反向条纹投影技术是一种应用于在线或批量、快速而稳定的光学三维面形检测技术，近年来得到广泛关注和应用。提出了一种反向条纹生成的新方法，利用了正向映射变换方法传递坐标以及摄像机坐标系中同名点所在的水平和垂直方向两条等相位线，求解它们的交点就可以得到投影器对应像素点在摄像机坐标系中的位置，再生成待投影的反向条纹。在分析了两条等相位线特点的基础上，提出了求解等相位线交点的优化算法剪枝优化算法。该算法逐步缩小两条等相位线上有效像素点的规模，直至找到交点周围邻近的4个整像素点，再拟合出两直线方程，联立方程精确解出亚像素精度的交点坐标。并将本剪枝优化算法与文献[10]的主要方法进行了对比分析，计算机模拟实验得到了相位标准差，分别为0.000798 rad和0.0046 rad；实物实验得到的相位标准差分别为0.0431 rad和0.0292 rad。对比结果表明：该优化算法有效提高了反向条纹生成的精度，并且能以较快的速度精确搜索到交点周围4个像素点，减小了反向条纹生成的时间。

Inverse projected fringe technique is a fast and robust optical three-dimensional (3D) shape inspection technique, which is applied to online or batch inspection. In recent years, people pay more attention to the technique and apply it in many fields. A new method for generating inverse fringe is proposed. This method adopts normal mapping transform relationship to transfer coordinate. Then, it adopts the horizontal and vertical equal phase lines to obtain crosspoint which is the homologous pixel of the pixel on projector plane, so we can get the inverse fringe finally. The pruning optimization algorithm for getting the crosspoint is proposed, based on equal phase lines′ characteristic. The algorithm gradually decreases the unnecessary pixels of two equal phase lines. Finally, it can find four nearest pixels of the crosspoint, then the crosspoint can be calculated by solving two linear equations. The algorithm comes to sub-pixel level. The pruning optimization algorithm and the method proposed in Ref.[10] are used in contrast experiments. Standard phase differences in the computer simulation experiment are 0.000798 rad and 0.0046 rad respectively. Standard phase differences in the real experiment are 0.0431 rad and 0.0292 rad, respectively. The conclusion indicates that the optimization algorithm can improve precision of inverse fringe projection effectively, and reduce time consumption by exactly searching four nearest pixels with fast speed.