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Transparent optical networks (TON) are becoming increasingly attractive, but transparency introduces security threats, e.g., intrachannel crosstalk attack, to optical networks. In this letter, three attack scenarios, i.e., attack propagation within an optical cross connect (OXC), the secondary attacker traverses successive OXCs and original attacker traverses successive OXCs, are investigated. The scenarios accompanied with gain competition attack are also simulated as comparison. Bit-error-rate (BER), and eye diagram penalties are estimated via VPItransMaker^TM. Our work proved that the attack signal will propagate intrachannel crosstalk attack to successive three OXCs but with limited two stages of optical switches in each OXC. The BER will be somewhat higher in case gain competition attack exists. The results will be useful for future managing, planning, and designing on TONs.

A method for designing narrow-band reflecting filters has been proposed and it can be easily used to design the reflectance spectrum shapes of multilayer structures by turning the optical thicknesses of layers from regular into irregular. In this paper, we report two design examples of such narrow-band filters by the method and obtain the results of experiment accord with that of theory very well.

The field of image-based shape measurements using structured illumination has been an active research area for several decades now. A lot of different methods are widely used e.g. for industrial inspection, surveillance as well as multimedia purposes. Usually, short measurement times and high correspondence accuracy are mutually exclusive properties, due to the limitations of the used projection technology. Using a standard stereo-photogrammetry approach, as well as a simple, yet powerful structured light projection concept based on a slide-projector, we demonstrate an acquisition rate of more than 700 dense and accurate 3D measurements per second.

A multimode interferometer based-fiber optic sensor with a silica tube section aimed to measure refractive index (RI) variations of surrounding liquids is presented. The sensing head is a silica tube section fusion spliced to single mode fibers operating in transmission. In the splice regions tapers were made to allow the light to be guided in the silica tube while the core is formed by air. This configuration permits measurements of refractive index variations with sensitivities of 101.1, 106.29, and 107.97 nm/RIU considering resonances with different wavelengths. The same resonances were tested with temperature variations with sensitivities achieved of 7.8, 8.7, and 9.3 pm/ °C, respectively. The spectral variation associated with one degree temperature change corresponds to a refractive index change of ~8 × 10^-5, proving the low temperature dependence compared with sensitivity to RI variations.

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The present work deals with the analysis of problems and potentials of laser vibrometer measurements inside vehicle cabins in running conditions, with particular reference to helicopters where interior vibro-acoustic issues are very important. This paper describes the results of a systematic measurement campaign performed on an Agusta A109MKII mock-up. The aim is to evaluate the applicability of scanning laser Doppler vibrometer (SLDV) for tests in simulated flying conditions and to understand how performances of the technique are affected when the laser head is placed inside the cabin, thus being subjected to interfering inputs. First a brief description of the performed test cases and the used measuring set-ups are given. Comparative tests between the SLDV and accelerometers are presented, analyzing the achievable performances for the specific application. Results obtained measuring with the SLDV placed inside the helicopter cabin during operative excitation conditions are compared with those performed with the laser lying outside the mock-up, these last being considered as "reference measurements." Finally, in order to give an estimate of the uncertainty level on measured signals, a study linking the admitted percentage of noise content on vibrometer signals due to laser head vibration levels will be introduced.

In automotive industry there is an interest of controlling the shape of a large number of identical components on-line in the manufacturing process. We propose a method to do this by capturing a digital hologram of the object and then using information from its computer aided design (CAD) model to calculate the shape and determine the agreement between the manufactured object and the CAD-model. The holographic recording of the object is done using dual wavelengths with a synthetic wavelength of approximately 400 μm. The optical measurement results in a wrapped phase map with the phase values in the interval [ − π, π]. Each phase interval represents a depth distance on the object of about 0.2 mm. The phase unwrapping is done iteratively using information from the CAD-model. This implies that it is possible to measure large discontinuities on the surface of the measured object. The method also gives a point-to-point correspondence between the measurement and the CAD-model which is vital for tolerance control.

Optical techniques are well suited for the measurement of microcomponents but give accurate results only when calibrated systems are used. We present a strategy for the calibration of setups to be used for the measurements of microsystems. We develop, at first, standard reference devices whose out-of-plane and in-plane displacements are precisely reproducible when submitted to standard loadings. These reference devices have been manufactured and tested by optical techniques and may be used for the calibration of optical measuring systems. Furthermore, a detailed discussion of the measurement uncertainty, according to the ISO's "Guide of Expression of Uncertainty in Measurement," is given.

We describe how a shape-measurement system (SMS) based on fringe projection can be combined with a two-dimensional digital image correlation (DIC) technique to accurately measure both surface profile and displacement fields at the same time. Whereas the measurement of all three displacement components by traditional DIC requires the use of at least two cameras, the approach presented here provides the full three-dimensional (3-D) displacement field from a single-camera, single-projector SMS with no additional hardware requirements. Furthermore, the single-pixel spatial resolution of the fringe projection technique can be exploited to prevent the correlation peak-splitting phenomenon that occurs when a DIC subimage straddles a global geometrical discontinuity. Thus, unlike traditional 3-D DIC techniques, the proposed method can measure displacement fields on discontinuous surfaces as easily as on smooth ones. Details of the algorithm are given together with experimental results of a rigid-body translation test. Measurements made during a routine fatigue test on a part of a wing panel are also presented.

Shape measurements and strain distribution measurements are important for analyzing the behavior of a rotating tire. Recently, a two-dimensional phase analysis method using phase-shifting moiré patterns, which are generated computationally from a two-dimensional grating image, was proposed. This method is well suited to the dynamic shape and strain measurement because the phase can be accurately obtained from a two-dimensional grating image. We show that it is possible to analyze the strain distribution and shape measurements of a moving object using a grating pattern attached to the surface of the specimen, and a dynamic shape and strain measurement system using the sampling moiré method is developed in this paper. The principle of the method and the experimental results of the method when applied to a rotating object are shown.

A variety of techniques have been developed to measure the three-dimensional shape of an object using structured illumination. The measurement of objects with diffusely reflecting surfaces by means of projected patterns can be considered a standard technique. Also more recently, methods for the measurement of specularly reflecting or transparent surfaces by evaluation of the images of regular patterns have been published. In this paper, we suggest a systematic treatment of all of these methods as generalized active or passive triangulation techniques.

Advances in emerging technologies of microelectromechanical systems (MEMS) and nanotechnology, especially relating to the applications, constitute one of the most challenging tasks in today's micromechanics and nanomechanics. In addition to design, analysis, and fabrication capabilities, this task also requires advanced test methodologies for determination of functional characteristics of devices produced to enable verification/validation of their operation, as well as refinement and optimization of specific designs. In particular, development of microdevices requires sophisticated tools, especially as these devices apply to transportation industry because of stringent safety and reliability requirements. These tools can be categorized as analytical, computational, and experimental. Solutions using the tools from any one category alone do not usually provide necessary information on MEMS, and extensive merging, or hybridization, of the tools from different categories is used. One of the approaches employed in this development of structures of contemporary interest is based on a combined use of the analytical, computational, and experimental solutions methodology. Development of this methodology was made possible by recent advances in optoelectronic methodology, which was coupled with the state-of-the-art computational methods, to offer a considerable promise for effective development of various designs. This approach facilitates characterization of dynamic and thermomechanical behavior of the individual components, their packages, and other complex material structures.In this paper, recent advances in optoelectronic methodology for microscale measurements are described and their use is illustrated with representative examples.

The success of optical multiple-input-multiple output (MIMO) systems in wireless communications has motivated interesting investigations of MIMO in optical fiber communications. This paper reviews various optical MIMO techniques in multimode fiber.

The image Fourier transform is widely used for defocus and astigmatism correction in electron microscopy. The shape of a power spectrum (the square of a modulus of image Fourier transform) is directly related to the three microscope controls, namely, defocus and twofold (two-parameter) astigmatism. We propose a new method for power-spectrum orientation identification. The method is based on the three measures that are related to the microscope's controls. The measures are derived from the mathematical moments of the power spectrum and is tested with the help of a Gaussian benchmark, as well as with the scanning electron microscopy experimental images. The method can be used as an assisting tool for increasing the capabilities of defocus and astigmatism correction a of nonexperienced scanning electron microscopy user, as well as a basis for automated application.

We propose a design of a Mueller-matrix-microscopic system that can efficiently capture the parameter image with two liquid-crystal modulators (LCMs). The usage of the LCMs can significantly reduce the measurement time for Mueller-matrix parameters. This system employs one LCM to realize real-time measurement of all subimages derived from the Stokes vector and the other one to change the light sources. Seven experimental results, acquired by using incident light with LCM-modulated light sources, are enough for biological research. An error analysis for m44 of the Mueller matrix is involved in order to present the error evaluation. The corresponding error evaluation shows that the measurement errors could be controlled under 0.07 deg.

In this paper, we report the theoretical analysis of different types of plasmonic structures with the main emphasis on the coupled plasmon waveguide resonance due to several advantages offered by the same compared to other structures. Multiple resonance dips are found to increase with the increase in the dielectric layer thickness and this progressive nature of the dips can be efficiently utilized to characterize the dielectric material within a composite multilayer plasmonic structure. Supporting simulation results carried out in the MATLAB environment are also provided to validate the proposed application.

We propose a molecular dynamics method incorporating a variable radius technique to generate the dot patterns printed on the bottom surface of the light guide plate for the large scale edge-lit light-emitting diode (LED) backlight unit. In addition, this method is also incorporated with the cell division technique and r-cut technique to help reduce the computational time for optimization. The process, including adjustment in the dot radius according to the feedback from an illuminance result of the optical software, which compares to the other methods, can reduce the time for computation and the process can be incorporated into an optical design phase quite easily. By employing the above method, the time for obtaining a random dot distribution for a 42-in. LED backlight with a thickness of 4 mm and uniform illuminance of 80%, is significantly shortened.

The relationship between spatial localization and bichromatic emission phenomena in one-dimensional (1D) active random media with gain is investigated by simultaneously solving Maxwell's equations and rate equations of electronic population. Results indicated that the increase of the concentration of the dye increases the spectral intensity of the dimer and the increase of the pump energy produces major radiative and nonradiative energy transfers from monomers to dimers. The increase of the ratio of the concentration of monomer to that of dimer would reduce the intensity of localization and increase the threshold of lasing mode. The competition between two lasing modes in 1D active random media can be controlled by local pumping. The results agree very well with the experimental data and offer a useful method for mode-selection.

A moving-diode-method and a moving-profiler-method for laser diode astigmatism measurement are theoretically analyzed. A two-lens measurement setup that can reduce the laser beam to a geometric optics beam is proposed. The proposed setup can utilize geometric optics to analyze and thereby significantly simplify the measurement process for both methods. The result of this paper is also useful to the design of laser beam focusing optics.

Using laser direct writing in combination with chemical vapor deposition to produce nanometer scale electronics holds several advantages over current large scale photolithography methods. These include single step electrical interconnect deposition, mask-less patterning, and parallel processing. When taken together they make quick production of individualized electronic circuits possible. This work demonstrates the ability of combining laser direct write and chemical vapor deposition to produce silicon wires a few hundred nanometers wide. Optimized parameters will be discussed, with a particular emphasis paid to the laser-material interactions. The feasibility for electronic applications will be shown by examining the deposition formation on a silicon dioxide surface without degrading the surface's integrity, and by evaluating the resistivity of the deposited silicon wires.

In the satellite-to-ground downlink lasercom systems, efficient coupling of atmospherically distorted spatial light into single-mode fibers is a key technology for fiber-coupled optical receiver. Statistical distribution of fiber-coupling efficiency is important to analyze the performance of a receiver. We use the simulation of beam propagation to examine statistical distribution of fiber-coupling efficiency for the satellite-to-ground downlink. The distributions of the fiber-coupling efficiency for different numbers of speckles are obtained, and the cumulative density functions of the fiber-coupling efficiency are also given. In order to validate the accuracy of numerical simulation method, the dependence of average fiber-coupling efficiency on the ratio of lens size to speckle size is attained, which is highly consistent with the prior theoretical works. The results will be helpful in the design of the satellite-to-ground downlink lasercom system based on fiber-coupling technology.

We have presented a single-fiber dense wave-division multiplexing (DWDM) ring scheme with wavelength reuse for uplink and optical signal generation for downlink. Instead of using a new laser for uplink, the wavelength already used for wavelength beating to generate the downlink signal in optical domain is reused for uplink. Algorithms for power optimization using Erbium-doped fiber amplifier, wavelength routing, and wavelength assignment are developed and simulated. The DWDM-radio over fiber scheme reusing the wavelength can support the data rate in the range of 1 Gbps. Fifteen remote antenna units (RAUs) are simulated in this scheme; however, these can be increased by adding more wavelengths. The proposed scheme simplifies the architecture or RAUs, decreases the overall cost while enhancing the bandwidth and operational flexibility of radio over fiber systems.

A 145-m long microstructured optical fiber taper was fabricated on the industry drawing tower. The fiber taper had good uniformity of structure as the outer diameter decreased from 110 to 80 μm. Its optical attenuation was measured 52 dB/km at 1060 nm, and the zero dispersion wavelengths along the slow axis were calculated decreasing from 1000 to 915 nm. Watt-level supercontinuum spanning from 430 to 2050 nm was obtained as the fiber taper pumped by a 1064 nm picosecond laser source. The nonlinear mechanism of spectral broadening is carefully investigated with the support of numerical simulations.

In this paper an 8×1 array waveguide grating-wavelength division multiplexing (AWG-WDM) is optimized for its applications in WDM networks, with the wavelength selective switch as the multiplexer/demultiplexer. With the new method of optimization proposed in this work, a higher bandwidth and lower crosstalk and insertion loss are achieved. The procedure of optimization for finding the best parameters such as the waveguide separation at the output circle, a new structure for Rowland circle, a new structure for the tapered waveguide, and displacement of the foci of the Rowland circle from its standard construction are presented and the results are discussed. We designed a silica-based 8 channel AWG-WDM with the channel spacing of 1.6 nm and the central wavelength of 1550 nm. The occupied area of the phased arrayed waveguides is 2.2 × 1.3 cm², and the total device size is 3.6 × 1.28 cm². The 3dB bandwidth of AWG-WDM is 3.31 × 10⁻⁴ μm. The insertion loss of the side channels (1 or 8) is about 2.65 dB for this design, where it is about 3.77 dB for the device based on the standard Rowland circle structure.

A novel carrier-suppressed return-to-zero frequency shift keying (CSRZFSK) transmitter that can operate at 40 Gb/s and above is proposed for the first time. The transmission characteristics of the CSRZFSK signal at 40 Gb/s compared with differential quadrature phase shift keying (DQPSK) signal and amplitude shift keying (ASK) signal are investigated under different dispersion management. Simulation results show that CSRZFSK has the best nonlinear tolerance and longest transmission distance when compared with DQPSK and ASK signals. A 40 Gb/s CSRZFSK signal gives only a 0.1 dB sensitivity penalty while DQPSK and ASK give 0.6 and 0.7 dB, respectively.

In this paper, we propose a comparative performance study to characterize the transmission of multiple subcarrier modulation signals with different M-ary phase shift keying (M-ary PSK) schemes over a radio-on-free-space optical system using the aperture averaging (AA) technique. First, we derive modified expressions for carrier-to-noise and distortion ratio (CNDR), outage probability, and bit-error rate (BER) based on the AA technique and take into consideration the laser diode nonlinearity effect. We also show that there is a design trade-off between the receiver lens aperture and the required average CNDR to achieve a given average BER, ensuring substantial scintillation fade reduction. Further, we perform a comparison between different M-ary PSK modulation schemes, i.e., BPSK, QPSK, and 16-PSK, to characterize the achieved performance improvement by using the AA technique. We found out that when higher order PSK modulation techniques are used such as 16-PSK, the fading reduction is far less impressive than that for schemes employing smaller constellation sizes such as BPSK and QPSK. We thus conclude that for more complex modulation techniques no matter how large the receiver aperture size, the accepted BER level cannot be attained only with the use of the AA technique.

This study analyzes a photonic ultrawideband pulse generator by using a dual-parallel Mach-Zehnder modulator. A simple configuration capable of generating two popular types of ultrawideband pulse shape, Gaussian monocycle and doublet, is proposed. The generated ultrawideband pulses have very high quality, and the exact waveform is tunable with respect to parameter settings. By changing the time delay between two-path driving pulses applied to the upper and lower sub-Mach-Zehnder modulator of the dual-parallel Mach-Zehnder modulator, the generated ultrawideband pulses can be switched from Gaussian monocycle to doublet. The proposal is first analyzed and then validated by simulations. Results of the study demonstrate that it can offer a realistic solution to photonic ultrawideband pulse generation.

Based on an asynchronously undersampling system, we present a novel bit pattern monitoring technique in terms of its performance analysis and the implementation aspects. Relying upon an finite impulse response (FIR) filter assisted fine synchronization of the acquired samples, the technique can significantly reduce the random walk clock drift between data signal and sampling source compared to a conventional fine synchronization using a fixed time step. For the performance analysis of this technique, we first present an intuitive understanding of the principle of the FIR filter method under consideration of the filter frequency response. We find that the frequency response of the FIR filter simply serves to extract the spectral component at the aliasing frequency found in the periodogram and diminish all other frequency components. Then we test the tracking limit and discuss the optimized filter length choice of the new bit pattern monitoring technique through numerical examples. It turns out that the optimal filter length is chosen as the one which minimized the measured jitter and can be found iteratively. Finally, we present an experimental verification of this FIR bit pattern synchronization method by measuring and reconstructing bit patterns of 40 Gb/s nonreturn-to-zero and 160 Gb/s return-to-zero data signals, respectively.

A grating interferometer that uses the high diffraction orders in conjunction with a Twyman-Green commercial interferometer is used for the measurement of in plane movement of gratings. The high diffraction orders ensures the amplification of the measurement precision with a factor equal to the diffraction order of the measurement in principle, because no imaging of features marking the beginning and the end of the measured length feature is necessary, and therefore the resolution limits associated with microscope imaging are eliminated.

Access to both the phase and intensity of an image can be provided using digital holographic (DH) imaging techniques. Recently, the difference of two holograms captured with two appropriately related wavelengths was demonstrated to produce the Laplacian of an object field. Applying telecommunication lasers the feasibility of infrared (IR) DH and DH Laplacian reconstruction and the associated theoretical analyses are presented. This is achieved by combining a tunable mid-IR laser source and mid-IR sensitive InGaAs-based digital camera.

A differential deposition technique was investigated as a way to minimize axial figure errors in full-shell, grazing-incidence, reflective x-ray optics. These types of optics use a combination of off-axis conic segments-hyperbolic, parabolic, and/or elliptical, to reflect and image x-rays. Several such mirrors or "shells" of decreasing diameter are typically concentrically nested to form a single focusing unit. Individual mirrors are currently produced at Marshall Space Flight Center using an electroforming technique, in which the shells are replicated off figured and superpolished mandrels. Several factors in this fabrication process lead to low- and mid-spatial frequency deviations in the surface profile of the shell that degrade the imaging quality of the optics. A differential deposition technique, discussed in this paper, seeks to improve the achievable resolution of the optics by correcting the surface profile deviations of the shells after fabrication. As a proof of concept, the technique was implemented on small-animal radionuclide-imaging x-ray optics being considered for medical applications. This paper discusses the deposition technique, its implementation, and the experimental results obtained to date.

This study is to investigate a new representation of a partition of an image domain into a number of regions using a level set method derived from a statistical framework. The proposed model is composed of evolving simple closed planar curves by a region-based force determined by maximizing the posterior image densities over all possible partitions of the image plane containing three terms: a Bayesian term based on the prior probability, a regularity term adopted to avoid the generation of excessively irregular and small segmented regions, and a term based on a region merging prior related to region area, which is applied to allow the number of regions to vary automatically during curve evolution and therefore can optimize the objective functional implicitly with respect to the number of regions. This formulation leads to a system of coupled curve evolution equations, which is easily amenable to a level set implementation, and an unambiguous segmentation because the evolving regions form a partition of the image domain at all times during curve evolution. Given these advantages, the proposed method can get good performance and experiments show promising segmentation results on both synthetic and real images.

Digital watermarking has received extensive attention as a new method of protecting multimedia content from unauthorized copying. In this paper, we present a nonblind watermarking system using a proposed dynamically weighted fuzzy c-means (DWFCM) technique combined with discrete wavelet transform (DWT), discrete cosine transform (DCT), and singular value decomposition (SVD) techniques for copyright protection. The proposed scheme efficiently selects blocks in which the watermark is embedded using new membership values of DWFCM as the embedding strength. We evaluated the proposed algorithm in terms of robustness against various watermarking attacks and imperceptibility compared to other algorithms [DWT-DCT-based and DCT- fuzzy c-means (FCM)-based algorithms]. Experimental results indicate that the proposed algorithm outperforms other algorithms in terms of robustness against several types of attacks, such as noise addition (Gaussian noise, salt and pepper noise), rotation, Gaussian low-pass filtering, mean filtering, median filtering, Gaussian blur, image sharpening, histogram equalization, and JPEG compression. In addition, the proposed algorithm achieves higher values of peak signal-to-noise ratio (approximately 49 dB) and lower values of measure-singular value decomposition (5.8 to 6.6) than other algorithms.

One major problem of contour-based tracking is how to evaluate the accuracy of tracking results due to nonrigid and deformative properties of contours. We propose a shape context-based evaluation measure that considers the semantic shape similarity between the tracked contour and ground-truth contour. In addition, a pyramid match kernel is introduced for shape histogram matching, which can effectively deal with the contours with different scales. Experimental results demonstrate, compared to two start-of-art evaluation measures, our measure effectively captures the local shape information and thus is more consistent with human vision.

Based on image sharing with utilization of the set partitioning in hierarchical trees (SPIHT)-generated bit stream of integer wavelet transform coefficients and the Shamir threshold scheme over a Galois field, we present a new scheme for secure image transmission. Our algorithm integrates the Chinese remainder theorem with a control code idea to design check bits for authentication and error correction and embeds the produced shadows and check bits into cover images to form stego images for transmission. Moreover, our algorithm adopts the advantages of SPIHT features to generate compact shadows with progressive reconstruction. As a result, the algorithm simultaneously possesses high performance of both authentication and error correction and is highly suitable for image transmission over networks in noisy channels, reaches excellent visual quality of stego images, and achieves real time progressive and perfect reconstruction of the secret image. Experimental results have demonstrated these promising features of the proposed method.

Various tone reproduction operators have been proposed to display high dynamic range images on low dynamic range (LDR) devices. The gradient domain operator is a good candidate due to its capability of reducing the dynamic range and avoiding common artifacts including halos and loss of image details. However the gradient domain operator requires high computational complexity and often introduces low-frequency artifacts such as reversal of contrast between distant image patches. In order to solve these problems we present a new gradient domain tone reproduction method which adopts an energy functional with two terms one for preserving global contrast and the other for enhancing image details. In the proposed method the LDR image is obtained by minimizing the proposed energy functional through a numerical method. Simulation results demonstrate that the proposed method can not only achieve the significantly reduced computational complexity but also exhibit better visual quality as compared with conventional algorithms.

Under pedestrian and vehicle mixed traffic conditions, the potential accident rate is high due to a complex traffic environment. In order to solve this problem, we present a real-time cognitive vision system. In the scene-capture level, foreground objects are extracted based on the combination of spatial and temporal information. Then, a coarse-to-fine algorithm is employed in tracking. After filtering-based normal tracking, problems of the target blob missing, merging, and splitting are resolved by the adaptive tracking modification method in fine tracking. For greater robustness, the key idea of our approach is adaptively adjusting the classification sensibility of each pixel by employing tracking results as feedback cues for target detection in the next frame. On the basis of the target trajectories, behavior models are evaluated according to a decision logic table in the behavior-evaluation level. The decision logic table is set based on rules of real scenes. The resulting system interprets different kinds of traffic behavior and warns in advance. Experiments show robust and accurate results of abnormality detection and forewarning under different conditions. All the experimental results run at real-time frame rates (⩾25 fps) on standard hardware. Therefore, the system is suitable for actual Intelligent Traffic System applications.

In the endless hot rolling process, camber is a significant defect where camber is flatness asymmetries produced by nonuniform distribution of rolling pressure. This kind of defect may not only cause clogging of the finishing mill, but also visible defects, such as bar edge folds, edge cracks, holes, and scrapes. It is important to measure the exact camber values of the overall shape and head/tail part of steel bars to reduce camber for hot-rolled steel bars. We introduce a vision-based camber measurement system based on two-area-scan charge-coupled device (CCD) cameras and proposes a camber-detection algorithm to achieve the optimal cutting-line, the overall bar shape, and camber values from the obtained image. The proposed algorithm consists of three parts: optimal cutting-line detection, image-stitching, and camber detection. The optimal cutting-line detection part determines the cutting line of the head/tail part of the bar for continuous joining between steel bars. The image-stitching part obtains the overall shape of a hot-rolled steel bar with continuous image sequence obtained by two-area-scan CCD cameras. The camber-detection part measures head camber, tail camber, and whole camber of the steel bar. Through the proposed camber-detection algorithm, the system not only satisfies a time constraint for detecting the camber of the steel bar but also obtains the optimal cutting line, the overall bar shape, and the camber values.

A novel core-based fingerprint indexing scheme for embedded systems is presented in this paper. Our approach is enabled by our new precise and fast core-detection algorithm with the direction map. It introduces the feature of CMP (core minutiae pair), which describes the coordinates of minutiae and the direction of ridges associated with the minutiae based on the uniquely defined core coordinates. Since each CMP is identical against the shift and rotation of the fingerprint image, the CMP comparison between a template and an input image can be performed without any alignment. The proposed indexing algorithm based on CMP is suitable for embedded systems because the tremendous speed up and the memory reduction are achieved. In fact, the experiments with the fingerprint database FVC2002 show that its speed for the identifications becomes about 40 times faster than conventional approaches, even though the database includes fingerprints with no core.

A well-established scheme for target detection in infrared (IR) surveillance systems consists of applying a suitable decision rule on the images with background clutter previously removed. Background removal is accomplished by subtracting, from the original image, the estimate of the spatially varying background signal obtained by a background estimation algorithm (BEA). The overall target detection performance is strongly influenced by the effectiveness of the employed BEA. Particularly, the BEA and its design parameters should be chosen so as to get an accurate estimate of the background signal and to avoid biases caused by the possible presence of targets (target leakage). In this work, we present a novel method for the choice and setting of the best performing background removal technique for the detection of dim point targets. The proposed procedure is based on the simulation of dim targets implanted on an acquired sample image representing the scenario of interest. The choice of the best performing BEA is made by exploring the performance of the detection scheme for several configurations of the characteristic parameters of the BEAs. The effectiveness of the BEA selection procedure is evaluated in two case studies where real image sequences acquired by IR cameras are employed. The results confirm the benefits introduced by the proposed technique. Indeed, the performance of the IR detection system with the BEA tuned according to the proposed selection criterion is improved in that the number of false alarms is reduced up to 2 orders of magnitude compared with BEAs in other common configurations.

An offline feature selection and evaluation mechanism is used in order to develop a robust visual tracking scheme for sea-surface and aerial targets. The covariance descriptors, known to constitute an efficient signature set in object detection and classification problems, are used in the feature extraction phase of the proposed scheme. The performance of feature sets are compared using support vector machines, and those resulting in the highest detection performance are used in the covariance based tracker. The tracking performance is evaluated in different scenarios using different performance measures with respect to ground truth target positions. The proposed tracking scheme is observed to track sea-surface and aerial targets with plausible accuracies, and the results show that gradient-based features, together with the pixel locations and intensity values, provide robust target tracking in both surveillance scenarios. The performance of the proposed tracking strategy is also compared with some well-known trackers including correlation, Kanade-Lucas-Tomasi feature, and scale invariant feature transform-based trackers. Experimental results and observations show that the proposed target tracking scheme outperforms other trackers in both air and sea surveillance scenarios.

Normalcy decision in video security involves highly uncertain phenomena due to its inherited insufficient knowledge, intrinsic ambiguity in human cognition, measurement error, etc. This paper presents a hierarchical spatiotemporal trajectory modeling for dynamic trajectory analysis using sparse trajectory data. The trajectory data is assumed to be given by people detection and tracking methods, which are also challenging issues due to occlusion, noise, illumination changes, etc. The proposed method partitions the trajectory feature space into the attributes of trajectory position, direction, and speed. Inherent uncertainty of video trajectory is tackled by employing the uncertainty propagation model of a trajectory segment and Markov random field in analyzing the uncertainty attributes of object movement direction and speed. The proposed method can be used in online learning for incremental adaptation as well as offline learning for optimality guarantee. The method was evaluated using both synthetic trajectories and video streams of multiple people movements acquired from multiple video cameras developed by GE Global Research Center and KAL beta sites. Extensive experiments were performed using video sequences in real world and synthesized trajectories, which achieved very encouraging results.