Optical incoherent imaging using annular synthetic aperture with the superposition of phase-shifted optical transfer functions

Abstract

The optical incoherent synthetic aperture (SA) has wide applications in astronomy and biomedical optics. Super-resolution imaging can be achieved through SAs with an effective size several times larger than the size of the physical apertures. In this Letter, we propose a new, to the best of our knowledge, method to realize optical incoherent SA imaging. Instead of scanning the entire area of the full SA, we show that similar imaging performance can be achieved by scanning only along its perimeter. At any given time, only a single pair of sub-apertures located at the SA perimeter is open and reflects the incident light toward an image sensor. For each location of the two sub-apertures, two interfering images are captured. The phase difference between the two sub-apertures is zero for one interfering image and π for the other. The image of the object is reconstructed by superposition of all the interfering images from some of the sub-aperture locations and with the two-phase differences, 0 and π, between the two sub-apertures. Optical experiments have been performed using reflective objects, and the results demonstrate similar imaging capabilities as that of direct imaging with the aperture size of the SA. Furthermore, we have compared the proposed SA imaging results with the results of annular and full aperture direct imaging.

Advanced Imaging Methods Using Coded Aperture Digital Holography

“…COACH can image targets with an incoherent synthetic aperture, with the advantage that the relatively small apertures move only along the perimeter of the relatively large synthetic aperture [62]. Although interferenceless imaging systems are simpler and more power efficient than systems with wave interference, the latter systems still have an important role in the technology, and the annular synthetic aperture [62,63] is an example of using two-wave interference between beams reflected from a pair of sub-apertures located along the aperture perimeter. More details about these advances and others of COACH and I-COACH can be found in two review articles [64][65][66].…”