由于保偏光纤对轴时须保证旋转的光纤始终在显微镜的焦平面内，故本文设计了保偏光纤同轴度调节系统用于调节光纤相对电动旋转平台旋转中心的位置。采用显微视觉和电动位移平台运动检测出光纤的中心轴与电动旋转平台旋转中心的距离，基于图像信息对二维手动平台实施调节，计算出调节后理论上的同轴度误差。结合显微视觉建立了实验系统。以电动平台旋转轴中心为原点建立直角坐标系，通过图像处理采用最小二乘法得到光纤中心线的直线方程，确定光纤中心与电动平台旋转中心的距离。将基于图像阈值的灰度差分函数作为清晰度函数，用实验方法确定其阈值，从而有效降低白噪声的影响。实验结果显示，经过调节的光纤和电动旋转平台的同轴度误差为3 μm，能够应用在保偏光纤偏振轴的检测中。

When polarization axes of Polarization Maintaining Fibers (PMF) are detected by micro-vision methods in PMF alignment, the rotation axes of fibers must be in the focal plane of the microscope. Therefore, a coaxial adjustment system was designed to adjust the relative position of the fiber to a motorized rotation stage. The distance between the fiber core and the center of rotation stage was detected by the micro-vision and the precise motion of motorized linear stage, and then, based on the image information, the two-dimensional manual linear stages were used to perform the adjustment. After the adjustment, the coaxial error was computed theoretically.Based on the micro-vision,an adjustment system was designed for the experiments.The Cartesian coordinate system was established by taking the center of the motorized rotary stage as the origin. Then, the equation of the straight line of the fiber center and its intercept were obtained by image processing and the least square method, further the distance between fiber center and rotary stage was determined. Moreover, the gray-scale difference function based on image threshold was taken as a sharpness function, and the influence of white noise was effectively eliminated. Experimental results show that the coaxial error between the fiber and the rotary stage is 3 μm after adjustment, which proves that the system can be applied to the detection of the optical fiber polarization axis.