同源双光路能见度仪是一种基于数字摄像法的能见度仪,光斑提取算法是其能见度反演算法中的关键环节之一。从光斑成像的物理原理出发,提出了两种光 斑提取算法。实验证明,即使没有图像预处理和数据后处理,其结果也和Vaisala LT31的结果具有很好的一致性。在确定上述两种方法中涉及的参数时, 引入加权均方误差参量作为确定参数时的代价函数,该参量相对于其他参量有更好的效果,同时本参量还可以作为评价能见度结果的辅助指标。

Single-light-source dual-light-path transmissometer is a kind of transmissometers based on digital photography. The method of segmenting the light spots from the image is one of the key processes in the derivation of visibility. Based on the formation of the image, two methods of segmenting the light spots are presented. The results computed with the two methods above are matched with the results of Vaisala LT31 very well, even without pre-processing of the images and post-processing of the data. In order to find the parameters involved in the two methods above, weighted mean squared error (WMSE) is introduced as a cost function. As a cost function, WMSE performs better than some other frequently used criterion. At the same time, WMSE can be adopted to assist the judgment of the performances of the methods above.