小尺寸光斑中心的高精度定位算法

光斑中心定位是光学测量中的关键技术之一，针对小尺寸光斑中心定位算法精度低等问题，提出了一种具有高精度的小尺寸光斑中心两步定位算法。通过寻找一阶导数零交叉点的方法确定光斑中心所在的像素级坐标，然后利用该中心邻域内不饱和点的灰度信息进行高斯拟合计算光斑中心亚像素级坐标。实验结果表明:在无噪声污染光斑图像中，与其他经典算法相比，两步定位算法误差远小于0.05像素，保证了光斑中心的高精度定位，且光斑成像越接近理想高斯分布，精度越高。

High-precision center location algorithm of small-scale focal spot

Spot center location is a key technique in the field of optical measurement. A Two-step method for center location of small-scale focal spot with high precision was proposed to solve the problem as the low precision when using classic center location algorithms. First, the pixel-level center could be located through zero crossing of the first derivative in the focal spot image. And then, the unsaturated part of the focal spot beside the pixel-level center was used to fit the Gaussian surface to calculate the sub-pixel center. Experimental results show that, when comparing with other classic center location algorithms, the error of the two-step method is much less than 0.05 pixels in the spot image without background noise. The two-step method can keep high-precision center location of the focal spot. If the imaging model of the focal spot is much more similar with the ideal Gaussian spread function, the precision is higher.