Conics typically include ellipses, hyperbolas, and parabolas with equal eccentricities that intersect infinite line at absolute points. According to the imaging characteristics of conics under a pinhole camera, a dual image of the absolute points can be obtained. By analysing the representative coefficient matrix of the dual image, the algebraic relationship between the image of the centre of the conic and its projection matrix can be obtained; thus, the vanishing line can be determined by the pole-polar relationship of the dual image of the absolute points. A group of orthogonal vanishing points can be obtained to determine the camera intrinsic parameters by two conics with aligned principal axes. The feasibility and robustness of the algorithm are verified by simulation data and real experiments.

圆锥曲线通常包括椭圆、双曲线和具有相等偏心率的抛物线，它们在绝对点处与无限线相交。根据针孔相机下圆锥的成像特性，可以获得绝对点的对偶图像。通过分析对偶图像的代表系数矩阵，可以得到圆锥中心图像与其投影矩阵的代数关系；因此，消失线可以由绝对点的对偶图像的极极关系确定。可以得到一组正交的消失点，通过两个主轴对齐的圆锥曲线来确定相机的内参。通过仿真数据和实际实验验证了算法的可行性和鲁棒性。