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    • 摘要: 传统相位偏折测量术测量透明物体前表面三维形貌时,物体前后表面发生反射的条纹叠加在一起,出现寄生反射现象,导致无法准确恢复前表面的三维形貌。因此提出透明物体寄生反射抑制的前表面相位偏折测量方法。使用连续小波变换获取物体前表面初始相位,并结合多频相移方法构建优化模型实现相位提取,对其梯度积分实现透明物体三维重建。利用上述理论对透明玻璃与平凸透镜表面的重建效果展开评估,与多频相移方法进行比较,实测3 mm玻璃平板重建误差从21.81 μm减小为15.72 μm,4 mm玻璃平板精度误差从19.98 μm减小至13.46 μm,平凸透镜曲率半径误差从39.44 μm减小为16.59 μm,实现高精度形貌测量。

       

      Abstract: When measuring the front surfaces of transparent objects by using phase measuring deflectometry (PMD), the reflections from the front and back surfaces of the object are superimposed, resulting in parasitic reflection, which makes it difficult to accurately reconstruct the front surface of objects. In this paper, we proposed a front-surface PMD method that suppresses parasitic reflections of transparent objects. Firstly, the initial phase of the front surface was extracted by continuous wavelet transform. Then, an optimized model was constructed by combining the multi-frequency phase-shifting method to obtain the accurate phase. Finally, the gradient integral was used to restore the three-dimensional (3D) morphology of the transparent object surface. The surfaces of transparent glasses and plano-convex lenses were measured using the above theory. Compared with the multi-frequency phase-shifting method, the reconstruction error of the 3 mm glass plate decreased from 21.81 μm to 15.72 μm, the error of the 4 mm glass plate is reduced from 19.98 μm to 13.46 μm, and the radius of curvature error of the plano-convex lens is reduced from 39.44 μm to 16.59 μm, thereby improving the accuracy of the front surface of transparent objects measurements.