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提出了一种基于窗口傅里叶脊的离面与面内位移分离方法,应用于数字全息的多分量干涉相位场分离。首先,物光束对称照射待测物体,参考光束直接照射CCD靶面,由CCD相机记录物体变形前后的两幅离轴数字全息图;然后,采用菲涅尔衍射积分法再现物体变形前后的复物光场,再由两幅复物光场共轭相乘构建干涉场,利用幅度区分准则和窗口傅里叶变换处理复干涉场,通过窗口傅里叶脊值的搜索,提取不同灵敏度矢量物光对应的干涉相位分量;再对干涉相位场进行简单数值运算,将面内与离面位移场分离出来。最后,对周边固定、点加载、绕轴向旋转的Al制圆盘三维位移场进行实际测量。实验结果验证了本文方法的有效性。
A method of separating out-of-plane and in-plane displacements based on window Fourier ridge is proposed, which is applied to the separation of multi-component interferometric phase fields in digital holography. First, the object beam illuminates the object to be measured symmetrically, the reference beam directly irradiates the CCD target surface, and the CCD camera records two off-axis digital holograms before and after the object is deformed. Then, Fresnel diffraction integral method is used to reproduce the object before and after deformation Then, the interference field is constructed by the conjugate multiplication of two complex light fields, the interference field is processed by using the amplitude discrimination criterion and the window Fourier transform, and the object vectors of different sensitivity are extracted by searching the Fourier ridge of the window. Corresponding to the phase components of interference; and then the interference phase field simple numerical operation, the plane and out of plane displacement field separation. Finally, the three-dimensional displacement field of Al disk with fixed, point loading and axial rotation is measured. Experimental results verify the effectiveness of the proposed method.