基于条纹级次编码与调制的结构光相位展开算法

Phase Unwrapping Algorithm for Structured Light Based on Fringe-Order Encoding and Modulation

利用相位级次的编码和调制方法将相位级次信息叠加到相移图像中,提出了一种直接利用相移图像进行相位解包裹的方法。在投影端,提出了一种邻接不重复德布鲁因序列,并用该序列对相位级次进行编码,然后将该周期级次编码序列调制、叠加到多步相移图像中。相应地,在解码阶段,从拍摄到的相移图像中同时解调、分解出包裹相位和周期级次编码序列,通过序列的匹配还原真实周期级次信息,并最终准确地解包裹出绝对相位。以四步相移法为例,本文方法相比传统的时间相位解包裹算法,投影图片从10张(64个相位周期)缩减到了4张,提高了测量效率。

This paper first uses the phase-order encoding and modulation methods to superimpose the phase-order information into the phase-shifting image,and then proposes a method to directly use the phase-shifting image to unwrap the phase.On the projection side,this paper firstly proposes an adjacent non-repetitive De Bruijn sequence,uses this sequence to encode the phase order,and then modulates and superimposes the periodic order code sequence into the multi-step phase shift image.Correspondingly,in the decoding stage,this paper demodulates and decomposes the wrapped phase and period order coding sequence from the captured phase-shifting image at the same time,then restores the true period order information through sequence matching,and finally unwraps the absolute phase accurately.We take the four-step phase shifting method as an example.Compared with the traditional temporal phase unwrapping algorithm,the method in this paper reduces the number of projection images from 10(64 phase periods)to 4,which improves the measurement efficiency.