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1.
斜光束对校正滤色器校正精度的影响 总被引:2,自引:0,他引:2
当用测色仪器按照国际照明委员会规定的条件测量物体颜色时 ,若样品与探测器之间的距离不够大 ,则斜光束会透过校正滤色器而被探测器接收 ,这时对应探测器某点校正滤色器的当量透射比可以用修正计算式求得。以“Y”校正滤色器为例 ,从计算结果和实验说明了斜光束对校正滤色器透射比的影响。 相似文献
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彩色条纹滤色器在单管彩色电视摄像系统中起着分色作用。它的光谱透过率曲线被称为分色曲线,是根据色度学原理设计计算的。分色曲线对整机彩色复现性能有重要的影响。但是在制造过程中分色曲线是达不到设计计算的曲线的。有误差存在。但究竟误差范围是多大才是允许的范围,我们根据色度学原理进行了计算和分析,得出了初步的结论,以提供整机彩色性能分析和制作彩色膜的参考。 相似文献
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光学模拟测色仪采用校正滤色器使仪器满足卢瑟条件 ,校正滤色器的精度受多种因素的影响。详细地分析了影响校正滤色器精度的因素 ,并阐明了提高校正滤色器精度的方法及原理。 相似文献
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《光学学报》2020,(4)
基于多目标优化方法,针对几个常用于评价多光谱相机性能的参数峰值信噪比(PNSR)、拟合优度系数(GFC)、CIE色差评价系数(CIEDE2000)和均方误差(MSE),及其对应的最大值或最小值,按照最优排序集分的方法,得到了各评价参数均可以得到较好取值的最优滤色器。和前期研究相比,待选滤色片数量由45增加为1035,同时成像场景的反射率样本数量由24增加为1269。结果表明,待选滤色片数量和反射率向量空间增加后,最优滤色器的性能更好;同时描述最优滤色器的光谱透过率向量矩阵自身的三个参数即滤色器向量矩阵的条件数(Cond)、峰值均匀度指数(UF)和相邻滤色片交叠度指数(OLP)的数值也更加稳定。实验结果可为通过滤色器向量矩阵定量选取宽带多光谱滤色片提供参考。 相似文献
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猫眼逆向器作为谐振腔镜与一个凹面镜构成猫眼激光谐振腔.精确计算了三种猫眼逆向器(即理想猫眼逆向器和两种存在误差的猫眼逆向器)的逆向平行反射性,并对应用这三种猫眼逆向器的谐振腔中高斯光束的各项参数进行了深入分析,得出结论:对于高斯光束,凸透镜的焦距、凹面镜曲率半径、凸透镜与凹面镜间距三者相等的猫眼逆向器为理想逆向器,其逆向平行反射性最好,此时猫眼谐振腔处于理想状态,基模模体积最大,远场发散角最小,稳定性最好;在猫眼谐振腔的设计中,要尽量减小猫眼逆向器中凸透镜的焦距,增大凹面输出镜的曲率半径;猫眼逆向器存在误差时谐振腔的各项性能将受到影响.为猫眼谐振腔激光器的设计提供了理论依据. 相似文献
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彩色条纹滤色器是一种新型的光学元件。它己被成功地应用於彩色信息变换和处理方面。而它最有应用价值的地方还是在各种摄像器件当中。它可以制作多种彩色条纹摄像管,进而制作各种小型的单管彩色摄像机和超小型的彩色固体摄像机,在工业彩色电视和广播彩色电视技术中发挥较大的经济效益。在变像管彩色化的研究方面也有应用价值。本文着重讨论了彩色条纹滤色器的设计、性能、及其在摄像管和变像管彩色化方面的应用。 相似文献
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由于传声器阵列通常对阵元失配误差较为敏感,因此稳健波束形成器的设计已成为传声器阵列处理领域的研究热点之一。概率密度法是目前传声器阵列稳健波束形成器设计中的一类重要方法,但该方法所需的阵元失配误差的概率密度信息在实际中较难获取。针对这一问题,本文研究了基于阵元失配误差低阶统计量的稳健波束形成器设计方法,该方法仅利用在实际中较易获取的阵元失配误差的一阶和二阶统计量信息。本文分别研究了基于阵元失配误差低阶统计量的固定权和变加权最小二乘波束形成器设计,给出了两种波束形成器的相关设计理论。理论和仿真分析表明,在小误差条件下,低阶统计量法所设计的波束形成器仍保持与概率密度法相当的性能。 相似文献
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基于一阶仄勒展开式的迭代最小二乘相移新算法 总被引:3,自引:3,他引:0
提出了一种新的最小二乘迭代算法,能有效消除因相移器存在导向误差面相移平面倾斜从而导致的相移误差。当相移器存在的相移误差包括位移误差与倾斜误差时,同一幅干涉图诸像素点的相移并不同步,但其相移量在同一平面上。求解此平面,即可消除相移误差。通过求新由一阶泰勒展开式得到的线性方程组,避免了为求解此平面而求解非线性议程组最小二乘解的过程,使算法简化,利用迭代法,保证求解的精度。并通过数值模拟,验证了这种算法在消除较大的相移器倾斜及位移误差影响上具有良好的效果。 相似文献
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本文通过滤色条与激光防护眼镜透射光谱平直化工作,探讨了对称周期高反射膜系主反射带两侧反射次峰的压缩问题。其基本思想是根据薄膜负滤光器设计原理,从等效概念出发,计算出由硫化锌、氟化镁和氧化锆、二氧化硅组成的两种高反射膜系基本周期的等效折射率,然后以变折射率法和变厚度法,分别计算出正配于玻璃与主膜系和主膜系与空间系之间的薄膜组合,并简述了取得的实验结果。 相似文献
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一种级联马赫-曾德尔滤波器设计的新方法 总被引:8,自引:2,他引:6
级联马赫—曾德尔干涉仪滤波器可实现平顶化的滤波器频谱响应,但是利用传统的传输矩阵法。并不能方便地得到级联马赫—曾德尔干涉仪滤波器中各耦合器的耦合系数。将级联马赫—曾德尔干涉仪滤波器与数字信号处理中的有限脉冲响应滤波器进行了类比,并将数字滤波器的设计方法引入到级联马赫—曾德尔干涉仪滤波器的设计中,将滤波器的传输函数表示成为各耦合器耦合系数的显式函数,同时利用遗传算法,计算了对于给定的滤波器频谱响应,级联马赫—曾德尔干涉仪光滤波器中各耦合器的耦合系数。通过实例证明了利用数字滤波器的设计方法及遗传算法设计级联马赫—曾德尔干涉仪光滤波器,不仅可以得到理想的结果,而且可以提高光滤波器的设计效率。 相似文献
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Nonlinear adaptive filters for high-speed LED based underwater visible light communication [Invited]
《中国光学快报(英文版)》2019,(10)
Underwater visible light communication(UVLC) is expected to act as an alternative candidate in nextgeneration underwater 5 G wireless optical communications. To realize high-speed UVLC, the challenge is the absorption, scattering, and turbulence of a water medium and the nonlinear response from imperfect optoelectronic devices that can bring large attenuations and a nonlinearity penalty. Nonlinear adaptive filters are commonly used in optical communication to compensate for nonlinearity. In this paper, we compare a recursive least square(RLS)-based Volterra filter, a least mean square(LMS)-based digital polynomial filter,and an LMS-based Volterra filter in terms of performance and computational complexity in underwater visible light communication. We experimentally demonstrate 2.325 Gb/s transmission through 1.2 m of water with a commercial blue light-emitting diode. Our goal is to assist the readers in refining the motivation, structure,performance, and cost of powerful nonlinear adaptive filters in the context of future underwater visible light communication in order to tap into hitherto unexplored applications and services. 相似文献
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High bit rates optical communication systems pose the challenge of their tolerance to linear and non-linear fiber impairments. Coherent optical receivers using digital signal processing techniques can mitigate the fiber impairments in the optical transmission system, including the chromatic dispersion equalization with digital filters. In this paper, an adaptive finite impulse response filter employing normalized least mean square algorithm is developed for compensating the chromatic dispersion in a 112-Gbit/s polarization division multiplexed quadrature phase shift keying coherent communication system, which is established in the VPI simulation platform. The principle of the adaptive normalized least mean square algorithm for signal equalization is analyzed theoretically, and at the meanwhile, the taps number and the tap weights in the adaptive finite impulse response filter for compensating a certain fiber chromatic dispersion are also investigated by numerical simulation. The chromatic dispersion compensation performance of the adaptive filter is analyzed by evaluating the behavior of the bit-error-rate versus the optical signal-to-noise ratio, and the compensation results are also compared with other present digital filters. 相似文献
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The resonance characteristics of a twisted-nematic liquid crystal Fabry-Pe′rot wavelength filter (TN-FP) is analysed and it
is shown that it obeys some simple laws hitherto unknown. A method to calculate the transmittance and eigenstate of polarizations
of the filter is first demonstrated. Next, approximate expressions of resonance wavelengths at some of the voltage regions
are derived and connection formulae for two series of modes are presented. Finally, a transition of the eigen polarization
in the FP etalon is investigated, and an interpretation of a paradoxical property concerning the longitudinal mode number
of the filter is given.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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A. A. Belyakov A. A. Mal'tsev S. Yu. Medvedev V. V. Cherepennikov 《Radiophysics and Quantum Electronics》1994,37(10):815-821
A modified least squares algorithm, preventing the overflow of the discharge grid of weight coefficients of an adaptive transverse filter and guaranteeing stable system operation, is suggested for the tuning of an adaptive system of an actively quenched sound field. Experimental results are provided for an adaptive filter with a modified algorithm in a system of several harmonic components of an actively quenched sound field.Nizhegorod State University. Translated from Izvestiya Vyssikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 10, pp. 1262–1272, October 1994. 相似文献