Showing papers in "Optics and Lasers in Engineering in 2019"

TL;DR: Simulation and performance analysis verify that the new 2D-SLIM modulation map based on the improved two-dimensional closed-loop modulation coupling model has acceptable compression, high security and low time complexity.

TL;DR: Experimental results show that the proposed algorithm improves encryption efficiency, has good security performance, and can resist common attack methods.

TL;DR: CAE-SGAN is proposed to classify surface defects of steels based on Convolutional Autoencoder and semi-supervised Generative Adversarial Networks, and the results indicate that it had yielded best performances compared with traditional methods.

TL;DR: In this article, Long-range surface plasmon resonance (LRSPR) sensor is characterized by high sensitivity, high detection accuracy, flexible design, label-free, and real-time analysis.

TL;DR: A compact yet effective convolutional neural network model, which emphasizes the training of low-level features and incorporates multiple receptive fields, to achieve fast and accurate steel surface defect classification and adopts the pre-trained SqueezeNet as the backbone architecture.

TL;DR: Simulation results demonstrate that using half of indexes for permutation and diffusion make the proposed algorithm very fast and also using DNA sequence encoding gives the algorithm enough power to resist against common attacks in the era of image encryption.

TL;DR: Experimental results demonstrate the effectiveness and reliability of the proposed optical image compression and encryption scheme with considerable compression and security performance.

TL;DR: Under the proposed framework, the proposed encryption scheme is highly sensitive to minor differences in both secret key and plain image, resulting in resisting chosen/known plaintext attacks effectively, comparing with existing approaches in literature.

TL;DR: A semi-supervised learning (SSL) defect classification approach based on multi-training of two different networks: a categorized generative adversarial network (GAN) and a residual network and the GAN to generate a large number of unlabeled samples is proposed.

TL;DR: The results presented here provide both theoretical and practical support for advancements in multi-vision applications such as optical measurement, real-time target tracking, quality monitoring, and surface data acquisition.

TL;DR: In this article, the effects of CeO2 addition on the phase composition, microstructure, microhardness, and wear properties of the Ti-based composite coatings reinforced with TiC/Ti2Ni were investigated by X-ray diffraction, optical microscopy, scanning electron microscopy (SEM), Vickers hardness testing, and friction wear testing.

TL;DR: An optical approach of silhouette-free multiple-image encryption based on interference is proposed, with two layers to enhance the level of security, by considering the fractional order as an additional key.

TL;DR: In this paper, a portable laser sensor for trace ammonia (NH3) is developed based on near-infrared laser absorption spectroscopy, which is implemented by a system-on-chip based on field-programmable gate array.

TL;DR: In this paper, an extrinsic Fabry-Perot interferometric (EFPI) based optical fiber sensor for downhole pressure monitoring is presented, which can provide a resolution of 0.08 nm over a dynamic range of 3 mm.

TL;DR: In this article, the progress of numerical simulations spanning over three distinct stages of the process to model powder flow dynamics, melt pool and clad properties is reviewed and some of the underlying assumptions in the current numerical models which can act as pointers for further improvement of the existing numerical models.

TL;DR: A new microscopic telecentric stereo vision system is proposed to retrieve 3D data of micro-level objects by direct triangulation from two accurately calibrated telecentric cameras by using an effective searching algorithm based on the epipolar rectification of the absolute phase maps obtained from fringe projection profilometry.

TL;DR: In this paper, the authors present a system based on optical triangulation for the height monitoring, implemented on a LMD setup composed of a fiber laser, a deposition head, and an anthropomorphic robot.

TL;DR: Comparison results show that μDLP has superior performance in terms of the phase accuracy, reconstruction efficiency, and the ease of implementation over widely used Fourier-transform-based fast 3D imaging techniques, verifying that μ DLP is a powerful high-speed 3D surface imaging approach.

TL;DR: It is the first time to apply the transport of intensity equation technique to implement the optical multiple-image authentication technique and a set of numerical simulations are carried out to demonstrate the feasibility of the proposed approach.

TL;DR: A review of optical fiber Mach-Zehnder interferometers with micro-cavity fabricated by femtosecond (fs) laser was presented in this paper, where different kinds of structures of MZIs and their applications were summarized and discussed in detail.

TL;DR: A global calibration method of multi-camera system that can be completed by calibrating multiple cameras at the same time and to minimize the error of calibration, a correction method is proposed.

TL;DR: This paper describes ongoing work on the in-situ monitoring and characterization during processes of powder-fed laser-aided direct metal deposition (DMD), a form of metal AM, and the state-of-the-art with respect to an emerging field-the full-field deformation monitoring of part and/or substrate by digital image correlation (DIC).

TL;DR: The annoying silhouette problem existed in the interference-based encryption methods can be avoided effectively and a set of numerical simulations are presented to demonstrate the validity and feasibility of the proposed technique.

TL;DR: In this article, an all-fiber and compact Mach-Zehnder interferometric (MZI) sensor is proposed and experimentally demonstrated for the measurement of temperature and curvature.

TL;DR: A quaternary gray-code phase unwrapping method using only two defocused binary patterns and a weighted optimization algorithm for the design of special binary code patterns which are more expressive gray codes are presented.

TL;DR: A novel chaos-based image encryption algorithm with the orbit perturbation and dynamic state variable selection mechanisms is proposed, which provides excellent encryption performance in only one round.

TL;DR: The proposed monospectral image encryption method can directly encrypt the multispectral color information rather than having to divide into three color channels (R, G and B), thereby, the proposed method can greatly reduce the encryption calculation.

TL;DR: The Ushiki chaotic system is performed to generate the random phase mask in FrFT and a random sequence for scrambling the private key in a single optical channel system to enhance the security of the proposed cryptosystem.

TL;DR: A novel pathological image encryption scheme to ensure the transmission of a pathological image securely in a telemedicine system that is faster and more resistant to common attacks is proposed.

TL;DR: A novel steerable evidence filter is developed to generate the crack saliency map, which significantly enhances the contrast between crack and surrounding background, and a segmentation-based method including local threshold and minimum spanning tree is employed which ensures the extraction of complete crack.