− Autostereoscopic display systems can provide users a natural 3-D visualization environment by projecting stereo video onto the user's eyes. Eye position localization is a central module in this kind of display system when users are allowed to move freely. This paper presents robust 3-D eye tracking techniques that can provide accurate eye positions in real time. Technical batteries comprise: (1) robust face detection based on eigenspace method; (2) real-time face tracking; and (3) eye detection in the obtained face region. According to our implementation on a PC with a Pentium IV