- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[OSA CLEO: Science and Innovations - San Jose, California (2015..-..)] CLEO: 2015 - Demonstration of Distance Emulation for an Orbital-Angular-Momentum Beam
摘要： We design and experimentally demonstrate a free-space distance emulator for propagating OAM beams over long distances in a lab environment. The performance of the system is assessed by measuring spot radius and radius of curvature of propagated beams.
关键词： OAM beams,Orbital-angular-momentum,free-space emulator,Laguerre Gaussian beams
更新于2025-09-09 09:28:46
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Generation of breathing solitons in the propagation and interactions of Airy–Gaussian beams in a cubic–quintic nonlinear medium
摘要： Using the split-step Fourier transform method, we numerically investigate the generation of breathing solitons in the propagation and interactions of Airy–Gaussian (AiG) beams in a cubic–quintic nonlinear medium in one transverse dimension. We show that the propagation of single AiG beams can generate stable breathing solitons that do not accelerate within a certain initial power range. The propagation direction of these breathing solitons can be controlled by introducing a launch angle to the incident AiG beams. When two AiG beams accelerated in opposite directions interact with each other, different breathing solitons and soliton pairs are observed by adjusting the phase shift, the beam interval, the amplitudes, and the light ?eld distribution of the initial AiG beams.
关键词： Airy–Gaussian beams,breathing solitons,propagation and interactions,cubic–quintic nonlinear medium
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Chongqing (2018.6.27-2018.6.29)] 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Multi-Focus Image Fusion Using Block-Wise Color-Principal Component Analysis
摘要： In this work, multi-focus image fusion method has been proposed by using color-principal component analysis (C-PCA). Proposed method consists of different phases. In the first phase, both source images have been converted into three RGB color channels. In the next phase, for each channel, covariance’s has been calculated for both images. Special weights have been calculated to generate intermediate images. In the next phase, Convolution has been used with Gaussian blur to make image smooth. Zero-crossing based second order-derivative has been incorporated to calculate edges. In the last phase, images have been decomposed into blocks. Salient features information by using Laplacian of Gaussian and Spatial Frequency of each block have been used to get the fused image. Experimental results show that the proposed method performs well as compare to existing methods by using quality matrices.
关键词： spatial frequency,multi-focus image fusion,laplacian of Gaussian,principal component analysis
更新于2025-09-09 09:28:46
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[IEEE 2018 International Seminar on Application for Technology of Information and Communication (iSemantic) - Semarang, Indonesia (2018.9.21-2018.9.22)] 2018 International Seminar on Application for Technology of Information and Communication - Improved Edge Detection Based on Adaptive Gaussian Smoothing in X-Ray Image
摘要： Currently technological developments are needed in all aspects of human life. It also covers the provision of data or information because it is related to someone's life. Data or information that provided in image formats is developed in health field of a human's life because it contains a lot of information about patient health that can’t be described by text or audio format. Currently due to the human body is susceptible to radiation rays then as long as the patient is detected by x-ray it will be subjected to a process of radiation exposure so that the x-ray image results in a decrease (degradation) of quality. There are several operations used in image processing to solve that problem. One of them is an edge detection. Due to the current edge detection is still considered not perfect because there is still Gaussian noise. So in this paper proposed method to improve image quality from quantum noise disorder by improving the method of Sobel, so can help the medical world in detecting a disease.
关键词： quality degradation,Sobel method,Gaussian noise,radiation exposure,edge detection
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Comparing Different Preprocessing Methods in Automated Segmentation of Retinal Vasculature
摘要： Computer methods and image processing provide medical doctors assistance at any time and relieve their work load, especially for iterative processes like identifying objects of interest such as lesions and anatomical structures from the image. Vescular detection is considered to be a crucial step in some retinal image analysis algorithms to find other retinal landmarks and lesions, and their corresponding diameters, to use as a length reference to measure objects in the retina. The objective of this study is to compare effect of two preprocessing methods on retinal vessel segmentation methods, Laplacian-of-Gaussian edge detector (using second-order spatial differentiation), Canny edge detector (estimating the gradient intensity), and Matched filter edge detector either in the normal fundus images or in the presence of retinal lesions like diabetic retinopathy. The steps for the segmentation are as following: 1) Smoothing: suppress as much noise as possible, without destroying the true edges, 2) Enhancement: apply a filter to enhance the quality of the edges in the image (sharpening), 3) Detection: determine which edge pixels should be discarded as noise and which should be retained by thresholding the edge strength and edge size, 4) Localization: determine the exact location of an edge by edge thinning or linking. From the accuracy view point, comparing to manual segmentation performed by ophthalmologists for retinal images belonging to a test set of 120 images, by using first preprocessing method, Illumination equalization, and contrast enhancement , the accuracy of Canny, Laplacian-of-Gaussian, and Match filter vessel segmentation was more than 85% for all databases (MUMS-DB, DRIVE, MESSIDOR). The performance of the segmentation methods using top-hat preprocessing (the second method) was more than 80%. And lastly, using matched filter had maximum accuracy for the vessel segmentation for all preprocessing steps for all databases.
关键词： contrast Enhancement,image processing,Diabetic retinopathy,top hat transformation,Laplacian-of-Gaussian edge detector,Illumination Equalization,retinal blood vessel,Match filter,Canny edge detector
更新于2025-09-09 09:28:46
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Revolution and spin of a particle induced by an orbital-angular-momentum-carrying Laguerre-Gaussian beam in a dielectric chiral medium
摘要： We reveal an interesting phenomenon of the acceleration and deceleration of the phase rotation for an orbital-angular-momentum-carrying Laguerre-Gaussian beam in a chiral medium. Under this circumstance, the differences between the optical force and optical torque exerted on a dielectric spherical particle for chiral and achiral cases are demonstrated. The optical force and torque are exerted on the particle simultaneously, which makes the particle revolve and spin simultaneously, as a planet in the solar system. We hope the results may point to a unique routine of optical manipulation.
关键词： optical manipulation,chiral medium,optical torque,Laguerre-Gaussian beam,optical force
更新于2025-09-09 09:28:46
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Wave Propagation Concepts for Near-Future Telecommunication Systems || Light Wave Propagation and Scattering Through Particles
摘要： The study of light propagating and scattering for various particles has always been important in many practical applications, such as optical diagnostics for combustion, monitoring of atmospheric pollution, analysis of the structure and pathological changes of the biological cell, laser Doppler technology, and so on. This chapter discusses propagation and scattering through particles. The description of the solution methods, numerical results, and potential application of the light scattering by typical particles is introduced. The generalized Lorenz-Mie theory (GLMT) for solving the problem of Gaussian laser beam scattering by typical particles with regular shapes, including spherical particles, spheroidal particles, and cylindrical particles, is described. The numerical methods for the scattering of Gaussian laser beam by complex particles with arbitrarily shape and structure, as well as random discrete particles are introduced. The essential formulations of numerical methods are outlined, and the numerical results for some complex particles are also presented.
关键词： Gaussian laser beam,generalized Loren-Mie theory,light scattering,numerical method,small particles
更新于2025-09-09 09:28:46
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Modulation Mode Detection & Classification for in-Vivo Nano-Scale Communication Systems Operating in Terahertz Band
摘要： This work initiates the efforts to design an intelligent/cognitive nano receiver operating in Terahertz (THz) band. Specifically, we investigate two essential ingredients of an intelligent nano receiver—modulation mode detection (to differentiate between pulse based modulation and carrier based modulation), and modulation classification (to identify the exact modulation scheme in use). To implement modulation mode detection, we construct a binary hypothesis test in nano-receiver’s passband, and provide closed-form expressions for the two error probabilities. As for modulation classification, we aim to represent the received signal of interest by a Gaussian mixture model (GMM). This necessitates the explicit estimation of the THz channel impulse response, and its subsequent compensation (via deconvolution). We then learn the GMM parameters via Expectation-Maximization algorithm. We then do Gaussian approximation of each mixture density to compute symmetric Kullback-Leibler divergence in order to differentiate between various modulation schemes (i.e., M -ary phase shift keying, M -ary quadrature amplitude modulation). The simulation results on mode detection indicate that there exists a unique Pareto-optimal point (for both SNR and the decision threshold) where both error probabilities are minimized. The main takeaway message by the simulation results on modulation classification is that for a pre-specified probability of correct classification, higher SNR is required to correctly identify a higher order modulation scheme. On a broader note, this work should trigger the interest of the community in the design of intelligent/cognitive nano receivers (capable of performing various intelligent tasks, e.g., modulation prediction etc.).
关键词： nano-scale communication,Expectation-Maximization algorithm,Kullback-Leibler divergence,Gaussian mixture model (GMM),modulation classification,Terahertz (THz) band,modulation mode detection
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Automated Optic Nerve Head Detection Based on Different Retinal Vasculature Segmentation Methods and Mathematical Morphology
摘要： Computer vision and image processing techniques provide important assistance to physicians and relieve their work load in different tasks. In particular, identifying objects of interest such as lesions and anatomical structures from the image is a challenging and iterative process that can be done by using computer vision and image processing approaches in a successful manner. Optic Nerve Head (ONH) detection is a crucial step in retinal image analysis algorithms. The goal of ONH detection is to ?nd and detect other retinal landmarks and lesions and their corresponding diameters, to use as a length reference to measure objects in the retina. The objective of this study is to apply three retinal vessel segmentation methods, Laplacian-of-Gaussian edge detector, Canny edge detector, and Matched ?lter edge detector for detection of the ONH either in the normal fundus images or in the presence of retinal lesions (e.g. diabetic retinopathy). The steps for the segmentation are as following: 1) Smoothing: suppress as much noise as possible, without destroying the true edges, 2) Enhancement: apply a ?lter to enhance the quality of the edges in the image (sharpening), 3) Detection: determine which edge pixels should be discarded as noise and which should be retained by thresholding the edge strength and edge size, 4) Localization: determine the exact location of an edge by edge thinning or linking. To evaluate the accuracy of our proposed method, we compare the output of our proposed method with the ground truth data that collected by ophthalmologists on retinal images belonging to a test set of 120 images. As shown in the results section, by using the Laplacian-of-Gaussian vessel segmentation, our automated algorithm ?nds 18 ONHs in true location for 20 color images in the CHASE-DB database and all images in the DRIVE database. For the Canny vessel segmentation, our automated algorithm ?nds 16 ONHs in true location for 20 images in the CHASE-DB database and 32 out of 40 images in the DRIVE database. And lastly, using matched ?lter in the vessel segmentation, our algorithm ?nds 19 ONHs in true location for 20 images in CHASE-DB database and all images in the DRIVE.
关键词： Laplacian-of-Gaussian edge detector,Diabetic retinopathy,Match ?lter,image processing,Optic Nerve Head,Canny edge detector,retinal blood vessel
更新于2025-09-09 09:28:46
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Focus Assessment Method of Gaze Tracking Camera Based on ε-Support Vector Regression
摘要： In order to capture an eye image of high quality in a gaze-tracking camera, an auto-focusing mechanism is used, which requires accurate focus assessment. Although there has been previous research on focus assessment in the spatial or wavelet domains, there are few previous studies that combine all of the methods of spatial and wavelet domains. Since all of the previous focus assessments in the spatial or wavelet domain methods have disadvantages, such as being affected by illumination variation, etc., we propose a new focus assessment method by combining the spatial and wavelet domain methods for the gaze-tracking camera. This research is novel in the following three ways, in comparison with the previous methods. First, the proposed focus assessment method combines the advantages of spatial and wavelet domain methods by using ε-support vector regression (SVR) with a symmetrical Gaussian radial basis function (RBF) kernel. In order to prevent the focus score from being affected by a change in image brightness, both linear and nonlinear normalizations are adopted in the focus score calculation. Second, based on the camera optics, we mathematically prove the reason for the increase in the focus score in the case of daytime images or a brighter illuminator compared to nighttime images or a darker illuminator. Third, we propose a new criterion to compare the accuracies of the focus measurement methods. This criterion is based on the ratio of relative overlapping amount (standard deviation of focus score) between two adjacent positions along the Z-axis to the entire range of focus score variety between these two points. Experimental results showed that the proposed method outperforms other methods.
关键词： ε-support vector regression with a symmetrical Gaussian radial basis function kernel,auto-focusing,focus assessment,camera optics,gaze-tracking camera
更新于2025-09-09 09:28:46