一种基于眼球结构的视线映射几何模型设计

Design of Gazing Geometrical Model Based on Eyeball Structure

为解决视线追踪系统中视线方向计算精度受用户头动的影响,在立体视觉的基础上设计了一种基于眼球结构的视线映射几何模型。在眼球模型结构基础上,利用普尔钦斑与光源位置计算得到了角膜曲率中心,通过它与瞳孔中心的连线求得眼球光轴,并利用光轴和视轴之间的夹角计算得到了真实的视线方向—视轴。研制了一种双摄像机环形红外光源,通过交替照射用户脸部,可在任意一个摄像机得到"亮瞳"和"暗瞳"的相邻两帧图像。将这两帧图像做差得到瞳孔位置,采用椭圆拟合方式求得瞳孔中心,加之在"暗瞳"图像上得到的普尔钦斑中心,为模型的计算提供了参数,实验结果证明该模型能解决头动对视线计算精度的影响。

Based on eyeball structure,gazing geometrical model using stereovision is designed to improve computing gaze precision in the presence of head motion.The curvature center of cornea is obtained by Purkinje Image and light source,and the optical axis is the line linking pupil center and the curvature center of cornea.The visual axis,which is the true gaze direction of the user,can be determined subsequently after knowing the angle deviation between the visual axis and optic axis.The two novel light sources for stereovision are developed.The way of getting pupil position is to do subtraction of two images,the ＂bright pupil＂ and the ＂dark pupil＂,which are gained by illuminating user＇s eyes alternately.The pupil center is located by ellipse fitting when the Purkinje image is gained in the ＂dark pupil＂,and these parameters are satisfied for modeling.The result of experiment proves that the model can resolve the influence of gazing precision caused by head-motion.