Head-Free, Remote Eye-Gaze Detection System Based on Pupil-Corneal Reflection Method With Easy Calibration Using Two Stereo-Calibrated Video Cameras
Head-Free, Remote Eye-Gaze Detection System Based on Pupil-Corneal Reflection Method With Easy Calibration Using Two Stereo-Calibrated Video Cameras
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DOI：
10.1109/tbme.2013.2266478
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发表时间：
2013-06
影响因子：
4.6
通讯作者：
Y. Ebisawa;K. Fukumoto
中科院分区：
文献类型：
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作者：
Y. Ebisawa;K. Fukumoto
我们开发了一个基于瞳孔-角膜反射方法的视线检测系统，该系统允许较大的头部运动，并实现了简单的视线校准。该系统包含两个光学系统，由相机和连接到相机的近红外光源等组件组成。光源有两个不同波长的同心LED环。内环和外环分别生成亮瞳孔图像和暗瞳孔图像。从通过减去亮瞳孔图像和暗瞳孔图像而创建的差异图像中检测瞳孔。光源还产生角膜反射。瞳孔的3-D坐标由使用两个光学系统的立体匹配方法确定。相机图像中从角膜反射中心到瞳孔中心的矢量被确定为r。视线与通过瞳孔中心和相机（光源）的线之间的角度表示为θ。关系式θ = k|\bm r|假设，其中k是常数。该理论意味着允许用户的头部移动并且促进注视校准过程。在自动校准方法中，当用户在PC屏幕上环顾四周而不注视任何特定校准目标时，k被自动确定。在单点校准方法中，要求用户注视PC屏幕上的一个校准目标，以校正光轴和视轴之间的差异。在两点标定法中，为了校正θ与|R|，要求用户注视两个目标。实验结果表明，本文提出的三种标定方法逐步提高了视线检测的精度。此外，对于用户的七个头部位置，视角的平均注视误差小于1°。
We have developed a pupil-corneal reflection method-based gaze detection system, which allows large head movements and achieves easy gaze calibration. This system contains two optical systems consisting of components such as a camera and a near-infrared light source attached to the camera. The light source has two concentric LED rings with different wavelengths. The inner and outer rings generate bright and dark pupil images, respectively. The pupils are detected from a difference image created by subtracting the bright and dark pupil images. The light source also generates the corneal reflection. The 3-D coordinates of the pupils are determined by the stereo matching method using two optical systems. The vector from the corneal reflection center to the pupil center in the camera image is determined as r. The angle between the line of sight and the line passing through the pupil center and the camera (light source) is denoted as θ. The relationship θ = k | \bm r | is assumed, where k is a constant. The theory implies that head movement of the user is allowed and facilitates the gaze calibration procedure. In the automatic calibration method, k is automatically determined while the user looks around on the PC screen without fixating on any specific calibration target. In the one-point calibration method, the user is asked to fixate on one calibration target at the PC screen in order to correct the difference between the optical and visual axes. In the two-point calibration method, in order to correct the nonlinear relationship between θ and | r |, the user is asked to fixate on two targets. The experimental results show that the three proposed calibration methods improve the precision of gaze detection step by step. In addition, the average gaze error in the visual angle is less than 1° for the seven head positions of the user.