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在近场光学扫描显微镜及其它一些以扫描方式成像的系统中,由于图像是逐行扫描而成,因此扫描图像行与行之间存在较大的噪音.针对这种情况及相应的含噪近场光学图像模型,并结合对近场光学扫描图像及其行噪音特点的分析,提出了根据图像行间相关性寻找行噪音补偿因子.同时考虑图像背景波动性选择噪音补偿因子,以此进行行噪音的消除.在此基础上,利用小波变换进一步处理,消除随机起伏噪音.实验结果表明,本方法可以快速有效地去除扫描图像行噪音,且适用于各类扫描图像的处理. 相似文献
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结合小波变换与微分法改善近红外光谱分析精度 总被引:3,自引:2,他引:3
微分法可以有效消除光谱背景和基线漂移,同时会增加光谱噪音;小波变换具有很好的去噪功能,章将微分法和小波变换结合用于重整汽油辛烷值近红外光谱分析。考察了微分噪音对辛烷值分析精度的影响以及小波去噪对微分光谱的噪音扣除以及对辛烷值分析精度改善情况。结果表明,微分光谱可以扣除原始光谱的基线漂移,提高分析精度,同时增加光谱的噪音;噪音对分析精度影响很大。微分光谱经过小波去噪处理后信噪比增加,辛烷值分析精度得到改善。 相似文献
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根据光纤陀螺输出信号的特点和应用环境的要求,在Mallat小波变换的基础上,研究了一种多算法融合的实时滤波算法.该算法在光纤陀螺刚启动,数据量偏少时,通过IIR滤波器进行滤波|采样数据量足够多时,通过施加滑动数据窗来实现小波实时去噪,采用周期对称延拓的方法去除小波去噪的边界问题,可有效去除光纤陀螺输出信号中高频部分的噪音,提高滤波效果,抑制陀螺的随机漂移.通过实验验证了该方法对陀螺输出信号进行滤波的可行性和有效性. 相似文献
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基于复小波和局部梯度的靶标图像混合降噪 总被引:2,自引:2,他引:0
提出了一种有效去除光电成像测量系统中靶标图像噪音的混合降噪法.根据图像像素局部梯度模找出图像中受椒盐噪音污染的像素,使用中值滤波降噪.对去除椒盐噪音的图像,利用复对数Gabor小波提取各像素的相位信息和幅度信息,确定最小尺度滤波器对噪音幅度分布的估计值,从而自动地确定各个尺度上的噪音幅度分布的估计值和噪音萎缩阈值,达到有效降噪的目的.实验表明,该方法的降噪效果明显优于实symlet4小波、中值滤波和单一复对数Gabor小波降噪法. 相似文献
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Huimin Xie Zhanwei Liu Daining Fang Fulong Dai Haixia Shang 《Optics and Lasers in Engineering》2005,43(8):904-918
Some novel nano-Moiré methods have been developed at failure mechanics lab in the Tsinghua University, recently. This paper offers an introduction of these new methods, which can be realized under the atomic force microscope, scanning tunneling microscope, as well as the transmission electron microscope. These nano-Moiré methods are able to offer quantitative analysis to nano-deformation of object. The measurement principles and experimental techniques of these methods are described in detail. A new digital nano-Moiré technique is proposed. Some typical applications to these methods are discussed. The successful experimental results demonstrate the feasibility of these methods and also verify that the methods can offer a high sensitivity for displacement measurement with nano-meter spatial resolution. 相似文献
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A variety of methods for the investigation and 3D representation of the inner structure of materials has been developed. In this paper, techniques based on slice and view using scanning microscopy for imaging are presented and compared. Three different methods of serial sectioning combined with either scanning electron or scanning ion microscopy or atomic force microscopy (AFM) were placed under scrutiny: serial block-face scanning electron microscopy, which facilitates an ultramicrotome built into the chamber of a variable pressure scanning electron microscope; three-dimensional (3D) AFM, which combines an (cryo-) ultramicrotome with an atomic force microscope, and 3D FIB, which delivers results by slicing with a focused ion beam. These three methods complement one another in many respects, e.g., in the type of materials that can be investigated, the resolution that can be obtained and the information that can be extracted from 3D reconstructions. A detailed review is given about preparation, the slice and view process itself, and the limitations of the methods and possible artifacts. Applications for each technique are also provided. 相似文献
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In this paper, a theoretical model of the acquisition in intersatellite optical communications (IOC) is founded with the assumption that beacon pointing errors could be modeled as Gaussian random variables. An optimal scan method should be chosen according to the average acquisition time under a certain acquisition probability. With analysis of the most common scan methods during the establishment of IOC, the raster-spiral scanning can substitute the spiral scanning is found. The raster scanning and raster-spiral scanning are simulated using Monte Carlo method and the result shows the first one is optimal for acquisition in IOC. 相似文献
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1 Introduction Forveryhighdatarates,intersatelliteopticalcommunications (IOC)holdapotentialperformanceedgeovermicrowave (RF )communicationsintermsofhigherdatarates,smallerantennasandlow probabilityofjammingandintercept[1] .WiththewidedevelopmentofIOCtechnol… 相似文献
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Extended branched networks of single-nanoparticle chains have recently been self-assembled from colloidal suspensions. In particular, gold nanoparticle linear chains and complex chain networks have revealed unique signatures of plasmon modes in their extinction spectra. In this Letter, we investigate theoretically their near-field optical properties and show that a real space mapping of these modes can be achieved with a photon scanning tunneling microscope setup. A distinct subwavelength patterning of the optical near-field gives rise to well-resolved photon scanning tunneling microscope images that can be used to identify the network segments able to efficiently carry optical energy. 相似文献
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A.V. Crewe 《Surface science》1975,48(1):152-160
The high brightness and small physical dimensions of a field emission source make it extremely attractive as the source of electrons in scanning electron microscopes. Using this kind of source considerable improvements have been made in this type of instrument so that at the present time the surfaces of solid objects can be viewed at a resolution of 30 Å and thin specimens can be viewed with a resolution of 2.5 Å. The particular nature of the scanning electron microscope allows some unique forms of contrast to be obtained so that the micrographs which can be taken with these microscopes are different in content and quality than those taken on conventional microscopes. As one example, we have been able to study the motion of single heavy atoms on thin carbon films. The resolution is, of course, not as high as that which can be obtained with a field ion microscope but the kind of specimen which can be viewed is different so that the two instruments are complementary in nature. 相似文献
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If a laser beam illuminates a continual deformation object surface, it will lead to a temporal speckle pattern on the observation plane. Recording this time-dependent speckle pattern the deformation of the surface of an object can be obtained. Two methods, scanning phase method (SPM) and time sequence phase method (TSPM), have been introduced for measuring the displacement caused by the deformation in temporal speckle pattern interferometry (TSPI). Their principle is that by capturing a series of speckle interference patterns related to the object deformations, the fluctuations in the intensity of the interference patterns can be obtained. Through scanning these fluctuations and estimating both the average intensity and modulation of the temporal speckle interference patterns, the phase maps for whole-field displacements are calculated. In this way one is capable of quantitatively measuring continual displacements simply using a conventional electronic speckle pattern interferometry (ESPI) system without phase shifting or a carrier. The elaboration on the new methods is given in this paper and experiments are performed to demonstrate their performance with a conventional ESPI system. 相似文献
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共焦激光扫描荧光显微镜的扫描系统研究 总被引:1,自引:0,他引:1
本文简述共焦激光扫描灾光显微镜的基本原理,提出扫描系统的方案确定和优化设计的方法,使用该方法何使扫描渐晕减少为原来的1%。同时还给了扫描控制系统运行和控制法以及是均匀图的补偿方法。 相似文献
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本文讨论了计算全息激光扫描器的基本原理,详细推导出平移型二维等间距线阵扫描器的位相函数表达式和平移型二维抛物线扫描器的位相函数表达式。本文还详细介绍了上述二种扫描器的制作方法,并给出实验结果。对于等间距线阵扫描器,作者提出了一种简单易行的制作方法。 相似文献