双摄像机视线追踪系统中摄像机不能直接测量视野范围以外物体的空间坐标，为解决这一问题提出了一种基于平面镜的系统标定方法。首先对双摄像机进行标定，确定两摄像机之间的关系，建立统一的世界坐标系。其次，根据平面镜成像原理确定显示器屏幕及光源镜像的空间坐标，进而确定光源及屏幕的空间位置。经实验证明该方法精度较高，在受试者距离屏幕500~600 mm时，视线落点平均精度可达到1°左右，满足大多数视线追踪应用场合的需要。

In stereo cameras gaze tracking system, cameras can not directly measure the object spatial coordinates outside field of view outside. In order to solve this problem, a system calibration method based on plane mirror is proposed. First, to calibrate stereo cameras to determine the relation between two cameras, a unified world coordinate system is created. Secondly, according to the plane mirror imaging principle, the spatial coordinates of the monitor screen and light source image are decided. The spatial location of light source and screen is determined. The experimental results show that the method has high precision. When the user is away from the screen 500~600 mm, the average accuracy of gazing point can reach 1°, and meet the needs of most gaze tracking applications.