相位去包裹问题广泛存在于条纹投影形貌测量中。提出了一种相移编码去包裹方法,该方法在求解相位时使用多步相移法,并在额外的一幅编码图像中,将标记条纹级数的编码嵌入到相移量中。解码时,通过分析各像素点处不同相移的光强信息序列,可以求解该点处的编码相移量,从而获得绝对相位。该方法只需要少量图像,且可以逐点去包裹,适用于不连续物体的形貌测量,但是容易受到投影仪和相机的噪声影响。通过增加互补的编码条纹图像,提出了一种改进的相移编码去包裹方法,在实现不连续物体形貌测量的同时,显著增强了噪声鲁棒性。经过仿真分析和实验,验证了所提的相移编码去包裹方法的有效性。

The problem of phase unwrapping is widespread in fringe projection profilometry. In this paper, a phase-shift coding unwrapping method is proposed. This method uses the multi-step phase-shift method to solve a phase and embeds the code of the mark fringe series into the phase-shift amount in an additional coded image. When decoding, one can solve the coded phase-shift amount at the point and thus obtain the absolute phase by analyzing the light intensity information sequence of different phase shifts at each pixel point. This method requires only a few images and can unwrap point by point. It is suitable for the shape measurement of a discontinuous object but it is easily affected by the noise of the projector and the camera. By adding the complementary coded fringe images, we propose an improved phase-shift coding unwrapping method, which can not only be used for the shape measurement of discontinuous objects but also significantly enhance the noise robustness. The simulation analysis and experiment confirm the effectiveness of the proposed phase-shift coding unwrapping method.