ABSTRACT Shearography is only sensitive to deformation in the shearing direction, and the deformation of object defects after loading may occur in multiple directions. This work reports a multi-direction shearography system that uses spatial phase-shift methods to detect the object from multi-shearing directions, effectively avoiding the missed detection of directional defects. A single laser is utilized to illuminate an object, and a single CCD camera records images in the multiplexed Mach–Zehnder interference system. First, the aperture stops in suitable size and location are set to produce different spatial carrier frequencies. Second, the shearing amount is independently adjusted by using different devices. Finally, the Fourier transform method is used to extract the phase information from the frequency domain. This system can be used for nondestructive testing of multi-directional defects and the feasibility of the method is verified by theoretical analysis and experiment.

中文翻译：

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基于多路Mach-Zehnder干涉系统的多方向剪切成像

摘要 剪切成像仅对剪切方向的变形敏感，加载后物体缺陷的变形可能发生在多个方向。这项工作报告了一种多方向剪切成像系统，该系统使用空间相移方法从多剪切方向检测对象，有效避免了方向缺陷的漏检。单个激光用于照亮物体，单个 CCD 相机在多路复用 Mach-Zehnder 干涉系统中记录图像。首先，设置合适尺寸和位置的孔径光阑以产生不同的空间载波频率。其次，剪切量是通过使用不同的设备独立调整的。最后，采用傅里叶变换方法从频域中提取相位信息。