相移

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。

It can get the three-dimensional profile of the object surface effectively. Because of the cragginess of the three-dimensional surface when sine grating is projected the image of the sine grating is modulated and the modulated image is taken by a CCD camera with an angel compared to projecting direction. After the phase shift measuring method, the phase is gotten. Because the phase is calculated by the phase shift measuring ranges from –π to +π it isn't continuous. The phase unwrapping is necessary to recover the continuous phase about the object shape.

这种方法采用结构光照明，将正弦光栅图像投影到被测物体表面，用与投影方向成一定角度的CCD摄像机获取受物体表面面形调制的变形光栅像，根据数字相移算法计算出相位分布，由于从相移计算的相位被截断在反三角函数的主值范围内，因而是不连续的，必须通过相位展开恢复出连续相位分布，由相位－高度关系最终求出物体轮廓的三维数据信息。

From 1920s up to Now, various techniques and methods for wave field decomposition, propagation and migration/imaging have been well developed, such as the Kirchhoff asymptotic method, frequency-wavenumber domain phase-shift and phase-shift-plus-interpolation methods, and the one-way wave equation based phase-screen and generalized screen methods, etc.

自上个世纪二十年代至今，波场分解、传播与偏移成像技术经历了将近一个世纪的发展，形成了多种不同的方法，如Kirchhoff波动方程高频近似解方法，频率-波数域的相移(phase-shift)方法和相移-内插方法，以及在混合域中基于单向波动方程的相位屏、广义屏方法等。

When an image digital holographic microscopy layout is employed, the Fresnel integral cannot be used in separating the reconstructed image from its conjugate image and background.

在像面数字全息中，用菲涅尔衍射积分进行复振幅再现的方法已不适用，将相移同轴技术与数字全息显微术结合，研究了以平行光为参考光记录相移同轴像面显微数字全息图及其幅度和相位再现方法。

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。

To complex the earth's surface with written software the real data of the area undertook trying calculating, processing makes clear as a result, with " phase shift - when move law " has fluctuant equation datum plane corrective can eliminate well rise and fall the influence that the earth's surface and logarithm of complex and upper structure occupy, for speed analysis and inphase overlay lay good foundation.

用编写的软件对复杂地表区的实际资料进行了试算，处理结果表明，用"相移-时移法"进行波动方程基准面校正能很好地消除起伏地表和复杂地表结构对数据的影响，为速度分析和同相叠加奠定良好的基础。

In chapter 3, the principle and method of Phase-Shifting Digital Speckle Pattern Interferometry are studied.

第三章讨论了相移数字散斑干涉计量技术的原理和方法，并对相移求解方法及精度进行了详细的讨论。

The two-mode fiber acoustic-optic nonreciprocal phase shifter consists of twoacoustic-optic frequency shifters same in characteristic and mode strippers, etc. Socharacteristic of the acoustic-optic frequency shifter and the identification of twoacoustic-optic frequency shifters' characteristics are very important.

双模光纤声光非互易相移器由两个性能一致的声光移频器及模式剥离器等构成，因此声光移频器本身的性能如何以及两个声光移频器的性能是否一致非常关键。

This approach has the advantages of simple circuit, accurate detection and good robustness. Two kinds of topologies in Active Power Filter have been proposed, including APF based on cascade converter with phase-shifted SPWM technique and APF based on current source multimodular converter with phase-shifted SPWM technique.

本文提出了两种基于相移SPWM技术的并联型有源电力滤波器的拓扑结构：基于相移SPWM级联型变流器的电压源型APF，基于电流型相移SPWM组合变流器的电流源型APF。

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。