International Journal of Optics https://www.hindawi.com The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. An Automatic Tree Skeleton Extracting Method Based on Point Cloud of Terrestrial Laser Scanner Wed, 18 Oct 2017 00:00:00 +0000 http://www.hindawi.com/journals/ijo/2017/5408503/ Tree skeleton could describe the shape and topological structure of a tree, which are useful to forest researchers. Terrestrial laser scanner (TLS) can scan trees with high accuracy and speed to acquire the point cloud data, which could be used to extract tree skeletons. An adaptive extracting method of tree skeleton based on the point cloud data of TLS was proposed in this paper. The point cloud data were segmented by artificial filtration and -means clustering, and the point cloud data of trunk and branches remained to extract skeleton. Then the skeleton nodes were calculated by using breadth first search (BFS) method, quantifying method, and clustering method. Based on their connectivity, the skeleton nodes were connected to generate the tree skeleton, which would be smoothed by using Laplace smoothing method. In this paper, the point cloud data of a toona tree and peach tree were used to test the proposed method and for comparing the proposed method with the shortest path method to illustrate the robustness and superiority of the method. The experimental results showed that the shape of tree skeleton extracted was consistent with the real tree, which showed the method proposed in the paper is effective and feasible. Ronghao Li, Guochao Bu, and Pei Wang Copyright © 2017 Ronghao Li et al. All rights reserved. Optical Network Models and Their Application to Software-Defined Network Management Thu, 14 Sep 2017 00:00:00 +0000 http://www.hindawi.com/journals/ijo/2017/5150219/ Software-defined networking is finding its way into optical networks. Here, it promises a simplification and unification of network management for optical networks allowing automation of operational tasks despite the highly diverse and vendor-specific commercial systems and the complexity and analog nature of optical transmission. Common abstractions and interfaces are a fundamental component for software-defined optical networking. Currently, a number of models for optical networks are available. They all claim to provide open and vendor agnostic management of optical equipment. In this work, we survey and compare the most important models and propose an intent interface for creating virtual topologies which is integrated in the existing model ecosystem. Thomas Szyrkowiec, Achim Autenrieth, and Wolfgang Kellerer Copyright © 2017 Thomas Szyrkowiec et al. All rights reserved. Resources Scheduling Algorithm in Power Wireless Private Network Based on SDON Tue, 12 Sep 2017 08:13:44 +0000 http://www.hindawi.com/journals/ijo/2017/2064638/ With the increasing of the business carried by the power wireless private network and the continuous development of the new network technology, the problems in the traditional mode of power wireless private network are becoming more and more obvious. In order to solve the problems such as poor business service quality, low system throughput, and fairness problems in the uplink resource scheduling process of power wireless private network, a dynamic uplink resource scheduling algorithm is proposed on the basis of Software Defined Optical Network (SDON). By studying the business characteristics of the uplink transmission of power wireless network, the priority of the service is evaluated before the resource scheduling is carried out. According to the characteristics of OFDM resource allocation and the numerical control separation and programmable feature of SDON, different scheduling methods are designed for different services. Simulation analysis shows that this algorithm can effectively improve the system throughput, guarantee QoS, and improve the transmission performance of different services. Ningzhe Xing Copyright © 2017 Ningzhe Xing. All rights reserved. Research on Mud Flow Rate Measurement Method Based on Continuous Doppler Ultrasonic Wave Thu, 20 Jul 2017 08:46:03 +0000 http://www.hindawi.com/journals/ijo/2017/4750290/ In deep-water drilling processes, the flow rate of drilling mud inside an annular pipe is significant judgment data for early kick detection. On the basis of the continuous-wave Doppler ultrasound, this paper proposes a new detection method of nonoriented continuous-wave Doppler ultrasound. The method solves the problem of the ultrasound having great attenuation in mud and not receiving effective signals by using a continuous ultrasound. Moreover, this method analyzes the nonoriented characteristics of ultrasound reflection on principle and proposes the detection of ultrasound Doppler frequency shift by detecting Lamb wave, which releases the detection of oil-based mud flow rate in a nonintrusive annular pipe. The feasibility of the method is verified through theoretical analysis and numerous experiments on a gas kick simulation platform. The measurement result has reached a flow accuracy approximating to the intrusive flow meter. Quan Zhou, Hui Zhao, Yufa He, Shengnan Li, Shiquan Jiang, and Huijie Zhang Copyright © 2017 Quan Zhou et al. All rights reserved. High Precision Laser Scanning of Metallic Surfaces Thu, 06 Jul 2017 10:25:47 +0000 http://www.hindawi.com/journals/ijo/2017/4134205/ Speckle noise, dynamic range of light intensity, and spurious reflections are major challenges when laser scanners are used for 3D surface acquisition. In this work, a series of image processing operations, that is, Spatial Compound Imaging, High Dynamic Range Extension, Gray Level Transformation, and Most Similar Nearest Neighbor are proposed to overcome the challenges coming from the target surface. A prototype scanner for metallic surfaces is designed to explore combinations of these image processing operations. The main goal is to find the combination of operations that will lead to the highest possible robustness and measurement precision at the lowest possible computational load. Inspection of metallic tools where the surface of its edge must be measured at micrometer precision is our test case. Precision of heights measured without using the proposed image processing is firstly analyzed to be ±7.6 μm at 68% confidence level. The best achieved height precision was ±4.2 μm. This improvement comes at 24 times longer processing time and five times longer scanning time. Dynamic range extension of the image capture improves robustness since the numbers of saturated or underexposed pixels are substantially reduced. Using a high dynamic range (HDR) camera offers a compromise between processing time, robustness, and precision. Yousaf Muhamad Amir and Benny Thörnberg Copyright © 2017 Yousaf Muhamad Amir and Benny Thörnberg. All rights reserved. Investigating Optical Properties of One-Dimensional Photonic Crystals Containing Semiconductor Quantum Wells Tue, 13 Jun 2017 00:00:00 +0000 http://www.hindawi.com/journals/ijo/2017/7280613/ This study examined MQWs made of InGaAs/GaAs, InAlAs/InP, and InGaAs/InP in terms of their band structure and reflectivity. We also demonstrated that the reflectivity of MQWs under normal incident was at maximum, while both using a strong pump and changing incident angle reduced it. Reflectivity of the structure for a weak probe pulse depends on polarization, intensity of the pump pulse, and delay between the probe pulse and the pump pulse. So this system can be used as an ultrafast all-optical switch which is inspected by the transfer matrix method. After studying the band structure of the one-dimensional photonic crystal, the optical stark effect (OSE) was considered on it. Due to the OSE on virtual exciton levels, the switching time can be in the order of picoseconds. Moreover, it is demonstrated that, by introducing errors in width of barrier and well as well as by inserting defect, the reflectivity is reduced. Thus, by employing the mechanism of stark effect MQWs band-gaps can be easily controlled which is useful in designing MWQ based optical switches and filters. By comparing the results, we observe that the reflectivity of MWQ containing 200 periods of InAlAs/InP quantum wells shows the maximum reflectivity of 96%. Mahshid Mokhtarnejad, Morteza Asgari, and Arash Sabatyan Copyright © 2017 Mahshid Mokhtarnejad et al. All rights reserved. The New Tapered Fiber Connector and the Test of Its Error Rate and Coupling Characteristics Thu, 01 Jun 2017 10:02:41 +0000 http://www.hindawi.com/journals/ijo/2017/2742709/ Since the fiber core is very small, the communication fiber connector requires high precision. In this paper, the effect of lateral deviation on coupling efficiency of fiber connector is analyzed. Then, considering the fact that optical fiber is generally used in pairs, one for transmitting data and the other for receiving, the novel directional tapered communication optical fiber connector is designed. In the new connector, the structure of the fiber head is tapered according to the signal transmission direction. In order to study the performance of the new connector, several samples were made in the laboratory of corporation CDSEI and two testing experiments were done. The experiment results show that compared with the traditional connector, for the same lateral deviation, the coupling efficiency of the tapered connector is higher and the error rate is lower. Qinggui Hu and Chengzhong Li Copyright © 2017 Qinggui Hu and Chengzhong Li. All rights reserved. Fusing Depth and Silhouette for Scanning Transparent Object with RGB-D Sensor Sun, 28 May 2017 00:00:00 +0000 http://www.hindawi.com/journals/ijo/2017/9796127/ 3D reconstruction based on structured light or laser scan has been widely used in industrial measurement, robot navigation, and virtual reality. However, most modern range sensors fail to scan transparent objects and some other special materials, of which the surface cannot reflect back the accurate depth because of the absorption and refraction of light. In this paper, we fuse the depth and silhouette information from an RGB-D sensor (Kinect v1) to recover the lost surface of transparent objects. Our system is divided into two parts. First, we utilize the zero and wrong depth led by transparent materials from multiple views to search for the 3D region which contains the transparent object. Then, based on shape from silhouette technology, we recover the 3D model by visual hull within these noisy regions. Joint Grabcut segmentation is operated on multiple color images to extract the silhouette. The initial constraint for Grabcut is automatically determined. Experiments validate that our approach can improve the 3D model of transparent object in real-world scene. Our system is time-saving, robust, and without any interactive operation throughout the process. Yijun Ji, Qing Xia, and Zhijiang Zhang Copyright © 2017 Yijun Ji et al. All rights reserved. Optical Channel Capacity Upgrade Based on Multiwavelength Conversion XGM Using Semiconductor Optical Amplifier for Access Networks Tue, 04 Apr 2017 10:12:23 +0000 http://www.hindawi.com/journals/ijo/2017/3195383/ This paper demonstrates a 10 Gb/s one-to-two-wavelength conversion configuration based on cross-gain modulation for optical access networks using a single TW-SOA. The method is capable of converting a signal data of specific wavelength 1541 nm to certain wavelengths of CW’s laser 1554 nm and 1558 nm with 4 nm spacing. The pump power level was classified due to channel response. A result obtained was the best power level offering wavelength converter between −6 and 3 dBm. The conversion efficiency achievement provided an acceptable result for probe signals. The findings of -factor performance were investigated. The values were found to be more than 9 for point to point transmission and 20 km fiber configurations for the original and converted signal. The technique implemented at 20 km and the power of all channels were adequate to provide a splitting ratio of 1/64 for the launched pump power 3 dBm. Mohammad Syuhaimi Ab-rahman and Abdul Hameed Almabrok Swedan Copyright © 2017 Mohammad Syuhaimi Ab-rahman and Abdul Hameed Almabrok Swedan. All rights reserved. Generation of Perfect Optical Vortices by Using a Transmission Liquid Crystal Spatial Light Modulator Thu, 30 Mar 2017 07:46:37 +0000 http://www.hindawi.com/journals/ijo/2017/6852019/ We have experimentally created perfect optical vortices by the Fourier transformation of holographic masks with combination of axicons and spiral functions, which are displayed on a transmission liquid crystal spatial light modulator. We showed theoretically that the size of the annular vortex in the Fourier plane is independent of the spiral phase topological charge but it is dependent on the axicon. We also studied numerically and experimentally the free space diffraction of a perfect optical vortex after the Fourier back plane and we found that the size of the intensity pattern of a perfect optical vortex depends on the topological charge and the propagation distance. Nelson Anaya Carvajal, Cristian H. Acevedo, and Yezid Torres Moreno Copyright © 2017 Nelson Anaya Carvajal et al. All rights reserved. Fourier-Domain Optical Coherence Tomography Signal Analysis and Numerical Modeling Wed, 22 Mar 2017 00:00:00 +0000 http://www.hindawi.com/journals/ijo/2017/9586067/ In this work the theory of the optical coherence tomography (OCT) signal after sampling, in dispersive media, with noise, and for a turbid medium is presented. The analytical theory is demonstrated with a one-dimensional numerical OCT model for (single) reflectors, dispersive media, and turbid media. For dispersive media the deterioration of the OCT axial resolution is quantified analytically and numerically. The OCT signal to noise ratio (SNR) is analyzed in the Fourier-domain and simulated with the numerical model. For an SNR based on the OCT intensity the conventional shot noise limited SNR is derived whereas for an SNR based on the OCT amplitude a 6.7 dB higher SNR is demonstrated. The OCT phase stability is derived in the Fourier-domain as 2SNR−1 and is validated using the numerical OCT model. The OCT single scattering model is simulated with the one-dimensional numerical model and applied to the simulation of an OCT image of a two-layered sample. J. Kalkman Copyright © 2017 J. Kalkman. All rights reserved. Hybridization State Detection of DNA-Functionalized Gold Nanoparticles Using Hyperspectral Imaging Tue, 21 Mar 2017 00:00:00 +0000 http://www.hindawi.com/journals/ijo/2017/8427459/ Hyperspectral imaging has the unique ability of capturing spectral data for multiple wavelengths at each pixel in an image. This gives the ability to distinguish, with certainty, different nanomaterials and/or distinguish nanomaterials from biological materials. In this study, 4 nm and 13 nm gold nanoparticles (Au NPs) were synthesized, functionalized with complimentary oligonucleotides, and hybridized to form large networks of NPs. Scattering spectra were collected from each sample (unfunctionalized, functionalized, and hybridized) and evaluated. The spectra showed unique peaks for each size of Au NP sample and also exhibited narrowing and intensifying of the spectra as the NPs were functionalized and then subsequently hybridized. These spectra are different from normal aggregation effects where the LSPR and reflected spectrum broaden and are red-shifted. Rather, this appears to be dependent on the ability to control the interparticle distance through oligonucleotide length, which is also investigated through the incorporation of a poly-A spacer. Also, hybridized Au NPs were exposed to cells with no adverse effects and retained their unique spectral signatures. With the ability to distinguish between hybridization states at nearly individual NP levels, this could provide a new method of tracking the intracellular actions of nanomaterials as well as extracellular biosensing applications. Richard C. Murdock, Omar A. Khan, Thomas J. Lamkin, Saber M. Hussain, and Nancy Kelley-Loughnane Copyright © 2017 Richard C. Murdock et al. All rights reserved. Microhardness, Structure, and Morphology of Primary Enamel after Phosphoric Acid, Self-Etching Adhesive, and Er:YAG Laser Etching Thu, 09 Mar 2017 08:08:55 +0000 http://www.hindawi.com/journals/ijo/2017/7634739/ Background. Phosphoric acid is the traditional etching agent; self-etching adhesives and Er:YAG laser are alternative methods. Knowledge of deciduous enamel etching is required. Aim. To evaluate primary enamel microhardness, structure, and morphology after phosphoric acid, self-etching, and Er:YAG laser etching. Design. Seventy primary incisors were assigned to five groups (): I (control), II (35% phosphoric acid), III (self-etching adhesive), IV (Er:YAG laser at 15 J/cm2), and V (Er:YAG laser at 19.1 J/cm2). Microhardness was evaluated by Vickers indentation. Chemical composition was analyzed by energy dispersive X-ray spectroscopy and morphological changes by scanning electron microscopy. One-way ANOVA, Kruskal–Wallis, Mann–Whitney , and Pearson bivariate correlation were employed (). Results. Vickers microhardness showed differences and no correlation with Ca/P ratio. Group II showed differences in carbon, oxygen, and phosphorus atomic percent and group V in Ca/P ratio. Morphological changes included exposed prisms, fractures, craters, and fusion. Conclusions. Enamel treated with phosphoric acid showed different chemical characterization among groups. Self-etching and Er:YAG laser irradiation at 19.1 J/cm2 showed similar microhardness and chemical characterization. Er:YAG laser irradiation at 15 J/cm2 maintained microhardness as untreated enamel. Er:YAG laser irradiation at 19.1 J/cm2 enhanced mineral content. Morphological retentive changes were specific to each type of etching protocol. María del Carmen Zoila Alcantara-Galeana, Rosalía Contreras-Bulnes, Laura Emma Rodríguez-Vilchis, Manuel Eduardo Espinosa-Pesqueira, Cecilia Carlota Barrera-Ortega, Itzel Monserrat López-Hurtado, and Adriana Fernández-Bobadilla Copyright © 2017 María del Carmen Zoila Alcantara-Galeana et al. All rights reserved. Impact of Radii Ratios on a Two-Dimensional Cloaking Structure and Corresponding Analysis for Practical Design at Optical Wavelengths Mon, 23 Jan 2017 12:40:19 +0000 http://www.hindawi.com/journals/ijo/2017/2541828/ This work is an extension to the evaluation and analysis of a two-dimensional cylindrical cloak in the Terahertz or visible range spectrum using Finite Difference Time-Domain (FDTD) method. It was concluded that it is possible to expand the frequency range of a cylindrical cloaking model by careful scaling of the inner and outer radius of the simulation geometry with respect to cell size and/or number of time steps in the simulation grid while maintaining appropriate stability conditions. Analysis in this study is based on a change in the radii ratio, that is, outer radius to inner radius, of the cloaking structure for an array of wavelengths in the visible spectrum. Corresponding outputs show inconsistency in the cloaking pattern with respect to frequency. The inconsistency is further increased as the radii ratio is decreased. The results also help to establish a linear relationship between the transmission coefficient and the real component of refractive index with respect to different radii ratios which may simplify the selection of the material for practical design purposes. Additional performance analysis is carried out such that the dimensions of the cloak are held constant at an average value and the frequency varied to determine how a cloaked object may be perceived by the human eye which considers different wavelengths to be superimposed on each other simultaneously. Nadia Anam and Ebad Zahir Copyright © 2017 Nadia Anam and Ebad Zahir. All rights reserved. Effect of Discrete Levels Width Error on the Optical Performance of the Diffractive Binary Lens Tue, 17 Jan 2017 09:51:56 +0000 http://www.hindawi.com/journals/ijo/2017/8730890/ The effects of discrete levels width error developed by thin film deposition on the optical performance of diffractive binary germanium lens with four discrete levels are investigated using nonsequential mode in the optical design code ZEMAX. The thin film deposition technique errors considered are metallic mask fabrication errors. The peak value of the Point Spread Function (PSF) was used as criterion to show the effect of discrete levels width error on the optical performance of the four-level binary germanium lens. Manal Alshami, Mohamed Fawaz Mousselly, and Anas Wabby Copyright © 2017 Manal Alshami et al. All rights reserved. Visible Light Communication System Using Silicon Photocell for Energy Gathering and Data Receiving Wed, 11 Jan 2017 06:34:37 +0000 http://www.hindawi.com/journals/ijo/2017/6207123/ Silicon photocell acts as the detector and energy convertor in the VLC system. The system model was set up and simulated in Matlab/Simulink environment. A 10 Hz square wave was modulated on LED and restored in voltage mode at the receiver. An energy gathering and signal detecting system was demonstrated at the baud rate of 19200, and the DC signal is about 2.77 V and AC signal is around 410 mV. Xiongbin Chen, Chengyu Min, and Junqing Guo Copyright © 2017 Xiongbin Chen et al. All rights reserved. Simultaneous Wood Defect and Species Detection with 3D Laser Scanning Scheme Mon, 19 Dec 2016 17:31:33 +0000 http://www.hindawi.com/journals/ijo/2016/7049523/ Wood grading and wood price are mainly connected with the wood defect and wood species. In this paper, a wood defect quantitative detection scheme and a wood species qualitative identification scheme are proposed simultaneously based on 3D laser scanning point cloud. First, an Artec 3D scanner is used to scan the wood surface to get the 3D point cloud. Each 3D point contains its , , and coordinate and its RGB color information. After preprocessing, the coordinate value of current point is compared with the set threshold to judge whether it is a defect point (i.e., cavity, worm tunnel, and crack). Second, a deep preferred search algorithm is used to segment the retained defect points marked with different colors. The integration algorithm is used to calculate the surface area and volume of every defect. Finally, wood species identification is performed with the wood surface’s color information. The color moments of scanned points are used for classification, but the defect points are not used. Experiments indicate that our scheme can accurately measure the surface areas and volumes of cavity, worm tunnel, and crack on wood surface with measurement error less than 5% and it can also reach a wood species recognition accuracy of 95%. Zhao Peng, Li Yue, and Ning Xiao Copyright © 2016 Zhao Peng et al. All rights reserved. A Comprehensive Lighting Configuration for Efficient Indoor Visible Light Communication Networks Thu, 08 Dec 2016 11:28:50 +0000 http://www.hindawi.com/journals/ijo/2016/8969514/ Design of an efficient indoor visible light communication (VLC) system requires careful considerations on both illumination and communication aspects. Besides fundamental factors such as received power and signal-to-noise ratio (SNR) level, studies on mobility scenarios and link switching process must be done in order to achieve good communication link quality in such systems. In this paper, a comprehensive lighting configuration for efficient indoor VLC systems for supporting mobility and link switching with constraint on illumination, received power, and SNR is proposed. Full connectivity in mobility scenarios is required to make the system more practical. However, different from other literatures, our work highlights the significance of recognizing the main influences of field of view angle on the connectivity performance in the practical indoor scenarios. A flexible link switching initiation algorithm based on the consideration of relative received power with adaptive hysteresis margin is demonstrated. In this regard, we investigate the effect of the overlap area between two light sources with respect to the point view of the receiver on the link switching performance. The simulation results show that an indoor VLC system with sufficient illumination level and high communication link quality as well as full mobility and support link switching can be achieved using our approach. Thai-Chien Bui, Suwit Kiravittaya, Keattisak Sripimanwat, and Nam-Hoang Nguyen Copyright © 2016 Thai-Chien Bui et al. All rights reserved. Observation of Dissipative Bright Soliton and Dark Soliton in an All-Normal Dispersion Fiber Laser Mon, 24 Oct 2016 06:26:46 +0000 http://www.hindawi.com/journals/ijo/2016/3946525/ This paper proposes a novel way for controlling the generation of the dissipative bright soliton and dark soliton operation of lasers. We observe the generation of dissipative bright and dark soliton in an all-normal dispersion fiber laser by employing the nonlinear polarization rotation (NPR) technique. Through adjusting the angle of the polarizer and analyzer, the mode-locked and non-mode-locked regions can be obtained in different polarization directions. Numerical simulation shows that, in an appropriate pump power range, the dissipative bright soliton and dark soliton can be generated simultaneously in the mode-locked and non-mode-locked regions, respectively. If the pump power exceeds the top limit of this range, only dissipative soliton will exist, whereas if it is below the lower bound of this range, only dark soliton will exist. Chunyang Ma, Bo Gao, Ge Wu, Tian Zhang, and Xiaojian Tian Copyright © 2016 Chunyang Ma et al. All rights reserved. Modified Three-Dimensional Multicarrier Optical Prime Codes Wed, 28 Sep 2016 13:24:54 +0000 http://www.hindawi.com/journals/ijo/2016/2683607/ We propose a mathematical model for novel three-dimensional multicarrier optical codes in terms of wavelength/time/space based on the prime sequence algorithm. The proposed model has been extensively simulated on MATLAB for prime numbers () to analyze the performance of code in terms of autocorrelation and cross-correlation. The simulated outcome resembles the mathematical model and gives better results over other methods available in the literature as far as autocorrelation and cross-correlation are concerned. The proposed 3D optical codes are more efficient in terms of cardinality, improved security, and providing quality of services. Rajesh Yadav and Gurjit Kaur Copyright © 2016 Rajesh Yadav and Gurjit Kaur. All rights reserved. Modulation Transfer Function of a Gaussian Beam Based on the Generalized Modified Atmospheric Spectrum Mon, 26 Sep 2016 06:46:34 +0000 http://www.hindawi.com/journals/ijo/2016/2613816/ This paper investigates the modulation transfer function of a Gaussian beam propagating through a horizontal path in weak-fluctuation non-Kolmogorov turbulence. Mathematical expressions are obtained based on the generalized modified atmospheric spectrum, which includes the spectral power law value of non-Kolmogorov turbulence, the finite inner and outer scales of turbulence, and other optical parameters of the Gaussian beam. The numerical results indicate that the atmospheric turbulence would produce less negative effects on the wireless optical communication system with an increase in the inner scale of turbulence. Additionally, the increased outer scale of turbulence makes a Gaussian beam influenced more seriously by the atmospheric turbulence. Chao Gao and Xiaofeng Li Copyright © 2016 Chao Gao and Xiaofeng Li. All rights reserved. Theoretical and Experimental Demonstration on Grating Lobes of Liquid Crystal Optical Phased Array Thu, 18 Aug 2016 16:32:26 +0000 http://www.hindawi.com/journals/ijo/2016/7175809/ High deflection efficiency is one of the urgent requirements for practical liquid crystal optical phased array (LC-OPA). In this paper, we demonstrate that high order grating lobes induced from fringe effect are the most important issue to reduce occupation of main lobe. A novel theoretical model is developed to analyze the feature of grating lobes when the device of LC-OPA is working on the scheme of variable period grating (VPG) or variable blazing grating (VBG). Subsequently, our experiments present the relevant results showing a good agreement with the theoretical analysis. Xiangru Wang, Liang Wu, Man Li, Shuanghong Wu, Jiyang Shang, and Qi Qiu Copyright © 2016 Xiangru Wang et al. All rights reserved. Digital Image Encryption Algorithm Design Based on Genetic Hyperchaos Wed, 20 Jul 2016 12:34:22 +0000 http://www.hindawi.com/journals/ijo/2016/2053724/ In view of the present chaotic image encryption algorithm based on scrambling (diffusion is vulnerable to choosing plaintext (ciphertext) attack in the process of pixel position scrambling), we put forward a image encryption algorithm based on genetic super chaotic system. The algorithm, by introducing clear feedback to the process of scrambling, makes the scrambling effect related to the initial chaos sequence and the clear text itself; it has realized the image features and the organic fusion of encryption algorithm. By introduction in the process of diffusion to encrypt plaintext feedback mechanism, it improves sensitivity of plaintext, algorithm selection plaintext, and ciphertext attack resistance. At the same time, it also makes full use of the characteristics of image information. Finally, experimental simulation and theoretical analysis show that our proposed algorithm can not only effectively resist plaintext (ciphertext) attack, statistical attack, and information entropy attack but also effectively improve the efficiency of image encryption, which is a relatively secure and effective way of image communication. Jian Wang Copyright © 2016 Jian Wang. All rights reserved. Multiple-Beams Splitter Based on Graphene Mon, 27 Jun 2016 10:03:14 +0000 http://www.hindawi.com/journals/ijo/2016/7651216/ Due to its tunability of conductivity, graphene can be considered as a novel epsilon-near-zero (ENZ) material. Based on this property, we propose a wave splitter using graphene. Simulation results show that the circular surface plasmon polariton waves excited by a point source can be transferred to narrow beams through a graphene-based wave splitter, which is formed by a polygonal contour of the ENZ graphene layer. The number of beams can be easily controlled by adjusting the shape of the polygonal ENZ graphene layer, and the operation frequency can also be chosen. Xiao Bing Li, Hong Ju Xu, Wei Bing Lu, and Jian Wang Copyright © 2016 Xiao Bing Li et al. All rights reserved. Components of Lens Power That Regulate Surface Principal Powers and Relative Meridians Independently Tue, 21 Jun 2016 14:21:26 +0000 http://www.hindawi.com/journals/ijo/2016/8103891/ Paraxial light rays incident in air on alternate refracting surfaces of a thick lens can yield complementary powers. This paper aims to test when these powers are invariant as surface refractive powers interchange in the expression. We solve for relevant surface powers. Potential anticommutators yield the nature of surface principal refractions along obliquely crossing perpendicular meridians; commutators yield meridians that align with those on the next surface. An invariant power component orients relative meridians or the nature of the matrix power on each noncylindrical surface demands that the other component varies. Another component of lens power aligns relative meridian positions for distinct principal powers. Interchanging surface power matrices affects this component. A symmetric lens power results if perpendicular principal meridians are associated with meridians on an opposite rotationally symmetric surface. For thin lenses, meridian alignment may be waived. An astigmatic contact lens can be specified by symmetric power despite having separated surfaces. H. Abelman and S. Abelman Copyright © 2016 H. Abelman and S. Abelman. All rights reserved. Sagnac Interferometer Based Generation of Controllable Cylindrical Vector Beams Tue, 21 Jun 2016 10:00:40 +0000 http://www.hindawi.com/journals/ijo/2016/7929813/ We report on a novel experimental geometry to generate cylindrical vector beams in a very robust manner. Continuous control of beams’ properties is obtained using an optically addressable spatial light modulator incorporated into a Sagnac interferometer. Forked computer-generated holograms allow introducing different topological charges while orthogonally polarized beams within the interferometer permit encoding the spatial distribution of polarization. We also demonstrate the generation of complex waveforms obtained by combining two orthogonal beams having both radial modulations and azimuthal dislocations. Cristian Acevedo, Angela Guzmán, Yezid Torres Moreno, and Aristide Dogariu Copyright © 2016 Cristian Acevedo et al. All rights reserved. Analytical Approach to Polarization Mode Dispersion in Linearly Spun Fiber with Birefringence Mon, 23 May 2016 08:15:35 +0000 http://www.hindawi.com/journals/ijo/2016/9753151/ The behavior of Polarization Mode Dispersion (PMD) in spun optical fiber is a topic of great interest in optical networking. Earlier work in this area has focused more on approximate or numerical solutions. In this paper we present analytical results for PMD in spun fibers with triangular spin profile function. It is found that in some parameter ranges the analytical results differ from the approximations. Vinod K. Mishra Copyright © 2016 Vinod K. Mishra. All rights reserved. Gas Bubbles Investigation in Contaminated Water Using Optical Tomography Based on Independent Component Analysis Method Mon, 16 May 2016 07:03:03 +0000 http://www.hindawi.com/journals/ijo/2016/3582649/ This paper presents the results of concentration profiles for gas bubble flow in a vertical pipeline containing contaminated water using an optical tomography system. The concentration profiles for the bubble flow quantities are investigated under five different flows conditions, a single bubble, double bubbles, 25% of air opening, 50% of air opening, and 100% of air opening flow rates where a valve is used to control the gas flow in the vertical pipeline. The system is aided by the independent component analysis (ICA) algorithm to reconstruct the concentration profiles of the liquid-gas flow. The behaviour of the gas bubbles was investigated in contaminated water in which the water sample was prepared by adding 25 mL of colour ingredients to 3 liters of pure water. The result shows that the application of ICA has enabled the system to detect the presence of gas bubbles in contaminated water. This information provides vital information on the flow inside the pipe and hence could be very significant in increasing the efficiency of the process industries. Mohd Taufiq Mohd Khairi, Sallehuddin Ibrahim, Mohd Amri Md Yunus, and Mahdi Faramarzi Copyright © 2016 Mohd Taufiq Mohd Khairi et al. All rights reserved. Differences in Nanosecond Laser Ablation and Deposition of Tungsten, Boron, and WB2/B Composite due to Optical Properties Wed, 11 May 2016 12:07:14 +0000 http://www.hindawi.com/journals/ijo/2016/5438721/ The first attempt to the deposition of WB3 films using nanosecond Nd:YAG laser demonstrated that deposited coatings are superhard. However, they have very high roughness. The deposited films consisted mainly of droplets. Therefore, in the present work, the explanation of this phenomenon is conducted. The interaction of Nd:YAG nanosecond laser pulse with tungsten, boron, and WB2/B target during ablation is investigated. The studies show the fundamental differences in ablation of those materials. The ablation of tungsten is thermal and occurs due to only evaporation. In the same conditions, during ablation of boron, the phase explosion and/or fragmentation due to recoil pressure is observed. The deposited films have a significant contribution of big debris with irregular shape. In the case of WB2/B composite, ablation is significantly different. The ablation seems to be the detonation in the liquid phase. The deposition mechanism is related mainly to the mechanical transport of the target material in the form of droplets, while the gaseous phase plays marginal role. The main origin of differences is optical properties of studied materials. A method estimating phase explosion occurrence based on material data such as critical temperature, thermal diffusivity, and optical properties is shown. Moreover, the effect of laser wavelength on the ablation process and the quality of the deposited films is discussed. Tomasz Moscicki Copyright © 2016 Tomasz Moscicki. All rights reserved. Center Symmetric Local Multilevel Pattern Based Descriptor and Its Application in Image Matching Wed, 11 May 2016 11:49:05 +0000 http://www.hindawi.com/journals/ijo/2016/1584514/ This paper presents an effective local image region description method, called CS-LMP (Center Symmetric Local Multilevel Pattern) descriptor, and its application in image matching. The CS-LMP operator has no exponential computations, so the CS-LMP descriptor can encode the differences of the local intensity values using multiply quantization levels without increasing the dimension of the descriptor. Compared with the binary/ternary pattern based descriptors, the CS-LMP descriptor has better descriptive ability and computational efficiency. Extensive image matching experimental results testified the effectiveness of the proposed CS-LMP descriptor compared with other existing state-of-the-art descriptors. Hui Zeng, Xiuqing Wang, and Yu Gu Copyright © 2016 Hui Zeng et al. All rights reserved.