任意相移最小二乘法迭代的在线三维检测

On-line three-dimensional inspection using randomly phase-shifting fringe based on least-square iteration

为了简化采用满周期等相移算法的在线相位测量轮廓术(PMP)在实际测量过程中系统装调环节的繁杂程度,同时避免栅线方向和运动方向不严格平行引入附加相移降低解相精度,提出了基于最小二乘法迭代的在线三维检测方法。在测量过程中,任意栅线方向的正弦光栅被投影于物体表面,采用像素匹配技术获得不同时刻拍摄到的变形条纹图的等效相移条纹图,其相移量由投影系统和物体位移共同决定且为任意值。最后,采用最小二乘法迭代计算相位。实验结果表明:在不断改变投影到参考面上光栅栅线方向的情况下,该系统的测量结果稳定,均方根误差均不高于0.169 9mm。由于该方法放宽了测量系统空间位置的约束条件,提高了测量的灵活程度,使在线PMP更具普适性。

An on-line Phase Measuring Profilometry（PMP）based on least-square iteration was proposed to simplify the complexities of system installment and to avoid the influence of additional phase ？shifting caused by the non-parallelism between grating lines and object＇s displacement in the PMP based on synchronous detection.In measurement processing,the sinusoidal grating with arbitrary grid line direction was projected onto an object,and a CCD was used to capture the deformed fringe patterns.After pixel matching,fringe patterns were used to evaluate the phase distribution.The phase-shifting was determined as arbitrary values by both projection system and object＇s displacement.Finally,the least-square iteration was used to calculate the phases.The experiment result shows when the grating line directions on the reference plane are changed,the measurement resultsare stable,and the root-mean-square error is less than 0.169 9mm.It concludes that the proposed method relaxes the restriction of the spatial location of measurement equipment,increases the measurement flexibility and makes the PMP more applicable.