1 浙江大学现代光学仪器国家重点实验室国家光学仪器工程技术研究中心, 浙江 杭州 310027
2 浙江大学台州研究院, 浙江 台州 318000
离焦抖动优化技术不仅能消除投影仪的非线性误差,而且不受投影仪刷新率的限制。然而抖动算法本质上只是一个简单的矩阵变换,导致离焦后的二值抖动条纹并不完全接近正弦条纹,产生了一定的测量误差。基于此,提出了一种基于离散粒子群算法的优化方法,对二值离焦抖动技术进行优化。为了加快优化过程,用二值块的优化来代替整个二值图案的优化,然后再利用正弦条纹图案的周期性和对称性,将二值块拼成一个完整的图案。仿真和实验结果表明:所提方法在不同的离焦程度下,都能获得高质量的测量结果。
测量 三维图像获取 二值图像 粒子群优化 抖动 中国激光
2019, 46(10): 1004003
1 浙江大学现代光学仪器国家重点实验室国家光学仪器工程技术研究中心，浙江 杭州 310027
2 浙江大学台州研究院，浙江台州 318000
3 浙江大学现代光学仪器国家重点实验室国家光学仪器工程技术 研究中心，浙江 杭州 310027
现阶段通用的相机标定方法需要使用者提供准确的标定板特征点像素坐标。但对某些成像位置特殊的相机而言，一般标定物(如长宽在厘米级别的标定板)的使用范围在其清晰成像范围之外。使用这些相机拍摄一般标定物，只能得到离焦的模糊图像，无法准确提取特征点像素坐标。本文分析了光学系统离焦状态对基于正弦光栅的结构光(简称正弦结构光)相位的影响。利用正弦结构光相位与相机对焦状态无关的性质，提出了一种利用相移法正弦结构光编码的方法，对标定物上特征点进行相位编码，实现了相机在离焦状态下的标定。经过实验验证，标定结果焦距长度与真实值之间最大偏差为0.47%，最大像素重投影误差为0.17 pixels。该方法为具有特殊成像范围的相机的标定提供了一种解决方案。
相机标定 对焦 相位匹配 相移法 摄影设备 calibration focusing phase matching phase shift photographic equipment
Author Affiliations
Abstract
1 CNERC for Optical Instruments, Zhejiang University, Hangzhou 310027, China
2 State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China
3 Public Security Department of Zhejiang Province, Hangzhou 310007, China
This Letter proposes a brand-new filament diameter measurement method based on what is called “dual diffraction,” in that a grating is added behind the filament to make full use of its subdivision and amplification characteristics. Higher measurement accuracy is achieved by this method compared with the traditional diffraction method. To verify its accuracy, three standard filaments with nominal values of 100.2, 120.1, and 140.8 μm are measured by the dual diffraction method and traditional diffraction method under the same experimental conditions. The relative measurement errors of the new method are less than 0.75%, and its average relative error is reduced by 56% compared with the traditional diffraction method.
050.1940 Diffraction 050.2770 Gratings 120.4820 Optical systems Chinese Optics Letters
2015, 13(12): 120501
浙江大学现代光学仪器国家重点实验室，国家光学仪器工程技术研究中心, 浙江 杭州 310027
提出一种将三角法测距与多频光栅相结合的方法，充分利用数字投影的RGB通道，将多频光栅与点阵同时投影在物体表面，综合控制受高度调制的相位信息的提取，最终获取物体的三维形貌。仿真结果显示，在高度跳变使高频光栅位移达102量级个周期时，可以准确还原原始形貌。通过实验验证，本方法能够同时复原169 mm的陡峭高度跳变以及3 mm的微小细节，提高了传统双频光栅的性能，具有处理较大截断面和保证细节部分的测量能力，较好地改善了傅里叶变换轮廓术(FTP)的应用性能。
测量 傅里叶变换轮廓术 点阵和多频光栅结合 大截断面测量
Author Affiliations
Abstract
The features of Moire fringe generated by overlapping a circular and a linear grating are studied. Given that the pitch of circular grating is a and that of linear grating is P, the shapes of the Moire fringe that they form are hyperbola, parabola, and ellipse when a > P, a = P, and a < P, respectively. As the pitches of these two gratings become close to each other, the magnification of the Moire fringe is over 100, which is useful for the measurement of small displacement. This letter also discusses how the fill factor influences Moire fringe visibility.
050.2770 Gratings Chinese Optics Letters
2011, 9(s1): s10702
Author Affiliations
Abstract
State Key Laboratory of Modern Optical Instrumentation, CNERC for Optical Instrument, Zhejiang University, Hangzhou 310027
We propose a new subdivision technique directly subdividing the grating stripe by using complementary metal-oxide semiconductor (CMOS) microscopic imaging system combined with image processing. The corresponding optical system, subdivision principle, and image processing methods are illuminated. The relations of systemic resolution to subdivision number, grating period, magnifying power and tilt angle are theoretically discussed and experimentally checked on the Abbe comparator. The measurement precision for displacement of the proposed subdivision system is tested in the range of 5 mm and the maximum displacement error is less than 0.4 micron. The factors contributing to the systemic error are also discussed.
光栅 细分 CMOS显微成像 图像处理 测量精度 120.3930 Metrological instrumentation 050.2770 Gratings 110.2960 Image analysis Chinese Optics Letters
2007, 5(5): 278
1 浙江大学现代光学仪器国家重点实验室 浙江大学国家光学仪器工程技术研究中心，杭州 310027
2 星星集团浙江水晶光电科技有限公司，浙江台州 318015
光电成像系统的抽样过程会引起图像频谱在频谱空间上的多次复制，如果抽样过程不满足系统的奈奎斯特条件，相邻的频谱项就会产生混叠．光学传递函数可以反映系统中光学成像，抽样和重建等各个过程对图像信号频谱的响应．通过对使用光学低通滤波器(OLPF)光电成像系统的光学传递函数的分析，表明光学低通滤波器可以有效地限制图像的频谱宽度，使抽样满足奈奎斯特条件，达到消除频谱混叠，改善重建图像质量的目的．
光学传递函数 光学低通滤波器 奈奎斯特准则 频谱混叠 Optical transfer function Optic low-pass filter Nyquist criterion Aliasing
1 浙江大学现代光学仪器国家重点实验室浙江大学国家光学仪器工程技术研究中心，杭州 310027
2 安徽师范大学物理与电子信息学院，芜湖 241000
3 浙江大学光电信息工程学系，杭州 310027
应用电路模拟软件Multisim对四边形结构、方形结构、直角形结构、双面结构位置敏感探测器的线性度进行仿真实验研究，得到了相应的线性网格图，并进行了分析．综合比较这几种不同结构二维位置敏感探测器的线性度．结果表明：四边形电极结构位置敏感探测器的位置误差最大，中央40%光敏区的位置误差约为10．05%，直角型电极结构位置敏感探测器，双面型电极结构位置敏感探测器以及带电阻边框的方形电极结构位置敏感探测器在相应区域的位置误差的误差分别为3．70%，0．29%，0．12%．对计算结果与试验结果进行了比较，表明该方法具有简单直观，参量变化多样性，结果可靠的优点．
位置敏感探测器 非线性 位置误差 Position sensitive detector Multisim Multisim Non-linearity Position error
Author Affiliations
Abstract
CNERC for Optical Instrument, Zhejiang University, Hangzhou 310027
A new interpolating method to enhance the resolution of gratings using complementary metal-oxide semiconductor (CMOS) according to the variation of some specified spectral light intensities during the motion of scale grating in a periodic separation is proposed. CMOS image sensor (pixel array 648*488) was also introduced as receiving device and its stability was verified experimentally. Many factors in the experiment were analyzed theoretically and contrasted with experiment. The advantages of this novel method were featured by CMOS and the specified spectral variation of the energy distribution was discussed.
120.6200 spectrometers and spectroscopic instrumentation 050.1950 diffraction gratings 300.6170 spectra 110.0110 imaging systems Chinese Optics Letters
2005, 3(2): 0280
本文提出一种光闸条纹的轮廓推算法,同日本人提出的方法相比,此法简单而且概念明确。文中采用两种方法来验证推算法的正确性,即将常用的计算法计算的及实测的轮廓数值和推算的轮廓数进行比较,结果颇为满意。
莫尔花样 光栅 光学测试
