查询词典 phase shifting

This technique uses a spiral phase plate with a small central aperture placed on the Fourier plane of so imaging system. If the spiral phase filter is rotated by a certain angle around its central axis, a phase shift between the zero-order spatial frequency component and the remaining of the object is produced, and the magnitude of this phase shift is proportional to the rotation angle. Using this property, we can record a sequence of intensity distribution of the output beams corresponding to different rotation angles, and then digitally reconstruct the objects by using a phase-shifting algorithm. Both the theoretical analysis and simulation experiment results demonstrate the feasibility of this approach.

在成像系统的频谱面上放置中心带有一通光孔径的螺旋相位板，在输出面上记录输入物体经螺旋相位滤波后的输出像；将螺旋相位滤波器绕轴旋转一定角度，通过中心光孔的零频成份与其他高频成份间会产生与旋转角度成正比的相移；利用这一特点，通过记录多幅对应不同旋转角度的输出光场强度分布图，然后再用一定的相移算法实现被记录物体相位分布的数字再现。

This technique uses a spiral phase plate with a small central aperture placed on the Fourier plane of an imaging system. If the spiral phase filter is rotated by a certain angle around its central axis,a phase shift between the zero-order spatial frequency component and the remaining of the object is produced,and the magnitude of this phase Shift is proportional to the rotation angle. Using this property,we can record a sequence of intensity distribution of the output beams corresponding to different rotation angles,and then digitally reconstruct the objects by using a phase-shifting algorithm. Both the theoretical analysis and simulation experiment results demonstrate the feasibility of this approach.

在成像系统的频谱面上放置中心带有一通光孔径的螺旋相位板，在输出面上记录输入物体经螺旋相位滤波后的输出像；将螺旋相位滤波器绕轴旋转一定角度，通过中心光孔的零频成份与其他高频成份间会产生与旋转角度成正比的相移；利用这一特点，通过记录多幅对应不同旋转角度的输出光场强度分布图，然后再用一定的相移算法实现被记录物体相位分布的数字再现。

The measurement error of phase shifting method is calculated.It is concluded that if 5 frames are used per time, in order to achieve 0.3° precision inphase measurement, phase shifting error must be limited in± 0.1° plus at least 60dBsignal to noise ratio.

同时，还进行了相移检测法的初步误差分析和模拟研究，结果表明：采用5幅图像的方法，要实现0.3°的检相精度，就要求相移误差在±0.1°以内，信噪比为60dB以上。

The main purpose of this paper is to improvement of isochromatics wrapped phase map can make the phase to unwrap successfully and get the physical quantity we want to know. There is a peculiar problem of isochromatic interaction in Phase-shifting techniques of photoelasticity.

中文摘要本论文主要的目的是利用负载相移法来求得相位图，并且使用相位展开的技术使相位图展开完成，得到我们所要求得的物理量-相对延迟量。

We expect it will benefit the industry field to break through the optical measuring limits at present by offering some new ideas. Optical measuring research based on moire interferometry has developed for several decades. The main idea of this research is to utilize the moire effect caused by two superimposed gratings of identical or similar spatial frequency. One is the reference grating and it is a virtual grating created by a computer program in this research; The other grating is the image of grating projected on the measured surface by the DLP projector, and this grating will distort because of the different sloped profile of the surface. To superimpose the program-created grating and the captured distorted grating will derive the so-called moire effect. This research combined the basic theory of optical interferometry and moire effect to project the different phases of the projected grating fringes by the phase-shifting method and compute the principal value of arguments between -π,π. In the end, the phase unwrapping program based on discrete Fourier transform of solving PDEs is used to unwrap the phase of the measured surface, and finally the surface profile is derived by the optical measuring system.

以叠纹干涉术为基础的光学检测研究之发展早已行之有年，而在本研究中所采用的投影叠纹法(Projection moiré)之主要精神在於藉由两道空间频率相近或相同的光栅相互叠加而成的效应，其中一道为参考光栅，而本研究中的参考光栅是以程式产生可调整不同空间频率的虚拟光栅；另一道则为投影至待测物表面的光栅影像，而在起伏高度不一的待测表面上的光栅影像会受到待测物表面起伏状况不同而在观测方向产生光栅投影条纹影像的歪曲变形，将电脑产生的参考光栅与由影像撷取装置所获取投影於待测物表面的光栅影像作叠合，便会产生所谓的叠纹效应；利用基本的光学干涉理论与叠纹效应结合，本研究中以相移法来改变投影於待测表面的光栅相位，再以相移法的理论反运算出在带有待测面各点高度资讯之介於-π，π相位主幅角，再以离散傅立叶转换解偏微分方程的相位重建程式还原待测面的相位值，以得知待测面之表面轮廓。

In phase calculate of phase-shifting interference technique,Because of the periodicity of function arctan,all the phase values are ranged over-π to π.

在移相干涉技术的相位计算中，周期函数arctan的相位值分布在之间，相位值分布的跃变形成了被压包后的波面。

Considering strict and complex phase requirement, phase locked loop was used for precise phase shifting. Through Embedded logic analyzer the timing was sampled and verified. The driving timing generator of CCD camera with adjustable integral time was implemented on the CCD circuit board.Frame transfer CCD; Integral time ; Phase locked loop ; Embedded logic analyzer

考虑到CCD驱动时序复杂、相位要求严格，提出运用锁相环技术进行高频信号的精确移相，用嵌入式逻辑分析仪对时序进行采样验证，在CCD电路板上实现了积分时间可调的CCD空间相机驱动时序。

According to this method,four different 11-step algorithms with four different window functions which are rectangular window,triangle window,hanning window,and blackman window are designed. Analysis and simulation show that hanning window and blackman window with small lobes are less sensitive to errors. Seven different algorithms with the same phase shifting interval π/2 are designed by hanning window function,whose phase shifting steps are separately 5,11,15,39,51,76 and 101 steps.

选择矩形窗、三角窗、hanning窗和blackman窗生成4种11步移相算法，对振动误差和相移误差的分析验证了旁瓣小的hanning窗和blackman窗生成的算法对误差的灵敏度要小；再选择hanning窗生成了移相间距为π/2的5，11，15，39，51，76和101步7种移相算法，仿真验证了步数越多主瓣越小，对振动抑制能力越好，但需要更高的微位移器移动精度来获得有效的干涉条纹。

To realize automatic measuring of this method and improve it's precision, in this thesis the liquid crystal cell is used as a phase-shifter for the traditional DSSPI successfully. The phase-shifting DSSPI system is designed based on the liquid crystal phase-shifter and Wollaston prism.

为了进一步实现该方法的自动化检测，提高测试精度，在本论文中，成功的把液晶体做相移器应用于传统的数字错位散斑干涉计量，设计了基于液晶相移器和渥拉斯顿棱镜的数字错位散斑干涉系统。

By demonstrating the feasibility of time stepping quadrature phase shifting method, we successfully remove the phase shifting device from the system and basically eliminated the errors induced by the inaccurate phase modulation.

在演算法方面，藉由证实时进正交相移法之可行性，将光路中的相移装置移除，终於使得因为相位调制方法不精准所造成的误差得到彻底的改善。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。