A computer-generated moiré profilometry based on flat image demodulation is proposed. A sinusoidal fringe pattern and its background light are modulated by two-frequency carrier fringes, respectively, to combine a composite grating. While this composite grating is projected onto the measured object, the composite deformed pattern can be captured by CCD camera. So the sinusoidal deformed pattern and its corresponding flat image can be demodulated from the composite deformed pattern. And the AC component of sinusoidal deformed pattern is calculated by the subtraction between the demodulated sinusoidal deformed pattern and the flat image. Compared with normal computer-generated moiré profilometry, a more intact AC component can be obtained directly no matter how severe the frequency aliasing condition is. Meanwhile, the three-dimensional (3D) shape of object can be reconstructed only using this composite deformed pattern which shows the application in real-time measurement. Experimental results show the feasibility and validity of the proposed method.

提出了一种基于平面图像解调的计算机生成莫尔轮廓测量法。正弦条纹图案及其背景光分别通过双频载波条纹调制，组合成复合光栅。当这种复合光栅被投影到被测物体上时，复合变形图案可以被 CCD 相机捕捉到。因此可以从复合变形图案中解调出正弦变形图案及其对应的平面图像。并且正弦变形图案的AC分量通过解调的正弦变形图案与平面图像之间的减法计算。与普通的计算机生成的莫尔轮廓相比，无论频率混叠条件多么严重，都可以直接获得更完整的交流分量。同时，只有使用这种复合变形图案才能重建物体的三维（3D）形状，这显示了在实时测量中的应用。实验结果表明了该方法的可行性和有效性。