一种快速的绝对相位求解算法及其在高温锻件自动化测量中的应用  

A fast absolute phase solving algorithm and its application in automatic measurement of high temperature forgings

作　　者：郭延艳 钟凯[2,3] 何万涛 张洪军 江浩 Guo Yanyan;Zhong Kai;He Wantao;Zhang Hongjun;Jiang Hao(School of Mechanical and Electrical Engineering,Lingnan Normal University,Zhanjiang 524048,China;State Key Laboratory of Material Processing and Die&Mould Technology,Huazhong University of Science and Technology,Wuhan 430074,China;Research Institute of Huazhong University of Science and Technology in Shenzhen,Shenzhen 518000,China;Wuhan Vision 3D Technology Ltd.,Wuhan 430074,China)

机构地区：[1]岭南师范学院机电工程学院,广东湛江524048 [2]华中科技大学材料成形与模具技术国家重点实验室,湖北武汉430074 [3]深圳华中科技大学研究院,广东深圳518000 [4]武汉惟景三维科技有限公司,湖北武汉430074

出　　处：《锻压技术》2022年第11期207-213,共7页Forging & Stamping Technology

基　　金：深圳市基础研究面上项目(JCYJ20210324142007022);湖北省重点研发计划项目(2021BAA049);国家自然科学基金资助项目(51675165,51505134)。

摘　　要：为提高基于结构光的高温锻件在线自动化测量的光栅投影与相位计算速度、减小零件热辐射对测量精度的影响、降低环境振动造成的精度损失,提出了一种只需要4幅不同频率光栅投影的、不需要相移的快速相位求解算法。在分析传统多频4步相移的相位求解对高温锻件测量效率与精度影响的基础上,首先,从余弦光栅图像中分离出交流分量,对其利用离散信号的希尔伯特变换代替多步相移来计算相位;然后,根据多频外差法的频率混合得到合成频率的合成相位图;最后,根据相应的反三角函数的值域区间,对合成相位进行平移计算展开相位。仿真结果表明,该方法可以显著提高计算效率,有效减少测量过程停留,降低热辐射和振动对测量精度的影响。现场测量结果表明,该方法可以满足锻件全尺寸数据的测量需求,为锻造过程实时监控、及时消除异常波动、提高和控制锻件精度提供了保障。In order to improve the grating projection and phase calculation speed of on-line automatic measurement for high temperature forgings based on structured light and reduce the influence of part thermal radiation on measurement accuracy as well as reduce the accuracy loss caused by environmental vibration, a fast phase solving algorithm that required only four grating projections with different frequencies without phase shift was proposed. Based on the analysis of the influence of the traditional phase solving with multi-frequency and four-step phase shift on the measurement efficiency and accuracy of high temperature forgings, firstly, the AC component was separated from the cosine grating image, and the Hilbert transform of discrete signal was used to calculate the phase instead of multi-step phase shift. Then, according to the frequency mixing of the multi-frequency heterodyne method, the synthetic phase diagram of the synthetic frequency was obtained. Finally, according to the value range of corresponding inverse trigonometric function, the synthetic phase was shifted to calculate the unwrapped phase. The simulation results show that this method can significantly improve the calculation efficiency, effectively reduce the stoppage of the measurement process, and reduce the influence of thermal radiation and vibration on the measurement accuracy. The field measurement results show that this method can meet the measurement requirements of the full-size data for forgings and provide a guarantee for the real-time monitoring of the forging process, the elimination of abnormal fluctuations in time, and the improvement and control of the accuracy for forgings.

关 键 词：多频光栅 相位计算 高温锻件 希尔伯特变换 自动化三维测量 

分 类 号：TH741[机械工程—光学工程]