Hovanesian J D, Hung Y Y
Appl Opt. 1971 Dec 1;10(12):2734-8. doi: 10.1364/AO.10.002734.
A grid is projected onto an object and focused into a viewing camera which is offset from the angle of illumination. When the image is superimposed by double exposure or by filtering with the image of another object, contour-difference moiré fringes appear. By the use of two offset projectors, measurements of contour sums or contour doubling may be accomplished. The properties, limitations, sensitivity, and procedures are analyzed and discussed. The method lends itself to image enhancement and is extended to the study of vibration analysis in real time. In the latter application, time-average moiré fringes appear according to the zeroth-order Bessel function, which contains the modal amplitude function in its argument.
将一个网格投射到一个物体上，并聚焦到一个与照明角度偏移的观察相机中。当图像通过双重曝光或用另一个物体的图像进行滤波叠加时，轮廓差莫尔条纹就会出现。通过使用两个偏移投影仪，可以完成轮廓和或轮廓加倍的测量。分析并讨论了该方法的特性、局限性、灵敏度和步骤。该方法适用于图像增强，并扩展到实时振动分析的研究。在后者的应用中，根据零阶贝塞尔函数会出现时间平均莫尔条纹，其自变量中包含模态振幅函数。
