中文摘要：

从目标边界对称性出发，首先提出了基于广义对称特性的外边界提取技术．然后，距离势能模型（Snake模型）被用以修复所得初始外边界轮廓中的断裂、凹凸不平等问题，以得到连续、光滑、闭合的目标外边界曲线．此外，针对预处理处理过程中的目标边缘局部断裂现象，提出了一种16—8连接方法．最后，本文以交通障碍物目标为研究对象，通过对行人、车辆等多类障碍物的研究和分析，证明该方法是一种提取多类障碍物目标外边界的有效算法．

英文摘要：

Inspired by target boundary symmetries, a novel external boundary extraction method is presented based on generalized symmetry properties firstly. The distance potential model （Snake model） is then used to repair fracture and unevenness problems in the initial extracted boundary to generate a continuous, smooth and closed target boundary contour curve. Moreover, a 16-8 connection method is proposed to connect local fracture edges during the target pretreatment process. Finally, obstacles such as pedestrians, vehicles, etc. in the traffic scene are selected for experimental study. The experimental results show that the approach is effective for extracting the external boundaries of multiple obstacles.