基于三坐标测量机的双频虚拟光栅投影轮廓测量方法

Dual-frequency Virtual Grating Projection Profile Measurement Method Based on Three-coordinate Measuring Machine

针对被测物体产生的突变部分三维成像不连续问题,提出基于三坐标测量机的双频虚拟光栅投影轮廓测量方法。在三坐标测量机中设置一个试验台,用于控制CCD相机、投影仪等设备的运动方向,相位解算变形光栅图像,得到全测量范围中的相位主值分布与附加相位。CCD相机通过记录虚拟光栅,获取由不同频率调制的变形光栅像与基于等效周期的相位主值分布,完成双频调制相位综合。通过构建物体表面变形条纹相位分布,联立其与被测物体高度分布函数关系,依据解得的双频率综合后高度值偏差,推导出周期整数倍取值条件,实现轮廓三维测量。实验结果表明,该方法保留了突变区域或边沿部分的频谱信息,测得的三维数据准确度较高。

Aiming at the discontinuity of the three-dimensional imaging of the sudden change part of the measured object,a dual-frequency virtual grating projection profile measurement method based on a three-coordinate measuring machine is proposed.A test bench is set up in the coordinate measuring machine to control the movement direction of CCD cameras,projectors and other equipment,phase-calculate the deformed grating image,and obtain the main phase value distribution and additional phase in the full measurement range.The CCD camera obtains the deformed grating image modulated by different frequencies and the phase principal value distribution based on the equivalent period by recording the virtual grating,and completes the dual-frequency modulation phase synthesis.Constructing the phase distribution of the deformed fringe on the surface of the object,combine it with the height distribution function of the measured object,derive the value conditions of integer multiples of the period according to the height value deviation after the dual frequency synthesis obtained,and realize the contour three-dimensional measurement.The experimental results show that the proposed method retains the spectral information of the sudden change area or the edge part,and the measured three-dimensional data has high accuracy.