水线精确提取是基于机器视觉的水尺计重系统中的技术难题。针对自然场景下采集的图像存在着光照不均匀、场景复杂等问题, 通过帧间作差结合图像配准对图像进行预处理; 提出一种基于三角隶属函数关系的迭代分割方法; 通过线性采样和双线性插值法, 提取出完整的水线。实验证明了该水线提取算法的稳定性和准确性。

Precise extraction of waterline　is a technical problem in draft survey system based on computer vision. In view of natural scene, images might be affected by non-uniform illumination and various scenes etc. The preprocessing of the image is performed though frame difference combined with image registration; An iterative segmentation method is proposed based on triangle membership function; Linear sampling and bilinear interpolation method are utilized to extract waterline completely. A lot of experiments show the robustness and accuracy of the waterline extraction algorithm.