Pupil and Glint Detection Using Wearable Camera Sensor and Near-Infrared LED Array

Sensors

Jianzhong Wang²  Guangyue Zhang²  Jiadong Shi¹ 

[1] School of Mechatronical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China

关键词: wearable camera sensor;    pupil detection;    glint detection;    circular ring rays location;    total least squares fitting;    Gaussian fitting;   

DOI  :  10.3390/s151229792

来源: mdpi

【 摘 要 】

This paper proposes a novel pupil and glint detection method for gaze tracking system using a wearable camera sensor and near-infrared LED array. A novel circular ring rays location (CRRL) method is proposed for pupil boundary points detection. Firstly, improved Otsu optimal threshold binarization, opening-and-closing operation and projection of 3D gray-level histogram are utilized to estimate rough pupil center and radius. Secondly, a circular ring area including pupil edge inside is determined according to rough pupil center and radius. Thirdly, a series of rays are shot from inner to outer ring to collect pupil boundary points. Interference points are eliminated by calculating gradient amplitude. At last, an improved total least squares is proposed to fit collected pupil boundary points. In addition, the improved total least squares developed is utilized for the solution of Gaussian function deformation to calculate glint center. The experimental results show that the proposed method is more robust and accurate than conventional detection methods. When interference factors such as glints and natural light reflection are located on pupil contour, pupil boundary points and center can be detected accurately. The proposed method contributes to enhance stability, accuracy and real-time quality of gaze tracking system.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.