Partial aperture imaging by systems with annular phase coded masks

Interferenceless coded aperture correlation holography is a recently developed technique for indirect 3D imaging of objects without two-wave interference. In such systems, the intensity response to a point is first recorded by modulating the light diffracted from a point object by a pseudorandom coded phase mask (CPM). The object intensity response is recorded under identical conditions and with the same CPM by mounting an object at the same axial location as of the point object. The image of the object is reconstructed by a cross-correlation between the above two responses. In the present study, the imaging capabilities of a system with partial apertures are demonstrated by synthesizing the CPM in the shape of a ring. The partial aperture system demonstrates 3D imaging capabilities with an area as low as 1.4% of the total aperture area, which is beyond the limits of a regular imaging system. These superior imaging capabilities of the new technique might be useful for imaging with ground and space telescopes.