Development of head-free remote eye gaze detection system

对开发非接触式、基于远程视频的高精度眼睛凝视检测系统进行了研究，在该系统中，用户可以将头部移动约10厘米，以便使用视光将信息输入计算机。在最终的眼睛凝视检测系统的原理中，通过两个立体宽摄像头来检测精确的三维瞳孔位置，可以捕捉到用户面部的完整图像。另一台安装在云台上的狭窄摄像头对准用户的眼睛，捕捉到放大的眼睛图像。在图像中，检测到了瞳孔图像的中心和光源的角膜反射中心。利用它们的相对位置，确定了视线光相对于窄缝相机光轴的角度。视光与目标物的交叉点被检测为眼睛凝视点，直到2003财年，红外LED在每个立体摄像机的光圈周围呈环形排列。T…的两个环多个发光二极管与视频的奇偶信号同步开启，并在每个摄像头中交替获得瞳孔和暗瞳孔图像。通过区分这些图像，可以更容易地检测到瞳孔。计算了瞳孔的3D位置，并使窄缝相机指向瞳孔。在狭窄的摄像机上，将波长不同于立体宽幅摄像机的LED环连接到光圈附近和距离较远的地方，以相同的方式检测瞳孔，并在明亮的眼睛图像中检测到肉眼反射。2004财年，提出了一种眼睛凝视定标方法，该方法利用眼球光学元件围绕眼球视轴的轴对称形状。这可以很容易地校准眼睛凝视点，只需查看PC屏幕上的一个已知点和狭窄的摄像头。实验结果表明，检测到的人眼视点在屏幕的某些位置存在系统误差。然而，屏幕到被摄体面部距离的变化并不影响眼睛凝视检测的结果。这一结果表明了这种眼睛凝视检测方法的可纤维性。此外，当耳部反射位于瞳孔边缘时，用窄缝摄像机获取的图像很难估计出瞳孔中心。这一问题的改善使眼睛凝视点在屏幕上的离散度小于1.5厘米。较少

Studies for development of non-contact, remote video-based, high-precision eye-gaze detection systems in which users can move their head around 10 cm were conducted for information input into a computer using light of sight. In the principle of the final eye gaze detection system, the precise 3-D pupil position was detected by two stereo wide cameras which can grab whole image of users' face. Another narrow camera fixed on a pan-tilt unit was directed toward user's eye, and grabbed a magnified eye image. In the image, the center of the pupil image and the center of the corneal reflection of the light source were detected. Using their relative positions, the angle of the light of sight relative to the light axis of the narrow camera was determined. The intersection between the light of sight and the visual object was detected as the eye gaze point.Until 2003 fiscal year, the infrared LEDs were arranged in a ring shape around the aperture of each of the stereo cameras. The two rings of t … More he LEDs were switched on synchronously with an odd/even signal of the video and, the pupil and dark pupil images were alternately obtained in each camera. Diffentiating these images eased pupil detection. The 3D positions of the pupil was calculated and the narrow camera was made to direct toward the pupil. On the narrow camera, the rings of LEDs having a different wavelength from that of the stereo wide cameras were attached to near the aperture and a little far from there, and the pupil was detected in the same fashion, and the carnal reflection was detected in the bright eye image.In 2004 fiscal year, an eye gaze calibration method was proposed, which utilized an assumption that the optics of eye ball has a shape of axial symmetry around the visual axis of the eyeball. This could easily calibrate eye gaze point by just looking at one known point on a PC screen and the narrow camera. The experimental results indicated that the detected eye gaze points showed the systematic errors in some positions of the screen. However, the change of the distance between the screen and the face of the subject did not influence the eye gaze detection results. This result showed the efibctiveness of this eye gaze detection method. In addition, it was difficult to estimate the pupil center in the image obtained from the narrow camera when the oarneal reflection was located at the edge of the pupil. The improvement of this problem made the dispersion of the eye gaze point on the screen less than 1.5 cm. Less