共查询到19条相似文献,搜索用时 140 毫秒
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基于脉动阵列的自适应光学实时波前处理机设计 总被引:1,自引:0,他引:1
针对自适应光学系统对波前处理机高计算量、高实时性的要求,本文提出了一种基于脉动阵列的自适应光学实时波前处理方法.该方法将脉动阵列的概念引入波前处理机设计,完成了波前斜率计算、复原运算和控制运算向脉动阵列的映射,合理地建立了数据的深度流水线,同时分析了以FPGA技术实现时系统的计算延时.对于48个子孔径,61单元的自适应光学系统,以一片Xilinx Virex-Ⅱ XC2V3000芯片实现了基于脉动阵列的实时波前处理机,实验测得计算延时仅8.6μs,结果表明该方法能极大地提高系统的实时性,集成度、通用性和扩展性. 相似文献
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直接斜率波前复原算法的控制效果分析 总被引:7,自引:0,他引:7
建立自适应光学系统功率谱抑制函数的概念,分析了采用直接斜率波前复原算法的自适应当光学系统的控制效果,理论分析与61单元自适应光学系统上的实验结果表明,直接斜率波前复原算法将导致控制效果下降。 相似文献
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从斜率复原波前是夏克-哈特曼波前传感器这一类斜率采样探测器的核心流程。传统的复原算法中,区域法对局部波前的复原效果好,但易受斜率噪声的影响,同时空间分辨率较低;模式法抗噪能力强,但没有精确复原局部波前的能力。本文提出了基于B样条函数的快速复原算法,将波前展开为B样条曲面的线性组合,并将复原问题从斜率最小二乘问题转化为泊松方程,利用斜率的Taylor展开式估计散度,再通过超松驰迭代法进行快速求解。该方法将B样条函数的理论散度积分和实际散度估计分离,可以方便地扩展到不同阶次和不同节点数量的B样条基复原算法中。另外,通过改变散度估计的计算区域,可以灵活控制并平衡算法的局部复原能力和抗噪能力。对变形镜驱动器响应函数的测量实验表明,该方法具有较好的局部复原能力、抗噪能力和任意精度的空间分辨率。 相似文献
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针对云南天文台1.2m望远镜上的61单元高分辨率自自应光学系统,进行了微光工作环境下波前传感器子孔径数和信标亮度匹配的实验研究。在Hartmann-Shack波前传感器前的平行光路加入一个变倍光学系统,进行了8*8、6*6、4*4和2*2子孔径阵列在不同信标亮下波前感器对波前的探测实验。 相似文献
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37单元自适应光学系统 总被引:1,自引:0,他引:1
报道了在我们的大气传输及自适应光学校正实验室内建立的一套37单元自适应光学系统的原理和特点。文中给出系统实验框图、一个基于SVD上的算法分析、系统控制算法和一些实验结果。 相似文献
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37单元自适应光学系统实时波前处理 总被引:1,自引:0,他引:1
讨论了37单元自适应光学系统中子孔径排布、CCD相机的图象输出方式及波前处理算法的特点,并介绍了针对系统中帧频为380/秒的波前探测器研制的用5片TMS320C25并行处理的、峰值运算速度达1亿次/秒的高速数字处理器-波前处理机的原理和实现。该机对一帧图象的采集和处理延时为3.4ms。 相似文献
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Wave-front sensing by use of a Green's function solution to the intensity transport equation 总被引:3,自引:0,他引:3
Woods SC Greenaway AH 《Journal of the Optical Society of America. A, Optics, image science, and vision》2003,20(3):508-512
A method for reconstructing an unknown wave front from measurements of its intensity distribution on two planes along the direction of propagation is described. The method solves the intensity transport equation by use of Neumann boundary conditions, leading to a solution that requires only matrix multiplication. The method provides real-time wave-front reconstruction with high accuracy and is easily reposed to permit reconstruction of the wave front in any orthonormal basis set. 相似文献
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Aksenov VP Tikhomirova OV 《Journal of the Optical Society of America. A, Optics, image science, and vision》2002,19(2):345-355
Analytical expressions are derived and computational algorithms are constructed for retrieving optical-field phase distribution under strong scintillation. The input data for the phase reconstruction are the wave-front slopes registered by a Hartmann sensor or shearing interferometer. The theory is based on representing the slope-vector field as the sum of its potential and solenoid components; it introduces the concept of phase-source and phase-vortex density and uses strict integral expressions relating these quantities to the wave-front slopes. To overcome the difficulties arising from the singular character of phase distribution, use is made of regularization of the wave-front slopes. The slopes can be measured with an ideal point wave-front sensor. It is shown that the slopes measured at the output of a nonideal sensor can be treated as regularized values of these slopes. Numerical simulation of phase unwrapping from the reference values of the wave-front slopes has shown that the algorithm designed for visualization of local phase singularities and those for phase reconstruction are very helpful in eliminating the measurement noise. 相似文献
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Bará S 《Journal of the Optical Society of America. A, Optics, image science, and vision》2003,20(12):2237-2245
A usual approximation in Hartmann-Shack aberrometry is that the centroid displacements are proportional to the spatial averages of the wave-front slopes at the sampling subapertures. However, these spatial averages are actually weighted by the local irradiance distribution across each microlens. The irradiance across the eye pupil is not uniform in usual reflectometric aberrometers, which is due to several factors including retinal scattering and cone waveguiding directionality. It is shown that neglecting this fact in usual least-squares reconstruction procedures gives rise to a biased estimation of the aberration coefficients. The magnitude of this bias depends on the actual irradiance distribution across the eye pupil, the mode being estimated, the detailed modal composition of the aberrated wave front, and the geometry of the wave-front sampling array. Order-of-magnitude calculations suggest that this bias may well be in the range 5%-10% for relatively smooth irradiance distributions. The systematic nature of this error makes it advisable to check for its presence and, if required, to compensate for it by an adequate choice of the least-squares reconstruction matrix. 相似文献
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Justh EW Vorontsov MA Carhart GW Beresnev LA Krishnaprasad PS 《Journal of the Optical Society of America. A, Optics, image science, and vision》2001,18(6):1300-1311
A wave-front control paradigm based on gradient-flow optimization is analyzed. In adaptive systems with gradient-flow dynamics, the output of the wave-front sensor is used to directly control high-resolution wavefront correctors without the need for wave-front phase reconstruction (direct-control systems). Here, adaptive direct-control systems with advanced phase-contrast wave-front sensors are analyzed theoretically, through numerical simulations, and experimentally. Adaptive system performance is studied for atmospheric-turbulence-induced phase distortions in the presence of input field intensity scintillations. The results demonstrate the effectiveness of this approach for high-resolution adaptive optics. 相似文献
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We describe a novel wave-front sensor comprising a distorted diffraction grating, simple optics, and a single camera. A noniterative phase-diversity algorithm is used for wave-front reconstruction. The sensor concept and practical implementation are described in detail, and performance is validated against different Zernike modes and a representative atmospheric phase map. 相似文献
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A high-aspect-ratio line focus is required on a plane target in x-ray laser experiments for obtaining a high gain-length product. Inherent wave-front aberrations in line-focusing optics, which consist of a cylindrical lens and a spherical lens, are discussed with respect to beam diameter. The nonuniformity of the linewidth that is due to the aberrations is also calculated by the ABCD matrix method. A deformable mirror of a continuous plate type with a diameter of 185 mm provides an adequate wave-front distribution for compensating for the wave-front aberration. The wave-front control by the deformable mirror realizes a fine linewidth of 25 mum and 18.2 mm long, corresponding to the aspect ratio of 728. The linewidth is three times the diffraction limit. The intensity distribution along the line focus is also improved. 相似文献
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Goldberg KA Geary K 《Journal of the Optical Society of America. A, Optics, image science, and vision》2001,18(9):2146-2152
In interferometry and optical testing, system wave-front measurements that are analyzed on a restricted subdomain of the full pupil can include predictable systematic errors. In nearly all cases, the measured rms wave-front error and the magnitudes of the individual aberration polynomial coefficients underestimate the wave-front error magnitudes present in the full-pupil domain. We present an analytic method to determine the relationships between the coefficients of aberration polynomials defined on the full-pupil domain and those defined on a restricted concentric subdomain. In this way, systematic wave-front measurement errors introduced by subregion selection are investigated. Using vector and matrix representations for the wave-front aberration coefficients, we generalize the method to the study of arbitrary input wave fronts and subdomain sizes. While wave-front measurements on a restricted subdomain are insufficient for predicting the wave front of the full-pupil domain, studying the relationship between known full-pupil wave fronts and subdomain wave fronts allows us to set subdomain size limits for arbitrary measurement fidelity. 相似文献