四象限探测器基于高斯分布的激光光斑中心定位算法

Laser spot center location algorithm of four-quadrant detector based on Gaussian distribution

为了提高四象限探测器在FPGA中实时激光光斑位置测量的精度,提出了一种基于高斯分布的光斑中心定位算法。首先,四象限探测器光敏面上分布的激光光斑采用高斯分布模型等效。结合探测器的工作原理,合理设置高斯积分区间,计算出呈高斯分布的光斑在探测器各象限内的光能量,从而对应各象限输出的光电流,得到包含光斑位置信息的正态分布关系式。再通过标准正态分布表查询快速求解出光斑中心位置,将算法在硬件上实时地实现。最后,分别对基于高斯分布的定位算法和基于圆模型的传统算法进行仿真与实验验证。结果表明,基于高斯分布的定位算法的测量精度相较于传统算法提高了43.8%。由此证明基于高斯分布的定位算法能有效提高激光光斑中心位置测量精度。

Laser spot center location algorithm of four-quadrant detector based on Gaussian distribution was proposed to improve the accuracy of real-time laser spot center location measurement in FPGA. Firstly, the laser spot used Gaussian distribution model was equivalently analyzed. Combined with working principle of the four- quadrant detector and a reasonable set of Gauss integration interval, light energy of each quadrant can be calculated. Corresponding to the photocurrent in the same area, Gaussian distribution equations containing location information were deduced. And then, by using the standard Gaussian distribution table, laser spot center location expressions were derived quickly which made the algorithm be implemented in hardware in real time. Finally, simulation and experimental verification were carded out with the algorithm which was based on Gaussian distribution and circular model respectively. The results show that the precision of the algorithm based on Gaussian distribution is increased by 43.8%. Thus, it proves that this algorithm can effectively improve the accuracy of spot center location measurement.