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提出一种新的相移方法,该方法将原独立的水平和垂直一维正弦光栅集成为单幅正交正弦光栅图,再采用双频光栅相移方法,从而实现仅通过某一特定方向相移即可获取两正交相位分布,并进而计算出待测面的梯度分布并由梯度分布恢复待测表面面形。详细介绍了双频光栅相移方法,推导了相移方向与双频光栅相移的对应关系。在传统方法中,须独立投影或显示水平和垂直一维正弦光栅,且分别进行相移测量,因此共需2×N幅图像(N≥3);而在双频正交光栅相移方法中,最少需要5幅图像。当采用机械相移时,传统方法需要二维相移机构,而该方法仅需一维相移机构,因此该方法具有成本低、测量速度快、结构简单等优点。实测的眼镜片结果,验证了该方法的可行性。
A new phase shift method is proposed, in which the original independent horizontal and vertical one-dimensional sinusoidal grating is integrated into a single orthogonal sinusoidal grating pattern, and then a dual-frequency grating phase shift method is used to realize the phase shift through only a specific phase The two orthogonal phase distributions can be obtained, and then the gradient distribution of the surface to be measured can be calculated and the surface profile to be measured can be recovered from the gradient distribution. The phase shift method of dual-frequency grating is introduced in detail, and the corresponding relationship between the phase shift direction and the phase shift of dual-frequency grating is deduced. In the conventional method, a horizontal and vertical one-dimensional sinusoidal grating needs to be projected or displayed independently, and the phase shift measurement is separately performed, so a total of 2 × N images (N ≧ 3) are required. In the dual-frequency orthogonal grating phase shift method , A minimum of 5 images are required. When using mechanical phase shift, the traditional method requires two-dimensional phase shift mechanism, which only needs one-dimensional phase shift mechanism. Therefore, this method has the advantages of low cost, fast measurement speed and simple structure. The measured results of the ophthalmic lens verify the feasibility of the method.