- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Noise reduction and retrieval by modified lidar inversion method combines joint retrieval method and machine learning
摘要： To address the problem in which the signal-to-noise ratio of a raw atmospheric lidar signal decreases rapidly as the range increases, which has a tremendous effect on the accuracy and the effective range of lidar retrieval, many de-noising algorithms have been proposed. Among these methods, those based on the ensemble Kalman Filter (EnKF) exhibit good performance. EnKF-based methods can simultaneously denoise lidar signals and yield accurate retrieval results. However, due to poor forecasting in the EnKF step, biases exist in the results of these methods. In this study, a modified lidar inversion method was proposed for horizontal aerosol characteristic retrieval, which combines the joint retrieval method and Gaussian processing machine learning. This method compensates for the poor forecasting in the EnKF step in the joint retrieval method through the Gaussian processing machine learning algorithm, which can reduce the biases in the retrieval results. The modified lidar inversion method was applied to both simulated and real lidar signals, and the results show that the modified lidar inversion method is effective and practical in aerosol extinction characteristics’ analysis.
关键词： lidar,Gaussian processing machine learning,ensemble Kalman Filter,signal-to-noise ratio,aerosol extinction characteristics
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Conference on System, Computation, Automation and Networking (ICSCAN) - Pondicherry, India (2018.7.6-2018.7.7)] 2018 IEEE International Conference on System, Computation, Automation and Networking (ICSCA) - Robust RGB Image Thresholding with Shannon’s Entropy and Jaya Algorithm
摘要： Image thresholding is a common pre-processing procedure implemented in various domains to improve the picture quality. In this work, thresholding of benchmark RGB- scale picture is implemented with the Jaya Algorithm (JA) and Shannon’s Entropy (SE). The investigational work is executed using Matlab7 software on RGB pictures of varied sizes. This work examines the original and the noise stained pictures based on the chosen threshold. In order to assess the performance of JA+SE, Picture-Quality-Measures (PQM) are computed by comparing the original and thresholded pictures. The average outcome confirms that, JA+SE provide better PQM values in both the normal and noise corrupted cases. Hence, this study confirms that, pre-processing with SE helps to attain better values of the error and PSNR values for the considered images of different size and quality.
关键词： Shannon’s Entropy,Gaussian-Noise,Examination.,Thresholding,RGB image
更新于2025-09-10 09:29:36
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High Precision Position Measurement Method for Laguerre-Gaussian Beams Using a Quadrant Detector
摘要： In this paper, we propose a new method to improve the position measurement accuracy for Laguerre-Gaussian beams on a quadrant detector (QD). First, the error effects of the detector diameter and the gap size are taken into account, and the position error compensation factor is introduced into the conventional formula. Then, in order to reduce the number of parameters, the concept of effective radius is proposed. Thus, a new analytical expression is obtained with a best fit using the least square method. It is verified by simulation that this approach can reduce the maximum error by 97.4% when the beam radius is 0.95 mm; meanwhile, the root mean square errors under different radii are all less than 0.004 mm. The results of simulation show that the new method could effectively improve the accuracy of the QD measurement for different radii. Therefore, the new method would have a good prospect in the engineering practice of beam position measurements.
关键词： quadrant detector,detection,Laguerre-Gaussian beams,effective radius,position measurement method,least square method
更新于2025-09-10 09:29:36
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Twisted beam shaping by plasma photonic crystal
摘要： In this paper, we investigate the strong modification and reshaping of the Laguerre-Gaussian (LG) beam using a tailored magnetized plasma photonic crystal (PPC), based on the angular spectrum expansion and 4 × 4 matrix method. It is numerically shown that by manipulating both external magnetic field and plasma number density, the reflected and transmitted beam shape is perfectly controlled. In addition, to show the domain role of magnetized PPC birefringence in the shaping of the twisted beam (TB), vertical incidence and oblique incidence of the LG beam are analyzed. We believe that these results open the door to use PPC structures in modulating the shape of a reference TB for new optical traps. Meanwhile, this study gives a new insight into the diagnostic of plasma systems using analyses of TB shapes.
关键词： plasma photonic crystal,optical traps,Laguerre-Gaussian beam,plasma diagnostics,twisted beam
更新于2025-09-10 09:29:36
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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) - The Behavior Understanding of Moving Objects Based on Vision
摘要： The moving detection and understanding are two important parts of intelligent monitoring. Firstly, the initial background was created by mean algorithm, then the Self Adapted Background Subtraction Algorithm was used to detect the moving object, and the Gaussian Hermite Moment, the centroid and area feature were extracted, and the tracking algorithm of moving object was developed with the help of these features. The classification of moving object was realized with the help of the feature and the Adaptive Resonance Theory (ART). Finally, we can understand the behavior of moving objects based on the warning line, understand the moving objects based on ART, and understand the behavior of moving objects based on trajectories. The experiment shows that the algorithm was effective.
关键词： Gaussian Hermite moments,detection of moving objects,tracking of moving objects,behavior understanding
更新于2025-09-10 09:29:36
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Simulation of Gaussian channels via teleportation and error correction of Gaussian states
摘要： Gaussian channels are the typical way to model the decoherence introduced by the environment in continuous-variable quantum states. It is known that those channels can be simulated by a teleportation protocol using as a resource state either a maximally entangled state passing through the same channel, i.e., the Choi state, or a state that is entangled at least as much as the Choi state. Since the construction of the Choi state requires infinite mean energy and entanglement, i.e., it is unphysical, we derive instead every physical state able to simulate a given channel through teleportation with finite resources and we further find the optimal ones, i.e., the resource states that require the minimum energy and entanglement. We show that the optimal resource states are pure and equally entangled to the Choi state as measured by the entanglement of formation. We also show that the same amount of entanglement is enough to simulate an equally decohering channel, while even more entanglement can simulate less decohering channels. We finally use that fact to generalize a previously known error-correction protocol by making it able to correct noise coming not only from pure loss but from thermal loss channels as well.
关键词： Gaussian states,quantum teleportation,error correction,Gaussian channels,entanglement of formation
更新于2025-09-09 09:28:46
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Nonadiabatic transition probabilities in a time-dependent Gaussian pulse or plateau pulse: Toward experimental tests of the differences from Dirac’s transition probabilities
摘要： For a quantum system subject to a time-dependent perturbing field, Dirac’s analysis gives the probability of transition to an excited state |k? in terms of the norm square of the entire excited-state coefficient ck(t) in the wave function. By integrating by parts in Dirac’s equation for ck(t) at first order, Landau and Lifshitz separated ck(t) into an adiabatic term ak(t) that characterizes the gradual adjustment of the ground state to the perturbation without transitions and a nonadiabatic term bk(t) that depends explicitly on the time derivative of the perturbation at times t′ ≤ t. Landau and Lifshitz stated that the probability of transition in a pulsed perturbation is given by |bk(t)|2, rather than by |ck(t)|2. We use the term “transition probability” to refer to the probability that a true excited-state component is present in the time-evolved wave function, as opposed to a smooth modification of the initial state. In recent work, we have examined the differences between |bk(t)|2 and |ck(t)|2 when a system is perturbed by a harmonic wave in a Gaussian envelope. We showed that significant differences exist when the frequency of the harmonic wave is off-resonance with the transition frequency. In this paper, we consider Gaussian perturbations and pulses that rise via a half Gaussian shoulder to a level plateau and later return to zero via a down-going half Gaussian. While the perturbation is constant, the transition probability |bk(t)|2 does not change. By contrast, |ck(t)|2 continues to oscillate while the perturbation is constant, and its time averaged value differs from |bk(t)|2. We suggest a general type of experiment to prove that the transition probability is given by |bk(t)|2, not |ck(t)|2. We propose a ratio test that does not require accurate knowledge of transition matrix elements or absolute field intensities.
关键词： time-dependent Gaussian pulse,Nonadiabatic transition probabilities,experimental tests,Dirac’s transition probabilities,plateau pulse
更新于2025-09-09 09:28:46
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The effect of the geometrical optical phase on the propagation of Hermite-Gaussian beams through transversal and parallel dielectric blocks
摘要： When an optical beam propagates through dielectric blocks, its optical phase is responsible for the path of the beam. In particular, the first order Taylor expansion of the geometrical part reproduces the path predicted by the Snell and reflection laws whereas the first order expansion of the Fresnel phase leads to the Goos-H?nchen shift. In this paper, we analyze the effects of the second order Taylor expansion of the geometrical phase on the shape of the optical beam and show how it affects the transversal symmetry of Hermite-Gaussian beams. From the analytical expression of the transmitted beam, it is possible to determine in which transversal and parallel dielectric blocks configuration the transversal symmetry breaking is maximized or when the symmetry is recovered. We also discuss the axial spreading delay.
关键词： spreading delay,Hermite-Gaussian beams,Optical phase,transversal symmetry breaking
更新于2025-09-09 09:28:46
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Energy-exergy modeling of solar radiation with most influencing input parameters
摘要： In this study, a new soft computing model Gaussian process regression (GPR) was evaluated for modeling the total solar radiation (TSR) and exergy (Ф) in Hakkari province (the region with the highest sunshine duration), Turkey. For this purpose, meteorological data include average, maximum and minimum temperature (Tave, Tmax, Tmin), relative humidity (H), sea level pressure (P), wind speed (W), and total sunbathing time (TST), wihch were used, and sensitivity analysis was applied for evaluating the results of TSR and Ф modeling. The results showed that all the input variables have significant impact on TSR and Ф modeling. Mean absolute percentage error and coefficient of determination (R2) for TSR and Ф predicted by GPR were 1.51–7.02% and 0.97–0.95, respectively. Application of five-fold cross validation method showed that GPR model is able to predict the TSR and Ф with a small size of data, but for more accuracy, it is suggested to use more than 70% of total data set for training the models. This research showed that GPR has a good ability for modeling the TSR and Ф with high accuracy, and so the engineers can use this method for the TSR and Ф prediction without using the solar radiation or exergy-to-energy ratio.
关键词： solar energy,Solar radiation exergy,Hakkari province of Turkey,Gaussian process regression (GPR),modeling
更新于2025-09-09 09:28:46
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Optical Tomograms of Multiple-Photon-Added Gaussian States via the Intermediate State Representation Theory
摘要： Optical tomogram of a quantum state can serve as an alternative to its density matrix since it contains all the information on this state. In this paper we use the explicit expression of the intermediate state |q, f, g? (that is, an eigenvector of the coordinate and momentum operator fQ + gP) and the Radon transform between the Wigner operator Δ (p, q) and the pure-state density operator |q, f, g? ?q, f, g| to calculate the specific tomograms for multiple-photon-added coherent states (MPACSs), thermal states (MPATSs) and displaced thermal states (MPADTSs). Their analytical tomograms are actually the finite-summation representations related to single-variable Hermite polynomials. Besides, the numerical results indicate that the larger photon-addition number can lead to the multi-peak tomographic distributions for these three states, and the measurable tomograms of MPACSs and MPADTSs exhibit π-periodic features but MPATSs can’t.
关键词： multiple-photon-added Gaussian states,quantum state,Hermite polynomials,optical tomogram
更新于2025-09-09 09:28:46