涡流法、超声法测量深孔截面轮廓尺寸精度低，而光学单点扫描法测量效率低。介绍了一种基于圆结构光的复杂深孔内轮廓3维测量系统，提出了一种采用FFT分析和差分分析进行测试数据处理的方法，能够实现快速高精度测量。测试系统主要由圆结构光发生器、扩束锥镜、成像锥镜、镜头和CCD组成，对于获取的每一幅被测截面的结构光图像，首先提取光条中心，对光条中心上的点作最小二乘法拟合获取光条中心拟合圆心，并以此圆心点将光条中心线展开，展开波形中存在整体形状误差，主要由圆心偏心误差、椭圆形状误差两个周期性误差分量构成，由于二者振动频率与细节分量的振动频率不相同，借助于FFT分析，将两个误差分量分离出来，进而采取措施减小其对系统的影响；差分分析用于去除阴线和阳线之间的过渡线。该方法提高了阴线圆与阳线圆尺寸计算的精度和效率，实验结果表明，系统内径测量精度达到005mm。

For the measurement of complicated deep hole profile, both eddy current method and ultrasonic method characterize low accuracy, at the same time, optical scanning with single light point has low efficiency. A 3D measurement system based on ring-structured-light is presented which characterizes high accuracy and processing speed. A data processing method using FFT analysis and difference analysis has been proposed. The system consists of a ring-structured-light generator, a reflection cone mirror, an imaging cone mirror, an optical lens, and a CCD camera. Firstly, we capture a structured-light image of the measured inner surface and extract the stripe center locus of it. Then we find the center of the stripe center locus by curve fitting using the least squares method. Subsequently, we stretch the stripe center image from its center point. In the waveform of the stretch-out-view, there exist eccentricity error and ellipse shape error. The frequencies of these two periodical error components are different from the frequency constitution of the detail component. We can separate them from the waveform with the help of FFT analysis. Therefore the eccentricity error and the ellipse error can be minimized and the accuracy of the system is improved greatly. Difference analysis was used to remove the transition line between the exterior circle and the inner circle. The method can improve both the accuracy and the efficiency of the inner surface parameters measuring. Experiments show that the diameter measuring accuracy can get 0.05mm.