Disclose the example of the imaging system for head-mounted display (HMD). Imaging system may include image camera forward, and the surface of the display of HMD may include the off-axis diffraction optical element (DOE) or heat mirror for being configured as reflecting light to imaging camera. DOE or heat mirror can be segmented. The imaging system can be used for eyes tracking, bio-identification, the reconstruction of the multiregion of eyes 3D shape etc..