基于相位预测的在线三维测量像素匹配方法

Pixel Matching Method in On-Line Three-Dimensional Measurement Based on Phase Prediction

物体的运动使变形条纹图中物体像素点不对应,因此需要对物体做像素匹配。提出了一种基于相位预测的在线三维测量像素匹配方法。仅投一帧正弦光栅条纹到在线运动的物体上,CCD同步采集相同步距时刻受物体调制的变形条纹图。采用傅里叶变换轮廓术(FTP)方法对采集的变形条纹预测物体不同位置的相位信息,并以该相位信息的特征做像素匹配,实现了物体在各帧条纹图中的像素一一对应,同时匹配后的变形条纹产生等效的等步相移,进而采用等步长相移算法来重构在线运动物体的三维面形。计算机模拟与实验验证了该方法的有效性和可行性。同时,与在线FTP方法进行比较,在线FTP方法和本文方法的均方根误差分别为1.013mm和0.024mm,表明该方法对在线三维测量具有较高的测量精度。

Pixel matching must be done because the coordinates of the object in different captured patterns are not one-to-one corresponding caused by the movement of object.A pixel matching method in on-line three-dimensional measurement based on phase prediction is proposed.Only one fixed sinusoidal fringe is needed to project on a measured object moving on the pipeline.While the object is coming to some positions with a certain adjacent displacement,the deformed patterns modulated by the object are captured synchronously with CCD camera.Dealing the captured deformed patterns with Fourier transform profilometry（FTP）method,the phase information of the object in those positions can be predicted to assist the pixel matching,which realizes the one-to-one corresponding of the object,and extracts the equivalent phase-shifting deformed patterns.So the 3Dsurface shape of the object moving on the pipeline can be reconstructed successfully with an equal phase-shifting algorithm.The results of simulation and experiment verified its feasibility and validity.Meanwhile,compared with the on-line FTP method,the root mean square error derived by the on-line FTP and the proposed method are 1.013 mm and 0.024 mm respectively,which shows the proposed method has higher precision in on-line three-dimensional measurement.