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本文提出了一种利用补偿原理直接测量压电换能器串联谐振频率fs和并联谐振频率fP的新方法一补偿法。在这种方法测量原理的基础上,进行了实际测量,并设计了一种实用的测量电路。采用此方法测量的测量结果与电桥法的结果相符得很好。 相似文献
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本文提出了一种新的耦合损耗因子测量方法:声强法。声强法利用结构声强技术测量的耦合处功率流计算耦会损耗因子。严格地说,声强法是一种近似测量方法。本文以三种常见的典型耦合结构为例,实验证明了在大多数情况下,声强法的近似误差很小,可以略去不计;声强法测量的耦合损耗因子与传统的能级差法测量的耦合损耗因子是“相等”的,它们都具有“相同”的测量精度。声强法与能级差法是“等效”的耦会损耗因子测量方法。 相似文献
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应用CCD的透镜曲率自动测量系统 总被引:6,自引:2,他引:4
本文介绍了一种以线阵CCD固态图像传感器取代读数显微镜,能自动测量和实时显示结果的透镜曲率测量系统,论述了系统的工作原理、软件和硬件的设计及装置的测量误差。 相似文献
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在热压缩态中测量相位算符的涨落 总被引:1,自引:1,他引:0
利用热场动力学的方法计算了热压缩态中测量相位算符的涨落,引入了两种类型的基础量子涨落,一种是与测量相位的两个正交分量相联系,另一种是与一个测量相位分量和光子数相联系。由此,研究了热压缩压中测量相位涨落的两种压缩及其与温度的关系。 相似文献
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在使用温度脉动仪测量温度结构常数时,平均时间长度的选择会影响其测量结果。通过实际测量数据的分析和讨论,确定平均时间应该为10s左右,以得到真实可靠的结构常数。由于温度脉动仪在测量时会受到各种因素的影响,为了筛选掉不可靠的测量结果,提出了一种用温度脉动原始数据来对测量结果进行筛选的方法。该方法首先排除了实验纪录中的错误测量数据,其次对于异常的实验数据,如某一层结构常数数据的异常偏大或偏小,需要根据双点温差原始数据的频谱分析来确认数据是否正常,以进一步排除异常的测量结果,尽可能保证用以统计分析的数据真实可靠。 相似文献
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A novel optical edge-projection method is proposed for surface contouring of an object with low reflectivity. A structured light edge is projected onto a dark surface, and the image is captured by a CCD camera. The object contour is evaluated with an active triangular projection algorithm, and one obtains a whole-field three-dimensional contour of the object by scanning the optical edge over the entire object surface. The proposed method is applied to a black nonreflective object made from woven carbon fiber and is also applied to measure the profile of a small object (a coin). The results show that an accurate profile of the specimen can be obtained. 相似文献
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次条纹积分法解调位相的三维面形测量 总被引:1,自引:1,他引:0
提出一种新的条闰相分析技术用于三维面形自动测量。将光栅图案投影于物体表面上,投影像随物体三维面形变形,形变的投影像用次条纹积分算法分析,求出位相变化和相应的三维面形。 相似文献
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Yu Fu Giancarlo Pedrini Bryan M. Hennelly Roger M. Groves Wolfgang Osten 《Optics and Lasers in Engineering》2009,47(5):552-557
A dual-wavelength image-plane digital holography, combined with a windowed Fourier analysis, is presented for dynamic measurement of a vibrating object. In order to expand the range of the velocity measurement, the object is simultaneously illuminated by two lasers with different wavelengths. A sequence of digital holograms of a vibrating object is captured by a CCD camera and two wrapped phase maps are retrieved from each digital hologram. At each instant, a new phase distribution with a synthetic wavelength is obtained by subtracting these two wrapped phase maps. A windowed Fourier analysis is then applied spatially and temporally to retrieve the high-precision displacement and velocity of the tested object. Experimental results show the requirement on the camera capture frequency is reduced by the proposed method. 相似文献
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提出一种快速实现一维粗糙地表面下方埋藏金属目标的成像算法.用层内波传播算法结合谱加速的前后向迭代算法(PILE+FB-SA)计算一维粗糙面下方埋藏金属目标的后向散射;用得到的后向散射数据结合后向投影算法实现二维SAR(synthetic aperture radar)成像,研究窗函数的选取,讨论目标位置及尺寸大小变化的影响.用具有高斯谱的粗糙面模拟实际地表面,并采用锥形波入射以减小人为截断粗糙面引起的边缘效应.由于散射数据由快速数值算法得到,该算法不受地面和目标参数限制,可以实现任意粗糙地表面和复杂目标成像,对地下目标探测具有重要的应用价值. 相似文献
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A position sensor based on grating projection with spatial filtering and polarization modulation is presented. A grating is projected onto the object to be measured through a 4f optical system with a spatial filter. After reflected by the object, the grating projection is imaged on a detection grating through an other 4f optical system to form moit(e) fringes.The polarization modulated moir(e) signal is deteted to obtain the position of object.The measurement is independent of the incident intensity on the projection grating and the reflectivity of the object to be measured. In experiments, the effectiveness of the position sensor is proved, and the root mean square (RMS) error at each measurement position is less than 13 nm. 相似文献
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It is theoretically shown that the translational wave-induced movement of a small (compared to the wavelength) object is possible
even when the time-average force on it is zero. In this case, the object moves, oscillating in the forward and backward directions.
The predominant motion of the object in a given direction is found to require the optimum choice of a carrier-wave phase with
respect to the leading edge of the wave pulses. A substantial feature of this wave transport mechanism is the possibility
of inversion of the object motion direction by merely changing the phase shift and retaining the previous direction of wave
propagation. The transport of an object under the action of pulses with various envelope shapes is studied. The undesirable
backward motion of the object with respect to the main forward direction is found to decrease for an exponential envelope;
when this envelope is optimized, the backward motion is completely eliminated. 相似文献
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We consider a category of effect algebras and formulate an abstract-hidden variables problem for an object of this category. A notion of indeterministic object is introduced as of an object which induces a Kochen–Specker-type contradiction. A sufficient condition for an object to be indeterministic is derived. An abstract algebraic point of view on a no-hidden variables example constructed by Mermin is given. The notion of a passage to the semiclassical limit is analyzed and refined. 相似文献
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R.S Hansen 《Optics and Lasers in Engineering》1997,28(4):259-275
It is demonstrated that, by using diffuse object illumination, deformation measurements with holographic interferometry can be performed on a specularly reflecting object without the use of any additional coating of the object surface. An analytical expression for the secondary fringe formation is found, and the system is demonstrated only to be sensitive to deformations along the surface normal. A method for carrying out topographic measurements on specularly reflecting surfaces is suggested. The fringe visibility is studied for a rigid rotation of the object by using matrix methods. It is found that maximum fringe visibility is obtained if the recording camera is focused on the surface of the object. 相似文献