used for the light splitting and uniting, and fixed on the center of spherical substrate. First, a laser beam is diffracted by the grating and splits several beams, and a -order beam of diffracted beams arrives the substrate and returns to the grating. They are diffracted by the grating again, and an interference pattern is obtained in the overlapped region of two diffracted beams. A polarization prism and a wave plate deflect the coherent beam from former incidence direction, and the interference pattern is displayed on a screen by the transform of a CCD detector. While the curvature center of the spherical substrate aligns with its spin axis, the interference pattern is still when the substrate is revolving about its spin axis, or else the interference pattern will alter with the revolving of substrate. The change scale of interference fringes also corresponds with the error of alignment.
In survivable wavelength-division multiplexed networks, the backup resource can be shared by the primary light paths, which is called primary-backup sharing. We find that primary-backup sharing can have an effect on the link availability. We focus on routing under dynamic availability of the wavelength resource while the requested reliability of traffic has to be met, using the modified shortest path algorithm. We propose a new algorithm called the dynamic link availability algorithm and evaluate the performance of the proposed algorithm on the NSFNET.
We report and present an experimental investigation of spatially and thermally dependent self Q-switching effects generated in cavity. The main application for the investigated effect is generation of an efficient Q-switched lasing in a crystal that may be realized without the need for a saturable absorber module.
We describe how to use Markov chain Monte Carlo simulation (MCMC) to accurately estimate the outage probability of the optical communication system compensated by higher-order optical polarization mode dispersion (PMD) compensators. Markov chain fiber channel samples can drastically reduce the number of simulations required to estimate the outage probability of the compensated systems to or less. Using MCMC, the efficiency of our proposed higher-order optical PMD compensator is proved further, and the accuracy of MCMC is affirmed.
Half a century has passed since Theodore Maiman's small ruby rod crossed the threshold of laser emission. The breakthrough demonstration earned headlines, but in the early years the laser was called "a solution looking for a problem," and there was a germ of truth in the joke. Years of development since then have vastly improved laser performance,and tremendously increased their variety, earning lasers important roles in scientific research, consumer products, telecommunications,engineering, medicine, materials working, and a host of other applications. This article reviews the highlights of those developments and puts them into context, showing how laser technology has evolved to meet application requirements.
Examining classic theories, experimental methods, and practical formulas for exploration of the core topics in nonlinear optics, the second edition of this acclaimed text was extensively revised to reflect recent advances in the analysis and modification of material properties for application in frequency conversion, optical switching and limiting,