Spatial-chromatic encoding cosmetic contact lenses for enhanced natural eye tracking

Vision-based analysis of ocular features represents the predominant approach for eye tracking. However, these features are highly susceptible to interference from illumination, eyelid/eyelash occlusion, and individual variations, leading to low recognition rates and diminished tracking accuracy. To address these limitations, eye movement feature enhanced cosmetic contact lenses are proposed, implementing a spatial-chromatic encoding strategy. Employing a head-mounted eye tracker integrated with RGB cameras, this system enables accurate and robust gaze tracking in natural environments. Under challenging illumination, the lenses achieve a 93% feature recognition rate, significantly surpassing pupil recognition and tolerating highly off-axis camera placement. Eye movement model and human eye tracking demonstrate superior accuracy (<1°), gaze direction estimation, and continuous fixation positioning. Utilizing these lenses, diverse eye-tracking applications are demonstrated, including image identification, reading analysis, and outdoor interaction. This approach advances the development of lightweight, unobtrusive eye-tracking systems and facilitates broader application of gaze-based interaction technology in real-world settings.