共查询到20条相似文献,搜索用时 62 毫秒
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本文, 基于经典统计光学, 建立符合热光特性的统计模型, 通过数值模拟证明了吴令安和Meyers提出的图像重构算法, 并进行了定性的理论分析. 在关联成像获得的数据样本中, 根据桶探测器的光强涨落进行分组, 分别以某个阈值作为下限和上限, 再将分组后的独立样本和相应的面探测器信号进行强度关联, 则可以得到物体的正像或负像. 然而, 不经过关联运算, 直接对分组后的面探测器信号进行算数平均也可以得到物体的正像或负像, 同时成像的对比度得到较大提高. 这种分组对应的非定域成像进一步说明强度涨落在热光成像中的重要性. 最后以字符掩膜版作为成像物体, 分别运用关联成像和分组对应正负成像算法重构物体的图像, 实验结果证明这种新的正负算法可以提高非定域成像的对比度.
关键词:
统计光学
热光
关联成像
正负非定域成像 相似文献
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On the basis of a state-of-the-art aberration-corrected transmission electron microscope, the spherical aberration coefficient CSof the objective lens can be tuned to either a positive or a negative value. The use of a negative value of CS combined with an overfocus setting of the objective lens leads to the development of the negative CSimaging(NCSI) technique. Images obtained using the NCSI technique show superior contrast and signal intensity at atomic column positions than the corresponding positive CSimages, especially for weakly scattering oxygen columns that are in close proximity to strongly scattering cation columns in oxides. Based on the images obtained under the NCSI condition, quantification of the image contrast allows measurements of the atom positions with a precision of a few picometers and the local chemistry on atomic scale. In the present review, we discuss firstly the benefits of the NCSI technique in studies of oxide materials,and then show a procedure for quantitative analysis of the image based on the absolute value of contrast. In the last part,examples are given for the application of the quantitative high-resolution transmission electron microscopy(HRTEM) to the study of electric dipoles of oxide ferroelectrics and atomic-scale chemistry of interfaces. 相似文献
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We demonstrate a new implementation of complex spectral optical coherence tomography (OCT) in biomedical imaging. By reconstruction of both amplitude and phase we are able to use the negative and positive optical path differences to get images of objects of considerable thickness. An accompanying reduction of coherent noise improves the quality of the images. The property of the complex spectral OCT that permits the measurement range to be increased and permits the simultaneous use of phase and amplitude in spectral systems was not described previously. To show the potential of this technique we measured an anterior chamber of a porcine eye in vitro. 相似文献
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Abdullah Bal 《Optik》2006,117(1):1-8
Subband multiresolution technique presents decomposition and reconstruction properties for 2D images using multichannel spatial filtering. Each subband image represents multiresolution of the input image. In this paper, optic subband multiresolution architecture is proposed based on multi-object phase-only joint transform correlator (JTC). Multichannel filtering is realized using multi-object input joint image that includes bipolar data. The bipolar data (containing positive, zero and negative values) is encoded by phase in the input and Fourier planes of the phase-only JTC. For image decomposition and reconstruction, two optoelectronic subband multiresolution architectures have been developed. Each architecture has been tested using a simulation program. 相似文献
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The images to be compared are reproduced in the form of dot images by the usual printers techniques. We use a positive dot image of the first one, and a negative of the second one. The difference can be obtained either by multiplying the two intensities or by adding them. 相似文献
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A method of reconstructing positive and negative images from Fourier holograms recorded without the dc components is demonstrated by use of a coaxial holographic storage system. Reconstructed images are obtained by adding a phase-modulated dc component of the signal beam on reading. Contrast reversal of the reconstructed images can be achieved by reversing the readout reference pattern. This method can realize not only optical noise reduction but also less consumption of the dynamic range of the recording medium, potentially contributing to increasing the number of multiplexed holograms. 相似文献
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研究了一种处理大运动模糊图象的非相干光方法:利用光密度严格“互补”的正、负片,直接对图象微分,以获取处理象。既可处理平动模糊图象,又可处理用目前相干光方法难以处理的转动模糊图象。 相似文献
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The basic TDLMS (Two-Dimensional Least Mean Square) filter fails to detect infrared small targets consistently, especially under conditions of heavy noise and distinct cloud edges. This paper proposes a robust and efficient small-target detection method based on the basic TDLMS filter. The method first smooths the input image with a Gaussian filter of adaptive variance, and then employs TDLMS with a selected step size to filter the image with rightward and leftward iterations. Two prediction error images are obtained by subtracting the prediction images of the bilateral filtering from the original input image. Each prediction error image is separated into positive and negative prediction error images. That is, four images are generated in the bilateral filtering. The final image is obtained by fusing these four images. Experimental results show that the proposed method achieves significant improvement in background suppression and detection performance over the basic TDLMS filter and other improved TDLMS filters. 相似文献
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《中国物理 B》2018,(12)
We present the joint probability density function(PDF) between the bucket signals and reference signals in thermal light ghost imaging, by regarding these signals as stochastic variables. The joint PDF allows us to examine the fractional-order moments of the bucket and the reference signals, in which the correlation orders are fractional numbers,other than positive integers in previous studies. The experimental results show that various images can be reconstructed from fractional-order moments. Negative(positive) ghost images are obtained with negative(positive) orders of the bucket signals. The visibility and peak signal-to-noise ratios of the diverse ghost images depend greatly on the fractional orders. 相似文献
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四通道自成像计算全息 总被引:1,自引:0,他引:1
描述了一种新型的计算全息,它在双通道计算全息基础上通过对物谱加正的或负的二次位相因子,能一次对四个不同的物进行编码,现现时在四个不同的方向上分别产生它的像,并具有自成像的特性。文中给出了实验结果。 相似文献
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Fischer R Hanson KM Dose V von Der Linden W 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》2000,61(2):1152-1160
A general probabilistic technique for estimating background contributions to measured spectra is presented. A Bayesian model is used to capture the defining characteristics of the problem, namely, that the background is smoother than the signal. The signal is allowed to have positive and/or negative components. The background is represented in terms of a cubic spline basis. A variable degree of smoothness of the background is attained by allowing the number of knots and the knot positions to be adaptively chosen on the basis of the data. The fully Bayesian approach taken provides a natural way to handle knot adaptivity and allows uncertainties in the background to be estimated. Our technique is demonstrated on a particle induced x-ray emission spectrum from a geological sample and an Auger spectrum from iron, which contains signals with both positive and negative components. 相似文献
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We demonstrate the polarization of resistive switching for a Cu/VOx/Cu memory cell.The switching behaviors of Cu/VOx/Cu cell are tested by using a semiconductor device analyzer(Agilent B1500A),and the relative micro-analysis of I-V characteristics of VOx/Cu is characterized by using a conductive atomic force microscope(CAFM).The I-V test results indicate that both the forming and the reversible resistive switching between low resistance state(LRS) and high resistance state(HRS) can be observed under either positive or negative sweep.The CAFM images for LRS and HRS directly exhibit evidence for the formation and rupture of filaments based on positive or negative voltage.The Cu/VOx/Cu sandwiched structure exhibits reversible resistive switching behavior and shows potential applications in the next generation of nonvolatile memory. 相似文献
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Arturo Carnicer Santiago Vallmitjana JosRamn de F. Moneo Ignacio Juvells 《Optics Communications》1996,130(4-6):327-336
An original method to detect images in defocused scenes by means of a binary joint transform correlation is presented. Defocused images are described in frequency domain as the product between the Fourier transform of the in-focus scene by the optical transfer function of the imaging lens. This function, which presents positive and negative values, introduces sign errors in the joint power spectrum. The goal of this study is to detect the sign of the optical transfer function starting from the defocused image by means of a digital algorithm. Information provided by the algorithm allows to compensate the sign errors in the binary joint power spectrum and to obtain invariant correlations with respect to defocusing. Theoretical analysis and digital experiments to test the procedure are provided. 相似文献
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In this work, we present a rather simple method to study the Casimir effect on a spherical shell for a massless scalar field with Dirichlet boundary condition by applying the indefinite metric field (Krein) quantization technique. In this technique, the field operators are constructed from both negative and positive norm states. Having understood that negative norm states are un-physical, they are only used as a mathematical tool for renormalizing the theory and then one can get rid of them by imposing some proper physical conditions. 相似文献
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Kokhanchik LS 《Micron (Oxford, England : 1993)》2009,40(1):41-45
The different lithium niobate crystals with opposite domain structure (ODLN) were studied in the SEM using e-beam negative surface charging. In the ODLN the polarization vector Ps alternates periodically "tail-to-tail" and "head-to-head" and arranges perpendicular to the domain boundaries. In the investigation we have used congruent LiNbO(3) crystals (CLN) and Cr(2)O(3)- and In(2)O(3)-doped LN with the ODLN structure. Initial surface potential images in secondary electron (SE) mode and charge accumulation on the Y-cut surfaces of different LiNbO(3) crystals were compared. The initial surface potential relief in ODLN was found to depend on the position of "tail-to-tail" and "head-to-head" domain walls in the structure. In the doped LN with the periodical domain structure formed during the growth process, the surface potential changes near the domain walls are much weaker than in the structures of CLN obtained by the aftergrowth thermoelectrical treatment technique. A well-defined SE image of "tail-to-tail" domain walls was observed upon special surface negative charging in all types of investigated LN crystals. The negative surface charging in the "tail-to-tail" domain wall areas proceeded slower and the SE exit from these areas decreased as compared to other crystal areas. The charging conditions for the domain wall observation in all samples were comparatively analyzed. The width and uniformity along the boundary images were different and correlated with doping in the crystals. The formation of different charge images could be explained by a variety of positive point defect distributions near the "tail-to-tail" domain walls in different LN crystals. The defects and doping ions screen polarization charges in the "tail-to-tail" wall area and can influence recombination rates of charges induced by an electron beam. Therefore, these domain wall areas are charged much weaker at negative surface charging than other domain areas. This SEM approach could afford a possibility to compare the distribution of the defects that screen the polarization charges and accumulate near the ferroelectric domain wall areas in LN crystals. 相似文献
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Approach to Generate Radiometric Images 总被引:5,自引:0,他引:5
QuanLiang Huang ZuYin Zhang Wei Guo 《International Journal of Infrared and Millimeter Waves》2001,22(12):1805-1811
A new technique to generate radiometric images from the optical images is introduced in this paper. This technique can be applied in generating the source images for purpose of image-matching navigation. For comparison, two radiometric images are presents, one is imaged by a 8mm ground-based radiometer and the other is generated by this technique. 相似文献
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Two characteristic types of spots which are frequently found in electron mirror microscope images are interpreted as caustic cross sections caused by local surface charges. Negative charges produce dark circular spots with a bright edge while the caustic cross sections produced by positive charges are of the type well known from the caustic surfaces of electron lenses suffering from spherical aberration and astigmatism. The bright edge in the negative caustic is accompanied by a second edge which in all practical cases is much less intense and consequently invisible. 相似文献