基于圆特征的视觉测量方法简单且精度高，因此具有广泛的机器视觉应用，但单个圆特征的单目视觉位姿估计存在二义性问题。为了有效剔除虚假解，基于三线构型的姿态估计方法，提出了一类基于角度约束的圆位姿二义性消除方法。对具有先验信息的三线构型，利用三线构型与相机系的姿态关系可以得到圆平面法向量的一个角度约束。若三线构型不具有先验信息，利用二视图三线构型的相对姿态估计可以得到一个二视图间圆法向量的角度约束，这两类角度约束都可以排除圆的虚假法向量。实验结果表明，该方法可有效消除圆位姿二义性，第一种角度约束可以达到99.2%的成功率，第二种角度约束可以达到96.7%的成功率。

Due to the efficiency and accuracy, the visual measurement method based on circular features is widely used in computer vision applications. However, the duality problem interferes the process of monocular vision pose estimation with a single circle feature. In order to exclude of the false solution effectively, a method utilizing angular constraint to solve the ambiguity is proposed based on the attitude estimation with the three lines configuration. For a known three lines configuration, an angular constraint about the normal vector of the single circle is deduced with the attitude between the configuration and the camera coordinate. If the three lines configuration is unknown, an angular constraint between the normal vectors of the circle in two camera views is deduced with the relative attitude estimation with a pair of matched three lines configuration. Both of the angular constraints can be applied to exclude the false normal vector of the circle. Experimental results indicate that the proposed approach can effectively solve the duality problem. The success rate is up to 99.2% for the first angular constraint, and the success rate is up to 96.7% for the second angular constraint.