提出了一种基于单帧采集的相移测量轮廓术(Phase Shift Profilometry, PSP), 该方法保留了传统相移测量轮廓术的相移特性和高精度的特点, 同时又能在实时测量的时候仅采集单帧变形条纹。在传统的N步相移测量轮廓术中, 需要投影N(N>2)帧相移正弦光栅, 并采集N帧变形相移条纹, 而且随着N值增大测量精度更高。所提方法只需要投影一帧正弦光栅, 并采集一帧变形条纹, 同时对相移步数的提高可以让测量精度随之变高, 而且在静态测量和实时三维测量中都可以保证单帧采集的特征。此外, 该方法的数学模型与传统PSP的相比更加简洁, 得到的包裹相位仅与物体本身的高度有关, 无需对参考平面和被测物体分别进行相位运算和解调。相比于其他单帧测量方法精度更高, 有效地避免了对变形条纹频谱直接滤波带来的频谱缺失, 或者是其他基于PSP的实时测量的颜色混叠、动态范围受限的问题。仿真和实验结果表明了该方法的可行性和有效性。

Within the framework of the linearized theory of electroelastic wave propagation, a model of a piezoelectric structure with a prestressed functionally graded coating made of piezoceramics of a trigonal system with a symmetry class of 3m is considered. The ferroelectric LiNbO₃ is used as the main material of the structure. The initial deformed state of the coating material is homogeneous, induced by the action of initial mechanical stresses and an external electrostatic field, the properties of the coating continuously change in thickness. By the example of the problem of the propagation of SH-waves from a remote source for structures with an inhomogeneous prestressed coating in the case of an electrically free and short-circuited surface, the influence of the nature and localization of the inhomogeneity of the coating on the features of SAW propagation is studied. The separate and combined effects of initial actions on changes in the physical properties of the structure, the transformation of the surface wave field, and the change in the SAW velocities in a wide frequency range is studied. The results obtained in this work are useful for understanding the dynamic processes in prestressed piezoelectric structures, in the optimization and design of new structures and devices on SAW with high performance characteristics.Within the framework of the linearized theory of electroelastic wave propagation, a model of a piezoelectric structure with a prestressed functionally graded coating made of piezoceramics of a trigonal system with a symmetry class of 3m is considered. The ferroelectric LiNbO₃ is used as the main material of the structure. The initial deformed state of the coating material is homogeneous, induced by the action of initial mechanical stresses and an external electrostatic field, the properties of the coating continuously change in thickness. By the example of the problem of the propagation of SH-waves from a remote source for structures with an inhomogeneous prestressed coating in the case of an electrically free and short-circuited surface, the influence of the nature and localization of the inhomogeneity of the coating on the features of SAW propagation is studied. The separate and combined effects of initial actions on changes in the physical properties of the structure, the transformation of the surface wave field, and the change in the SAW velocities in a wide frequency range is studied. The results obtained in this work are useful for understanding the dynamic processes in prestressed piezoelectric structures, in the optimization and design of new structures and devices on SAW with high performance characteristics.

在线相位测量轮廓术(PMP)中，当被测物体运动速度较高时，所采集的变形条纹往往为运动模糊图像，使得复原误差增大，严重时可能导致三维重建无法进行。将在线PMP运用于钢轨外形及表面缺陷的在线三维测量时，为了实现钢轨表面模糊变形条纹的清晰化，本文对维纳滤波法、点扩散函数算法、盲解卷积算法和Richardson-Lucy算法等几种模糊图像复原算法进行了对比分析，用峰值信噪比对模糊条纹图像的复原效果进行评估。同时，研究了车辆运行速度和图像复原效果之间的关系，得出了复原效果与运行速度之间的关系曲线，进行了误差分析，并用在线PMP实现了钢轨外形的三维重建。理论及实验结果表明：在对钢轨外形轮廓及表面缺陷的在线三维测量时，Richardson-Lucy算法的复原效果最佳，图像复原程度与车辆运行速度呈多项式关系。

针对镜面物体三维测量系统中两显示屏无法精确平行正对的问题, 提出了一种在镜面物体三维测量系统中通过软件产生变形条纹等效两显示屏精确平行正对的方法。该方法首先采用机器视觉技术标定两显示屏的外参。然后基于所标定的外参, 利用软件编程产生等效两显示屏平行正对的变形条纹, 变形条纹通过半透半反镜后所成的像在相机坐标系内呈现前后精确平行正对的关系。最后, 利用对应两个显示屏上的变形条纹计算相应位置相位的差值, 并通过均方根误差定量评定所提出的方法。实验结果表明, 所提出的方法能将水平方向的均方根误差缩减为原来的24.21%, 竖直方向的均方根误差缩减为原来的8.15%, 从而提高三维测量系统的精度。

根据刚体各部位具有变换一致性这一特性, 提出一种采用高维数据聚类的目标跟踪方法。从数学理论方面证明提出的度量方法可以应用于目标跟踪, 称其为高维数据聚类跟踪器(HDDC tracker)。 该算法框架如下, 首先, 采用Harris检测器对模板与跟踪区域进行特征提取; 然后利用这些特征的空间信息对所提取的特征进行编组; 接着计算模板特征组与跟踪区域特征组间的仿射变换阵; 最后, 采用高维数据聚类对这些仿射变换阵进行度量, 将那些相似仿射阵对应的跟踪区域作为跟踪目标。实验表明: HDDC tracker能够有效地跟踪具有仿射形变的目标, 并且性能优于先进跟踪算法。

将格莱姆 -施密特正交化法引入投影栅形貌测量, 提出了一种新的两步相移轮廓术。首先将 2幅随机相移正弦条纹通过 DLP投影仪投射到待测物体上, 由 CCD相机采集受物体形貌调制的变形光栅条纹图, 再选择合适大小窗口经像素逐点均值法消除变形栅线图中的背景成分, 然后对消背景栅线图进行格莱姆 -施密特正交化, 得到 2幅消背景相移栅线图对应的正交基, 由正交基解调出相位数据。最后对面膜样品进行了实际测量, 并与其它方法进行了比较分析, 实验结果证明了该方法的有效性。

We describe a fiber optic hydrophone array system that could be used for underwater acoustic surveillance applications (e.g. military, counter terrorist, and customs authorities in protecting ports and harbors), offshore production facilities or coastal approaches as well as various marine applications. In this paper, we propose a new approach to underwater sonar systems using the voltage-controlled liquid crystals and simple multiplexing method. The proposed method permits measurement of sound under water at multiple points along an optical fiber using the low cost components and standard single mode fiber, without complex interferometric measurement techniques, electronics or demodulation software.

提出了一种非接触式结构光测量液面微变形剖面曲线的方法。基于几何透射虚栅变形的原理，推导了液面离面变形与水底虚栅面内位移之间的数学关系。将一张单向几何光栅（频率为1~5 line/mm）置于盛有已发生变形的水的透明水槽下方，并在水槽上方布置电荷耦合器件(CCD)相机，记录下因液面离面变形而产生的透射虚栅变形图。使用条纹中心算法对所采集的变形栅图进行细化、赋级和插值运算，可得到该虚栅图的位移矢量场。将之代入所推导的数学关系式中，即可迭代求得液面的离面变形剖面曲线。运用该方法对一分硬币漂浮于水面时引起的液面离面变形剖面曲线进行求解绘制，所测得结果与已有文献的结果相比较相差仅为2%，证明了该方法的有效性和可行性。