视觉瞄准激光干涉测量编码型水准尺

针对编码型水准尺分划误差的检测，提出了采用视觉瞄准与双频激光干涉测量相结合的方法。构建了编码型水准尺的精密检测系统并对瞄准测量方法进行了研究。当被测条码边缘出现在瞄准视场中，不必微调载尺工作台，即可实现图像和干涉仪测量数据快速采集，并由软件完成瞄准及测量。针对条码边缘图像的检测，首先采用最大方差法分割图像；然后提出图像边缘跟踪法，直接寻找检测边缘，从而避开去除噪声的困难；最后应用概率细分方法对条码边缘定位，提高测量分辨率。经实际测试，该检测系统视觉瞄准标准差为0.23μm，系统稳定性标准差小于0.5μm。该瞄准测量方法提高了测量效率，测量精度高于检测要求4倍，保证了编码型水准尺检测的可靠性。该检测系统已成功应用于编码型水准尺的分划误差检测。

Measuring Code-bar Grade Rod by Vision Collimation and Laser Interferometer

In order to inspecting stripes error of code-bar grade rod, a method of visual collimation and double-frequency laser interferometry is discussed. Precise measurement system of code-bar grade rod is designed and the method of collimation and measurement is investigated. When image of code-bar edge presents on collimation area, the image and the data of laser interferometer are collected rapidly, needing not move worktable carried grade rod tardily. Then collimation and measurement are completed by software program. Image detection of code-bar edge is discussed. First, the algorithm of maximal square deviation is used to image segmentation. Then a way named image edge-tracking is presented to obtain code-bar edge directly, avoiding the difficulty of noise filter. Finally, a fine division method based on probability and statistics theory is applied to locate code-bar edge, improving the resolution of visual collimation. In the practice, the criterion deviation of vision collimation is 0.23μm and the criterion deviation of system stability is below 0.5μm. The method of collimation and measurement improves measurement efficiency and measurement precision is 4 times high than the requirement, it ensures credibility of code-bar grade rod measurement. The measurement system has been used in the stripes error inspection of code-bar grade rod successfully.