Wang Zhangying, Li Kui, Gao Nan, Meng Zhaozong, Zhang Zonghua
Opt Express. 2024 Nov 4;32(23):41603-41618. doi: 10.1364/OE.542643.
Fringe projection profilometry (FPP) has been widely utilized in many fields due to its non-contact, high accuracy, high resolution and full-field measurement capabilities. However, the limited dynamic range of the camera sensor can result in overexposure of high-reflective parts in industrial production measurement. To effectively solve the above issue, this paper proposes a 3D shape measurement method for the high-reflective surface based on a color camera. Firstly, the optimal exposure time for the low-reflective region is estimated using the relationship between the standard variance of the phase error and the modulation. Twelve blue phase-shifted fringe patterns and a uniform blue image are utilized to obtain 3D shape of high-reflective surface. Secondly, captured images are separated into red, green and blue components. The fused Gaussian low-pass filtering method with different cut-off frequencies is used to filter and denoise the green or red components and the true intensity of the blue component in the saturated regions is calculated by the unsaturated intensity of the green or red components based on the calibrated crosstalk matrix. Then the image in saturated regions is fused and normalized with the unsaturated region. The absolute phase obtained from the fused normalized fringe patterns is converted into 3D data. Finally, experiments have been carried out on measuring. The experimental results show that the proposed method is capable of obtaining the 3D shape of the surface of a high-reflective object with fewer patterns and high measurement accuracy.
条纹投影轮廓术（FPP）因其具有非接触、高精度、高分辨率和全场测量能力，已在许多领域得到广泛应用。然而，相机传感器有限的动态范围可能导致工业生产测量中高反射部分出现过曝现象。为有效解决上述问题，本文提出一种基于彩色相机的高反射表面三维形状测量方法。首先，利用相位误差标准差与调制度之间的关系估计低反射区域的最佳曝光时间。利用十二幅蓝色相移条纹图案和一幅均匀蓝色图像获取高反射表面的三维形状。其次，将采集到的图像分离为红、绿、蓝分量。采用具有不同截止频率的融合高斯低通滤波方法对绿色或红色分量进行滤波去噪，并基于校准的串扰矩阵，通过绿色或红色分量的不饱和强度计算饱和区域蓝色分量的真实强度。然后，将饱和区域的图像与不饱和区域进行融合并归一化。从融合归一化条纹图案中获得的绝对相位被转换为三维数据。最后，进行了测量实验。实验结果表明，该方法能够以较少的图案获得高反射物体表面的三维形状，且测量精度高。
