基于增量光栅尺的纵横转换图像细分算法实现

Realization of image subdivision algorithm with transformation from horizontal to vertical scale based on incremental grating ruler

针对现有光栅测量方法不能兼顾高速与高精度的问题,为适应电子制造装备高速运动和高精密定位的位移反馈要求,提出基于增量式光栅尺的纵横转换细分测量原理和相应的图像快速处理算法。为了提高光栅图像采集处理速度,搭建基于FPGA的硬件测试平台,先将采集到的图像进行滤波和二值化处理,然后对图像先进行纵横坐标相加,求取像素点最小值得到交点位移值。实验结果表明:应用纵横转换算法并搭载FPGA测试系统,能够达到0.029μm的分辨率,精度达到0.3μm。

Aiming at solving problem of existing grating ruler measurement method with which high speed and high precision can not be taken into account, measurement principle of transformation from horizontal to vertical scale of incremental grating and corresponding image pro- cessing algorithms are proposed in order to meet the requirement of feedback displacement for high speed motion and high precision positioning of electronic manufacturing equipment. In or- der to improve speed of grating image acquisition and processing, a hardware testing platform based on FPGA is built. Firstly, images collected by FPGA system are filtered and binarized, then processed images are added with vertical coordinates and horizontal coordinates accordingly. In this way point displacement value is obtained by calculating smallest pixels. Experimental results show resolution of 0.029 μm and precision of 0.3 μm can be achieved by using FP- GA testing system with vertical and horizontal conversion algorithms.