计算机控制光学表面成型技术综述

介绍了计算机控制光学表面成型技术的原理基础，目前的进展及其将来的趋势。主要介绍美国、法国、俄罗斯的科学家在这项技术上的成果，也简单介绍了我国在这一领域的研究工作。最后提出了目前还存在的问题。     

计算机控制光学表面成形驻留时间算法研究

光学非球面的使用可以提高光学系统的性能、简化系统结构、减小系统体积,减轻系统重量,计算机控制光学表面成形（ＣＣＯＳ）方法是加工光学非球面的重要方法。介绍了ＣＣＯＳ原理,给出了ＣＣＯＳ中关键技术驻留时间计算的三种算法———基于加工仿真的算法、基于傅立叶变换的算法和基于滑动平均与傅立叶变换的算法。基于加工仿真的驻留时间算法需要做大量的卷积计算,计算时间较长,残余误差较大;基于傅立叶变换的驻留时间算法与基于滑动平均和傅立叶变换的驻留时间算法计算时间短,计算后的残余误差小。磨头单位去除函数形状与磨头大小对误差的去除也有明显的影响,小的磨头和陡峭的单位去除函数对于去除局部误差更为有利,但是加工时间较长     

计算机控制光学表面成形中大规模驻留时间求解

采用基于稀疏矩阵的大规模非负最小二乘法,对大口径、微浮雕结构光学元件加工中的驻留时间进行了分析与求解,并对该算法开展了正则化研究。仿真结果表明:与传统非负最小二乘法相比,基于稀疏矩阵的大规模非负最小二乘法精度高、效率快。采用该算法仿真加工平均振幅为1.177 6倍波长的大口径、微浮雕结构光学元件,误差面形均方根收敛至0.067倍波长。     

计算机控制光学表面成形法初值的确定

介绍了计算机控制光学表面成形法的原理,分析了几种非球面度的测量方法,研究了非球面度的不同计算方法对采用计算机控制光学表面成形法加工非球面的影响。从光学零件加工的角度对计算机控制光学表面成形法初值的确定进行了探讨。     

Study of weighted space deconvolution algorithm in computer controlled optical surfacing formation

Theoretical and experimental research on the deconvolution algorithm of dwell time in the technology of computer controlled optical surfacing （CCOS） formation is made to get an ultra-smooth surface of space optical element. Based on the Preston equation, the convolution model of CCOS is deduced. Considering the morbidity problem of deconvolution algorithm and the actual situation of CCOS technology, the weighting spatial deconvolution algorithm is presented based on the non-periodic matrix model, which avoids solving morbidity resulting from the noise induced by measurement error. The discrete convolution equation is solved using conjugate gradient iterative method and the workload of iterative calculation in spatial domain is reduced effectively. Considering the edge effect of convolution algorithm, the method adopts a marginal factor to control the edge precision and attains a good effect. The simulated processing test shows that the convergence ratio of processed surface shape error reaches 80%. This algorithm is further verified through an experiment on a numerical control bonnet polishing machine, and an ultra- smooth glass surface with the root-mean-square （RMS） error of 0.0088 tim is achieved. The simulation and experimental results indicate that this algorithm is steady, convergent, and precise, and it can satisfy the solving requirement of actual dwell time.     

非球面聚焦透镜数控加工技术研究

 国内现有的高功率固体激光装置所使用的非球面聚焦透镜都是用传统方式手工加工而成的，由于手工加工方式的加工精度和进度对人的依赖性很大，势必影响大批量制造时的工程进度。而采用新兴的小磨头数控加工技术则可以避免这些缺点。介绍了首次将小磨头数控加工技术用于非球面聚焦透镜的加工，对其中各项技术，包括典型靶镜参数、机床控制方式、加工运动方式、实验使用参数、检测方式进行了分析，并得到了预期的实验结果。     

计算机控制光学抛光驻留时间求解中两类优化算法的分析

建立了基于矩阵计算的驻留时间计算模型,根据实际加工要求建立了最小二乘和最佳一致逼近最优化求解数学模型,总结了两类优化问题的求解方法。根据自研数学解法器,利用数值计算分析了这两类算法的计算特点。仿真结果显示,两种自研算法具有较高的计算精度,最小二乘逼近算法计算效率有待提高,对外界扰动和计算模型等误差不敏感,最佳一致逼近算法计算效率较高,但对误差比较敏感。实际加工时,如果面形精度已经比较高时,建议多采用最小二乘逼近算法。     

计算机控制非球面加工精磨阶段的检测技术

讨论了计算机控制非球面加工（ＣＣＯＳ）过程中精磨阶段的面形误差数字化技术。提出了线性插值法代替惯用的泽尼克多项式拟合用于表面的精磨。并给出应用实例，验证了该方法的有效性。     

Signal formats and error correction in optical transmission

We review the advantages and drawbacks of the main optical modulation formats, comparing the standard intensity-modulated ones to more sophisticated phase and intensity modulated formats for high capacity or long distance transmission. Furthermore, different Forward Error Correction solutions, from standard Reed Solomon (RS) to block turbo codes, are presented and their impact on optical transmission system design is discussed. To cite this article: O. Ait Sab, H. Bissessur, C. R. Physique 4 (2003).     

A computer controlled time resolved optical intensity profile measurement system

In this paper, a computer controlled system is described, which provides data management and position control for time resolved measurement of near and far field, along with charge carrier concentration distributions of semiconductor lasers. Of particular interest is the manner in which microprocessor control of inexpensive motorised micrometers is used to provide accurate repeatable movements on submicron scales. Due to its noise reduction capability through computer averaging, this system has been operated in conjunction with a 50 ps risetime photodiode, and thus is believed to allow time resolved measurement on the shortest reported timescales. The system provides a further advantage in that experimental data may be stored to give easy access for further processing.     

自由曲面透镜误差修正加工控制的算法

自由曲面玻璃透镜的误差修正控制算法是一个新的领域。本文借鉴了在数字图像处理中的一些方法 ,探讨了它的修正算法 ,其中包括傅立叶变换算法、维纳滤波算法和直接算法等 ,并进行了计算机仿真。结果表明 :维纳滤波算法效果较好。最后对在工程实际中应该注意的问题进行了讨论。     

The method to evaluate the position error in graphic positioning technology

In the measurement of automobile body-in-white, it has been widely studied to position the two dimensional(2D)visual sensors with high precision. In this paper a graphic positioning method is proposed,a hollow tetrahedron is used for a positioning target to replace all the edges of a standard automobile body.A 2D visual sensor can be positioned through adjusting two triangles to be superposed on a screen of the computer, so it is very important to evaluate the superposition precision of the two triangles. Several methods are discussed and the least square method is adopted at last, it makes the adjustment more easy and intuitive with high precision.     

平面元件数控加工技术研究

利用从俄罗斯引进的ＡＤ １０００ 数控研磨抛光机对Φ３３０ｍｍ ×３５ｍ ｍ 、２３０ｍ ｍ ×２３０ｍ ｍ ×４０ｍ ｍ 两块Ｋ９材料平面光学元件进行计算机控制抛光工艺研究。通过工艺研究全面熟悉了设备的技术特性和工艺软件特性,验证了ＡＤ １０００ 数控研磨抛光机在加工高精度光学元件基板方面Ｐ Ｖ、ＲＭＳ值收敛效果明显,较传统加工方法在效率上有极大提高。     

All linear optical quantum memory based on quantum error correction

When photons are sent through a fiber as part of a quantum communication protocol, the error that is most difficult to correct is photon loss. Here we propose and analyze a two-to-four qubit encoding scheme, which can recover the loss of one qubit in the transmission. This device acts as a repeater, when it is placed in series to cover a distance larger than the attenuation length of the fiber, and it acts as an optical quantum memory, when it is inserted in a fiber loop. We call this dual-purpose device a "quantum transponder."     

一种对流层折射误差的实时简化修正方法

对流层折射误差是影响雷达测量定位系统精度的主要因素之一。针对VMF1(Vienna Mapping Function 1)用于对流层折射误差修正时存在的实时性差、分辨率低的问题,引入GPT2w模型并提供分辨率为1°×1°的相关参数,结合Saastamoinen模型构建形成SG-VMF1模型。基于新模型和映射函数法的计算原理,对4个IGS(International GNSS Service)测站在不同高度角时的对流层折射误差进行估算,并与射线描迹法的计算结果进行对比分析。结果显示：以结合IGS实测气象数据的射线描迹法的计算结果为基准时,利用SG-VMF1模型及相关理论计算的结果在高度角大于6°时RMS值可达到0.4 m,在高度角大于30°时RMS值可达到0.1 m,计算方法可行有效,且具有实时性和较高的分辨率。     

Minimum mean square error method for stripe nonuniformity correction

Stripe nonuniformity is very typical in line infrared focal plane (IRFPA) and uncooled starring IRFPA. We develop the minimum mean square error (MMSE) method for stripe nonuniformity correction (NUC). The goal of the MMSE method is to determine the optimal NUC parameters for making the corrected image the closest to the ideal image. Moreover, this method can be achieved in one frame, making it more competitive than other scene-based NUC algorithms. We also demonstrate the calibration results of our algorithm using real and virtual infrared image sequences. The experiments verify the positive effect of our algorithm.     

数控抛光技术中抛光盘的去除函数

抛光盘去除函数的确定是数控抛光技术的应用基础,以Ｐｒｅｓｔｏｎ 方程为基础,应用运动学原理推导了抛光盘在行星运动及平转动两种运动方式下的材料去除函数,并通过计算机模拟出相应的工作特性曲线。结果表明,两种运动方式下工作特性曲线均在不同程度上趋近于高斯曲线。因而行星运动及平转动都可作为抛光盘的运动方式应用在ＣＣＯＰ技术中,使加工中的面形误差得到收敛。     

Limits to error correction in quantum chaos

We study the correction of errors that have accumulated in an entangled state of spins as a result of unknown local variations in the Zeeman energy ( B) and spin-spin interaction energy ( J). A nondegenerate code with error rate kappa can recover the original state with high fidelity within a time t(R) approximately Planck's over 2pikappa(1/2)/max(B,J)-independent of the number of encoded qubits. Whether the Hamiltonian is chaotic or not does not affect this time scale, but it does affect the complexity of the error-correcting code.     

Runout error correction in tomographic reconstruction by intensity summation method

An alignment method for correction of the axial and radial runout errors of the rotation stage in X‐ray phase‐contrast computed tomography has been developed. Only intensity information was used, without extra hardware or complicated calculation. Notably, the method, as demonstrated herein, can utilize the halo artifact to determine displacement.     

计算全息法标定单光楔补偿检测系统误差

单光楔补偿检测法具有良好的适用性、鲁棒性和灵活性,但是在检测光路中存在多种误差耦合,误差解耦困难,影响了单光楔补偿检测的精度和可信度.针对这一问题,本文提出一种计算全息法(Computer Generation Hologram,CGH)标定单光楔补偿检测光路系统误差的新方法.文中首先分析了单光楔补偿检测法系统误差的来...