- 标题
- 摘要
- 关键词
- 实验方案
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Lorentzian demodulation algorithm for multimode polymer optical fiber Bragg gratings
摘要： For strain sensing applications, we develop a simple and accurate Lorentzian demodulation algorithm for fiber Bragg gratings (FBGs) inscribed in multimode optical fibers. As multimode FBG spectra generally exhibit multiple peaks, simply tracking some particular spectral peaks (i.e., maximum detection) results in measurement failure when the strain is large. Here, using an FBG inscribed in a perfluorinated graded-index multimode polymer optical fiber, we experimentally evaluate the new method by comparing its performance with those of other demodulation algorithms, such as the maximum and centroid detection methods. Finally, using this method, we demonstrate the accurate measurement of strain of up to 1.0%.
关键词： fiber Bragg gratings,FBG,Lorentzian demodulation algorithm,strain sensing,multimode polymer optical fiber Bragg gratings
更新于2025-11-28 14:24:03
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Complex Inverse Design of Meta-optics by Segmented Hierarchical Evolutionary Algorithm
摘要： With the recent burgeoning advances in nano-optics, ultracompact, miniaturized photonic devices with high-quality and spectacular functionalities are highly desired. Such devices’ design paradigms often call for the solution of a complex inverse nonanalytical/semianalytical problem. However, currently reported strategies dealing with amplitude-controlled meta-optics devices achieved limited functionalities mainly due to restricted search space and demanding computational schemes. Here, we established a segmented hierarchical evolutionary algorithm, aiming to solve large-pixelated, complex inverse meta-optics design and fully demonstrate the targeted performance. This paradigm allows significantly extended search space at a rapid converging speed. As typical complex proof-of-concept examples, large-pixelated meta-holograms are chosen to demonstrate the validity of our design paradigm. An improved fitness function is proposed to reinforce the performance balance among image pixels, so that the image quality is improved and computing speed is further accelerated. Broadband and full-color meta-holograms with high image fidelities using binary amplitude control are demonstrated experimentally. Our work may find important applications in the advanced design of future nanoscale high-quality optical devices.
关键词： full-color meta-holograms,fast-converging algorithm,meta-optics,segmented hierarchical evolutionary algorithm,complex large-pixelated inverse design
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE SmartWorld, Ubiquitous Intelligence & Computing, Advanced & Trusted Computing, Scalable Computing & Communications, Cloud & Big Data Computing, Internet of People and Smart City Innovation (SmartWorld/SCALCOM/UIC/ATC/CBDCom/IOP/SCI) - Guangzhou, China (2018.10.8-2018.10.12)] 2018 IEEE SmartWorld, Ubiquitous Intelligence & Computing, Advanced & Trusted Computing, Scalable Computing & Communications, Cloud & Big Data Computing, Internet of People and Smart City Innovation (SmartWorld/SCALCOM/UIC/ATC/CBDCom/IOP/SCI) - An Efficient Recognition Method for Incomplete Iris Image Based on CNN Model
摘要： The iris of the eye is a research hot spot in the field of biometric identification because of its uniqueness, non-contact and bioactivity. The incompleteness of the iris caused by the acquisition process has brought great uncertainty to the subsequent iris region segmentation and iris code matching, thereby reducing the efficiency of iris recognition. This paper describes a deep convolution neural network model with adaptive incomplete iris preprocessing mechanism. Based on the normalization of the iris image, the incomplete iris preprocessing mechanism adopts the method of making the inner circle or the outer circle. The iris region can be segmented by the line fitting and the circle fitting method for extracting as many iris features as possible. The deep convolution neural network then uses pixel coding of Irregular iris regions to complete the iris pattern classification. The model fully utilizes the characteristics of deep learning, local feature characterization and weight sharing, and realizes the problem of using large sample to compensate the incomplete feature of local feature. The experimental results show that this method has significant accuracy improvement compared with the traditional algorithms.
关键词： iris recognition,convolution neural network,iris image normalization,algorithm
更新于2025-09-23 15:23:52
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Detection of Knot Defects on Coniferous Wood Surface Using Near Infrared Spectroscopy and Chemometrics
摘要： Lumber pieces usually contain defects such as knots, which strongly affect the strength and stiffness. To develop a model for rapid, accurate grading of lumbers based on knots, Douglas fir, spruce-pine-fir (SPF), Chinese hemlock, and Dragon spruce were used. The experiments explored the effects of modelling methods and spectral preprocess methods for knot detection, and investigated the feasibility of using a model built within one species to discriminate the samples from other species, using a novel variable selection method-random frog to select effective wavelengths. The results showed that least squares-support vector machines coupled with first derivative preprocessed spectra achieved best performance for both single and mixed models. Models built within Dragon spruce could be used to classify knot samples from SPF and Chinese hemlock but not Douglas fir, and vice versa. Eight effective wavelengths (1314 nm, 1358 nm, 1409 nm, 1340 nm, 1260 nm, 1586 nm, 1288 nm, and 1402 nm) were selected by RF to build effective wavelengths based models. The sensitivity, specificity, and accuracy in the validation set were 98.49%, 93.42%, and 96.30%, respectively. Good results could be obtained when using data at just eight wavelengths, as an alternative to evaluating the whole spectrum.
关键词： Coniferous wood,Knot detection,Near infrared spectroscopy (NIRS),Random frog algorithm,Least squares-support vector machines (LS-SVM)
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Conference on Computer and Communication Engineering Technology (CCET) - Beijing, China (2018.8.18-2018.8.20)] 2018 IEEE International Conference on Computer and Communication Engineering Technology (CCET) - Elastic Optical Network Spectrum Fragmentation Algorithm
摘要： Aiming at spectrum allocation problem in elastic optical networks, a spectrum allocation method that combines the advantages of genetic algorithm and ant colony algorithm is proposed. This method uses genetic algorithm to generate the initial solution with rapid random population global search ability. Then the initial solution of the genetic algorithm is transformed into the initial distribution of pheromone required by the ant colony algorithm using the cohesion strategy. Finally, the positive feedback and efficient convergence of the ant colony algorithm are used. Features Find the optimal solution and provide a solution for improving network efficiency
关键词： Network Spectrum,Elastic Optical Network,Fragmentation Algorithm
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Power, Energy, Control and Transmission Systems (ICPECTS) - Chennai (2018.2.22-2018.2.23)] 2018 International Conference on Power, Energy, Control and Transmission Systems (ICPECTS) - Design and Hardware Implementation of Self Lift Negative Output Luo Converter Using MPPT for PV Applications
摘要： The design and analysis of self lift N/O luo converter is discussed in this paper. The incremental conductance mppt extracts the maximum power from PV panel and transfers to the load. The PV panel is designed by using equivalent circuit of PV cell. The output obtained from the solar panel contains more ripples. The ripples will produce more fluctuations. By using self lift negative output luo converter the unregulated output will be conveted into regulated voltage and stepped up to the higher voltage. For obtaining simulation results Matlab software is used.
关键词： Incremental conductance (IncCond) Maximum Power Point Tracking (MPPT) algorithm,self lift negative output luo converter,Photovoltaic system
更新于2025-09-23 15:23:52
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Enhancement of objects in photoacoustic tomography using selective filtering
摘要： Here we developed a real-time photoacoustic tomography (PAT) imaging acquisition device based on the linear array transducer utilized on ultrasonic devices. Also, we produced a phantom including diverse contrast media and acquired PAT imaging as the light source wavelength was changing to see if the contrast media reacted. Indocyanine green showed the highest reaction around the 800-nm band, methylene blue demonstrated the same in the 750-nm band, and gold nanoparticle showed the same in the 700-nm band. However, in the case of superparamagnetic iron oxide, we observed not reaction within the wavelength bands used herein to obtain imaging. Moreover, we applied selective filtering to the acquired PAT imaging to remove noise from around and reinforce the object’s area. Consequentially, we could see the object area in the imaging was effectively detected and the image noise was removed.
关键词： Photoacoustic image,real-time,back projection algorithm,selective filtering,ultrasonic imaging
更新于2025-09-23 15:23:52
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Two-Dimensional Imaging Based on Near-Field Focused Array Antenna
摘要： In this letter, a near-field focused array antenna is applied to two-dimensional (2-D) microwave imaging, which steers its focus on the designed focal plane by changing the operating frequency and by phase control in two directions, respectively. The imaging system is composed of this array and two microstrip antennas, as receiver and transmitters, respectively. Simulations and measurements have proved the feasibility of the image reconstruction approach. The proposed method has a high imaging speed due to fast electrical beam scan, and thanks to the frequency scan performance of the array in one dimension, it also shows low-cost property against the fully phased method.
关键词： near-field focused beams,Microwave imaging,phased arrays,reconstruction algorithm
更新于2025-09-23 15:23:52
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Experimental verification of turbidity tolerance of stereo-vision-based 3D pose estimation system
摘要： This paper presents the verification of the turbidity tolerance of a stereo-vision-based 3D pose estimation system for underwater docking applications. To the best of the authors’ knowledge, no studies have yet been conducted on 3D pose (position and orientation) estimation against turbidity for underwater vehicles. Therefore, the effect of turbidity on the 3D pose estimation performance of underwater vehicles and a method of operating under turbid conditions were studied in this work. A 3D pose estimation method using the real-time multi-step genetic algorithm (RM-GA) proposed by the authors in the previous works shows robust pose estimation performance against changing environmental conditions. This paper discusses how and why the RM-GA is well suited to effective 3D pose estimation, even when turbid conditions disturb visual servoing. The experimental results confirm the performance of the proposed 3D pose estimation system under different levels of turbidity. To demonstrate the practical usefulness of the RM-GA, docking experiments were conducted in a turbid pool and a real sea environment to verify the performance and tolerance of the proposed system under turbid conditions. The experimental results verify the robustness of the system against turbidity, presenting a possible solution to a major problem in the field of robotics.
关键词： Robustness against turbidity,Real-time multi-step genetic algorithm,Sea docking,3D pose estimation,Stereo-vision,Visual servoing
更新于2025-09-23 15:23:52
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Influence of Heart Rate and Innovative Motion-Correction Algorithm on Coronary Artery Image Quality and Measurement Accuracy Using 256-Detector Row Computed Tomography Scanner: Phantom Study
摘要： Objective: To investigate the efficacy of motion-correction algorithm (MCA) in improving coronary artery image quality and measurement accuracy using an anthropomorphic dynamic heart phantom and 256-detector row computed tomography (CT) scanner. Materials and Methods: An anthropomorphic dynamic heart phantom was scanned under a static condition and under heart rate (HR) simulation of 50–120 beats per minute (bpm), and the obtained images were reconstructed using conventional algorithm (CA) and MCA. We compared the subjective image quality of coronary arteries using a four-point scale (1, excellent; 2, good; 3, fair; 4, poor) and measurement accuracy using measurement errors of the minimal luminal diameter (MLD) and minimal luminal area (MLA). Results: Compared with CA, MCA significantly improved the subjective image quality at HRs of 110 bpm (1.3 ± 0.3 vs. 1.9 ± 0.8, p = 0.003) and 120 bpm (1.7 ± 0.7 vs. 2.3 ± 0.6, p = 0.006). The measurement error of MLD significantly decreased on using MCA at 110 bpm (11.7 ± 5.9% vs. 18.4 ± 9.4%, p = 0.013) and 120 bpm (10.0 ± 7.3% vs. 25.0 ± 16.5%, p = 0.013). The measurement error of the MLA was also reduced using MCA at 110 bpm (19.2 ± 28.1% vs. 26.4 ± 21.6%, p = 0.028) and 120 bpm (17.9 ± 17.7% vs. 34.8 ± 19.6%, p = 0.018). Conclusion: Motion-correction algorithm can improve the coronary artery image quality and measurement accuracy at a high HR using an anthropomorphic dynamic heart phantom and 256-detector row CT scanner.
关键词： Heart rate,Tomography,X-ray computed,Coronary vessels,Phantoms,Imaging,Motion-correction algorithm
更新于2025-09-23 15:23:52