Fast terahertz corneal imaging system with automatic motion compensation: application to in vivo mapping of hydration gradients

Terahertz time-domain spectroscopy (THz-TDS) has shown strong potential for noncontact corneal hydration sensing and surface-profile metrology, but in vivo imaging remains challenging because the curved corneal surface requires precise phase matching and rapid acquisition to suppress motion artifacts. We report a fast single-pixel THz corneal imaging system that combines electronically controlled optical sampling (ECOPS) for kilohertz waveform acquisition with a direct - drive two-axis beam-steering mirror and a pair of custom hyperbolic-elliptical lenses optimized for wide-field spherical scanning. The system acquires a 40°×40° field of view in 0.8 s (and 60°×60° in