为缩短衰减倍率调整的时间，提高激光参数测试的效率，提出激光光强快速衰减算法。衰减倍率精确调整量由当前衰减倍率和采集到的光斑光强真实的最大灰度值共同决定。当因光电接收器件(CCD)饱和造成采集光斑图像失真时，即衰减倍率过小时，由于激光光斑的光强通常满足高斯分布，通过对光斑图像进行处理，去除饱和部分光强信息，对剩余部分光强信息利用最小二乘法进行三维高斯拟合，还原出激光光斑光强的真实分布并获得最大灰度值; 当衰减倍率过大时，根据采集光斑图像可以直接获得当前最大灰度值，最后通过计算获得最佳的衰减倍率调整值，实现了激光光强快速准确的调整。算法的有效性通过步进电机带动的双轮可变衰减器及CCD配合得到验证。

The fast attenuation algorithm of laser intensity is presented in this paper to shorten the time of precisely adjusting attenuation rate. The accurate adjustment of attenuation rate is determined by both the current attenuation rate and the maximal gray level of practically sampled spot image. When the collected spot image was distorted by the saturation of the optoelectronic receiving device, the light spot image could be dealt with by removing the saturated portion of the light intensity information and simulating by tree-dimension Gaussian fitting based on the least squares method. Then the real distribution and amplitude of the laser intensity could be restored. If the attenuation rate is very large, the present amplitude can be obtained directly. The appropriate attenuation adjustment rate can be calculated based on the real distribution and amplitude of the laser intensity. Laser intensity was adjusted fast and accurately. The validity of the fast attenuation algorithm was testified by the experiment of CCD and stepper motor-driven double wheels attenuator.