Range selective digital holographic imaging using FMCW lidar.

The integration of chirped frequency modulated continuous wave (FMCW) lidar techniques into digital holography enables range selective holographic imaging well beyond the depth of field of the system. The technique uses FMCW transmit and reference beams. By frequency shifting the reference beam to compensate for the typical FMCW beat frequency associated with a particular range, temporally stable holograms are formed for objects at the selected range. The holograms associated with objects at all other ranges oscillate and integrate towards zero. Experimental demonstrations of the technique are presented, showing enhanced imaging of objects at different ranges and cancellation of obscuring objects. The technique is expandable to range-Doppler selective digital holographic imaging.