Range selective phase-shifting frequency-modulated digital holography with temporal-heterodyning

Abstract

We demonstrate that a time of flight (TOF) camera can be used to perform range selective temporal-heterodyne frequency-modulated continuous wave digital holography (TH FMCW DH). The modulated arrayed detection of a TOF camera allows efficient integration of holograms at a selected range with range resolutions significantly less than the optical system’s depth of field. TH FMCW DH also allows for on-axis geometries to be achieved, where background light not at the internal modulation frequency of the camera is filtered out. Range selective TH FMCW DH imaging was achieved for both image holograms and Fresnel holograms using on-axis DH geometries. A 2.39 GHz FMCW chirp bandwidth resulted in a DH range resolution of 6.3 cm.

Range-selective FMCW digital holography for imaging through scattering environments

“…This work was done on the optical bench and the object being imaged was placed less than 1 meter in front of the sensor array. Hammond et al used a time-of-flight camera in combination with the FMCW DH technique to perform range-selective imaging with on-axis phase shifting DH [14]. Again, this work was done with object distances less than 1 meter in front of the camera.…”