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1.
针对雾气环境下实际图像亮度/对比度不佳的情况,提出了整体灰度拉伸和局部对比度增强算法,改善了图像的亮度和对比度。采用基于暗原色先验的图像去雾算法来去除视频监控中常常遇到的雾霾影响。为了消除块效应,将图像分成最小的块,即对每个像素提取暗原色,并采用邻近相似性原则修正暗原色,MATLAB仿真表明,改进后的算法可以很好地去除图像中的雾气。最后,完成了基于达芬奇DM6467的图像增强算法软件开发,实现了4路视频的输出、切换和图像增强。增强后的图像,其SSIM指标可提高50%以上,该系统可以有效地去除雾气对图像的影响,满足图像去雾增强的需要。  相似文献   

2.
娄越  相里斌  刘波 《光子学报》2007,36(9):1759-1763
在分析海天背景下目标红外图像特征的基础上,提出了一种基于背景粗糙度估计的红外目标自适应检测算法.该算法利用LOG算子进行目标基本轮廓检测,将目标的中心点作为区域生长的种子点,通过背景粗糙度估计自适应确定LOG算子参量,完成目标图像分割.与传统检测方法比较,采用该处理方法进行小目标检测及识别过程的预处理,可以有效地减少运算量,提高检测速度,抑制对不必要的种子点进行区域生长,提高了目标的检测概率.  相似文献   

3.
基于DSP阵列的海面目标红外图像实时仿真系统研究   总被引:1,自引:0,他引:1  
从海面目标红外辐射特性研究的具体需求出发,给出了一种用于生成海面目标红外图像的仿真算法,在此算法基础上提出了一种基于DSP阵列的海面目标红外图像实时仿真系统,并对其系统构成、DSP阵列硬件实现、仿真算法并行处理等内容进行了具体描述。仿真实验结果表明该系统能满足海面目标红外图像实时仿真的基本要求,在同等仿真精度下其仿真实时性远高于其他通用计算平台。  相似文献   

4.
基于多尺度分析的激光光条中心点坐标提取方法   总被引:1,自引:0,他引:1  
在线结构光测量系统中,激光光条图像中心准确提取是影响整个测量系统精度的关键因素之一。针对高反光等复杂环境下光学测量中激光光条图像中心提取问题,提出了一种基于多尺度分析的激光光条图像中心高精度定位方法。该方法利用骨骼化图像处理方法确定激光光条图像中心的初值,根据每一个光条中心初值处的光条宽度确定该位置处对应的高斯核均方差σ的初值。对图像进行多尺度卷积,确定最优的σ值,并求得光条亚像素级中心点,最后完成光条链接。结果表明该算法抗噪声能力强,可实现光条宽度变化较大的激光光条图像中心的高精度提取。  相似文献   

5.
剪切光束成像技术是一种非传统散斑成像技术,能透过扰动介质对远距离目标进行高分辨率成像.本文提出了一种基于全相位谱分析的图像重构算法,利用全相位谱分析对回波信号数据进行预处理,可有效抑制频谱泄露,校正散斑频谱,消除多种因素引起的频率漂移误差,得到准确的散斑强度和相位差,提高实际成像环境的系统成像能力.仿真结果表明:该图像重构算法有效抑制了频率漂移对成像质量的影响,当信号存在频率误差时,其成像效果大大优于基于传统傅里叶变换谱分析的重构算法.  相似文献   

6.
张华  王金兰 《应用声学》2017,25(4):36-36
在物联网环境下进行信息监控系统设计,实现对网络信息的监控和自适应采集,保障网络安全。针对采用传统的神经网络控制方法进行信息监控的数据挖掘准确性不好的问题,提出一种基于物联网和自组织映射SOM算法的信息监控系统设计方法,首先进行信息监控系统的总体设计和功能模块化分析,然后设计改进的SOM算法,应用在信息监控的数据挖掘和分类识别中,在程序加载模块中进行算法加载,最后在物联网环境下构建嵌入式Linux内核进行信息监控系统的软件设计和开发。系统仿真实验结果表明,采用该信息监控系统进行大型物联网的数据信息监控,对数据的准确挖掘和识别性能较好。  相似文献   

7.
段建民  田奇 《应用声学》2015,23(7):2255-2258
针对自动光学检测(AOI)平台运行过程中的定位精度控制问题,提出了一种基于速度和加速度前馈控制与PID反馈控制的复合控制算法,该算法对输入量进行跟踪补偿控制以消除系统稳态误差,用于提高AOI平台定位精度。基于开放式的数控系统设计方法设计了AOI平台。在Matlab/Simulink环境下,构建了基于该复合控制算法的定位精度控制仿真模型,仿真结果验证了复合控制算法的有效性。将该复合控制算法作为ACR9000控制器的控制算法,并基于ACR9000控制器进行AOI平台实验研究。应用该AOI平台进行了印刷电路板(PCB)检测实验,实验结果表明文中复合控制算法能够提高AOI平台定位精度,AOI平台的定位精度满足印刷电路板检测要求,可以将该AOI平台用于印刷电路板检测。  相似文献   

8.
提出了一种基于迭代振幅-相位恢复算法和非线性双随机相位编码的图像加密方法。该方法利用两个公开密钥和一幅"假图像"在非线性双随机相位加密系统中生成密文,接着利用迭代非线性双随机相位编码生成两个私有密钥。待加密图像和密文作为迭代加密方法中的两个限定值。解密过程则可以在经典的基于4f系统的线性的光学双随机相位编码系统中完成。该加密方法具有迭代收敛速度快、安全性高的优点。迭代该图像加密方法能够抵御最近提出的基于改进的振幅-相位恢复算法的攻击。理论分析和仿真实验都证明了此方法的有效性和可靠性。  相似文献   

9.
针对主动磁悬浮轴承系统具有强非线性、强耦合、模型不确定等特点,提出了一种变论域自适应模糊PID算法。该方法通过选择合适的伸缩因子,避免了传统模糊PID控制中出现规则爆炸的问题。同时针对传统伸缩因子的函数结构和参数难以确定的特点,设计了基于模糊规则的论域伸缩因子。在SIMULINK环境中对主动磁悬浮轴承系统进行仿真,仿真结果表明,变论域模糊PID算法控制的主动磁悬浮系统具有更好的动静态性能,对外界干扰具有更强的鲁棒性。  相似文献   

10.
非结构化环境下机器人视觉导航的路径识别方法   总被引:2,自引:0,他引:2  
提出了一种基于模糊粗糙集的非结构化路径识别与机器人引导方法。通过自适应面阵列电荷耦合传感器的图像清晰度控制方法,获取了最佳信息量图像。构建了模糊粗糙集的非结构化路径识别模型,借助粗糙集理论预定义图像目标、背景和不确定区域,融合相对模糊连接度竞争机制对不确定区域的像素进行了模糊重分类,精确描绘了机器人的导航路径。该模型可实现未知非结构化路径区域的自动识别,亦可引入灰度先验特征识别指定路径区域。结果表明,该方法对提高机器人在非结构化环境中的自主探索能力具有实际意义。  相似文献   

11.
Calculated vibrational frequencies are reported for the PMo12O40 3– ion according to a 53-atomic tetrahedral model (Td). The results are compared with calculated frequencies for fragments of this structure, viz. PO4 (Td), Mo3O13 (C3v), Mo3O7 (C3v, Mo2O11 (Cs) and Mo2O10 (Cs).

A complete vibrational analysis of the PMo12O40 3– ion has been performed. The adopted model of Td symmetry is an idealization of x-ray structure data. 1 The normal modes of vibration according to this model are distributed as:  相似文献   

12.
Small molecule sorption and desorption in and out of Iota‐Carrageenan was studied by using steady‐state fluorescence (SSF) technique. Pyranine dissolved in water used as fluorescence probe. Fluorescence emission intensity, I p from pyranine was monitored for studying sorption and desorption processes at various temperatures. The Fickian model was applied to produce sorption, Ds, early desorption, Ded, and desorption, Dd, coefficients. Corresponding activation energies were obtained and found to be 20.5 kJ mol?1, 7.0 kJ mol?1 and 34.9 kJ mol?1, respectively. The observed Ded value is an order of magnitude smaller than the Ds and Dd coefficients. On the other hand, sorption processes were shown to be twice as fast as desorption processes.  相似文献   

13.
DSC and complex impedance studies of the protonic conductor (NH4)4H2(SeO4)3, which undergoes a superionic phase transition of first order at Ts = 378 K show that the activation energy of ionic conductivity d(lg σ)/dt and the ordering enthalpy ΔCp of the crystal are proportional: d(lg σ)/dT = XΔCp/RTs + const, as found for MAg4I5 crystals undergoing a second-order superionic phase transition. Thus the short-range order environment of the species involved in fast-ion transport plays the main role in the superionic phase transition. This is also supported by the value of the entropy change at Ts, ΔS = 43 J/mole·K. A new metastable phase was found to be induced on heating the (NH4)4H2(SeO4)3 crystal above Ts.  相似文献   

14.
Microcosmic investigations of weak red-emitting materials are crucial for their further development and application. In this work, we have focused on the band structures and electronic properties of Pr mono- and (Zn, Pr) co-doped CaTiO3 using density functional theory. Zn substitution for Ca or Ti tends to form clusters energetically with Pr substituting for Ca in CaTiO3. In Pr mono-doped CaTiO3, the O2p→Ti3d transition in CaTiO3 host corresponds to the centered 330 nm excitation spectra. The gap states above the valence band of ∼1.30 eV and ∼2.06 eV are hybridized by Pr4f, O2p and Ti3d orbitals. They are mainly due to Pr4f orbitals in CaTiO3:Pr. The former gap level is related to red emission at 614 nm due to 1D23H4 transition of Pr3+ activator. The latter is related to the excitation spectra centered at 380 nm due to the low-lying Pr-to-mental intervalence charge transfer transitions (Pr3+-O2−-Ti4+?Pr4+-O2−-Ti3+). The band structures of (Zn, Pr) co-doped CaTiO3 keep the similar gap levels to those in Pr mono-doped CaTiO3. The incorporation of Zn brings out the two stronger localized gap states, which are hybridized by Pr4f, O2p and Ti3d orbitals, in comparison with those in Pr mono-doped CaTiO3. Therefore, when Zn impurities are added into Pr doped CaTiO3, the present calculations visualize the two enhanced levels and the distorted structures around Pr.  相似文献   

15.
C42+的几何构型和Jahn Teller效应   总被引:1,自引:0,他引:1       下载免费PDF全文
汪蓉  朱正和  杨传路 《物理学报》2001,50(9):1675-1680
用从头计算法QCISD/6-311G得到了C42+分子的10种不同的几何构型,其中包括Cs,C∞v,C2v,D2h,D∞h,D4h,D2d,C3v等不同的构型.计算表明C42+的Td构型不能稳定存在,详细讨论了Td 关键词: 几何构型 42+')" href="#">C42+ Jahn Teller效应  相似文献   

16.
Zn0.95−xCo0.05CuxO (ZCCO, where x = 0, 0.005, 0.01 and 0.015) thin films were deposited on Si (1 0 0) substrates by pulsed laser deposition technique. Crystal structures, surface morphologies, chemical compositions, bonding states and chemical valences of the corresponding elements for ZCCO films were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and X-ray photoelectron spectroscopy (XPS). XRD and FESEM results indicate that crystallite sizes of the highly (0 0 2)-oriented ZCCO films slightly decrease with increasing Cu content. When the Cu content increases from 0 to 0.015, Zn 2p3/2, Co 2p, Cu 2p3/2 and O 1s peaks of the ZCCO film shift towards higher or lower binding energy regions, and the reasons for these chemical shifts are investigated by fitting the corresponding XPS narrow-scan spectra. Both in-plane and out-of-plane magnetization-magnetic field hysteresis loops of the ZCCO films reveal that all the films have room temperature ferromagnetisms (RTFMs). The conceivable origin of the RTFM is ascribed to the combined effects of the local structural disorder resulted from (Co2+, Cu2+, Cu1+)-cations which substitute Zn2+ ions in the ZnO matrices, ferromagnetic coupling between coupled dopant atoms caused by Co2+ (3d74s0) and Cu2+ (3d94s0) spin states, and exchange interactions between the unpaired electron spins originating from lattice defects induced by Cu doping in the Zn0.95Co0.05O matrices.  相似文献   

17.
The electrical transport coefficients of anti-ferromagnetic CaMnO3 have been investigated by density functional theory calculation within generalized gradient approximation. The calculated transport coefficients exhibit the anisotropic nature, in agreement with its electronic states. The transport property results reveal the stronger carrier transport along the O1–Mn–O1 plane within the O–Mn–O octahedron, indicating that the Mnd and O1p orbitals are mainly responsible for electrical transport. The maximum power factor values as a function of relaxation time reach 8.4×1023 Wm−1 K−2 s−1, 7.9×1023Wm−1 K−2 s−1 and 4.9×1023 Wm−1 K−2 s−1 within c, a and b direction, respectively. The dimensionless figure of merit ZTxx, ZTyy as well as ZTzz is estimated with 1.28, 0.8 and 1.37 at 1000 K, respectively.  相似文献   

18.
An optical study of a Y0.99Pr0.01PO4 single crystal is presented. Measurements of optical absorption, excitation, and emission by selective excitation into 1D2, 3P0 and 3P1, at different temperatures between 20 and 295 K, are described. A detailed account of the line assignments is given for absorption in the 4300-23 000 cm−1 spectral range, and for emission in the 6400-23 000 cm−1 range. The lifetimes of the emitting levels are determined. Vibronic sidebands accompanying absorption, emission and excitation spectra are reported. The decay processes of the 3P1, 3P0 and 1D2 levels are discussed. The aim of this study is a test of the configuration-interaction-assisted crystal field analysis as well as the accurate experimental determination of the energy level scheme. It was reported previously that the introduction of configuration interaction between the ground 4f2 configuration with the excited 4f6p configuration always resulted in a decrease (≈50-60%) in the standard deviations between the observed and calculated energy levels. In the present work the 4f5d configuration is included as well. The crystal field is analysed in the theoretical D2d site symmetry with and without configuration interaction. The results with 4f2, 4f2+4f5d, 4f2+4f6p and 4f2+4f5d+4f6p are given. The calculation on the basis of the 315 (4f2+4f5d+4f6p) levels gives the best overall standard deviation lowering it by 75% with regard to the calculation on the 91 4f2 levels only.  相似文献   

19.
Theoretical calculations on the fine, hyperfine and Zeeman (g-factor) parameters are reported for the X2Π and A2Σ+ states of FH+, ClH+ and BrH+. The fine-structure constants [spin–orbit (A), Λ-doubling (p, q) and spin–rotation constants (γ Π, γ Σ)] are evaluated up to second order (via SO/L couplings with several excited states) using a multireference configuration interaction (MRCI) method, a Breit–Pauli Hamiltonian and 6-311++(2d,2pd) basis sets. Hyperfine constants of magnetic and electric type [Frosch–Foley (a, b, c, d) and nuclear quadrupole (eQq 0, eQq 2)] are studied with density functional methods and various basis sets. Magnetic dipole moments (parameterized via g-factors) are calculated in second order like the fine structure constants. The situation is somewhat complex for X2Π since no less than five different gs have to be evaluated in second order. In general, our results are in good agreement with those reported in the literature, mostly limited to the ground state. Our calculations confirm that, at equilibrium, all second-order properties are dominated by the couplings between the electronic states X and A.  相似文献   

20.
In order to elucidate the anisotropic pressure effect on superconductivity in an iron-based superconductor, magnetization measurements have been performed in Ba(Fe0.92Co0.08)2As2 single crystals under uniaxial pressures applied along the c-axis. Gigantic Tc suppression, dTc/dP//c = −15 K/GPa, was observed when the anisotropic deformation with the a-expansion and c-compression was induced by the c-pressure, which should be compared with dTc/dP < +1 K/GPa in the isotropic pressure case. This suggests that the a-axis (c-axis) compression has a positive (negative) contribution to Tc.  相似文献   

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