Camera phasing in multi-aperture coherent imaging

Abstract

The resolution of a diffraction-limited imaging system is inversely proportional to the aperture size. Instead of using a single large aperture, multiple small apertures are used to synthesize a large aperture. Such a multi-aperture system is modular, typically more reliable and less costly. On the other hand, a multi-aperture system requires phasing sub-apertures to within a fraction of a wavelength. So far in the literature, only the piston, tip, and tilt type of inter-aperture errors have been addressed. In this paper, we present an approach to correct for rotational and translational errors as well.

Piston Error Extraction from Dual-Wavelength Interference Patterns Using Phase Retrieval Technique

“…The optical synthetic aperture telescope (includes the optical segmented telescope and multi-aperture telescope) is considered to be a mainstream structure for achieving large aperture and high-resolution imagery of new scientific observations [1]. An important work in achieving optimal performance is that the sub-apertures or segments must be phased within a fraction of the wavelength, i.e., correcting for the piston error between apertures and segments [2][3][4].…”

Multi-transmitter aperture synthesis with Zernike based aberration correction

“…Each sub-aperture captures the pupil field using some holographic imaging technique, then the measured sub-aperture fields are placed in a common pupil plane corresponding to the physical locations of the sub-apertures, and the composite pupil plane field is Fourier transformed, thus forming a digital image. Using a sharpness measure (applied on the image formed), the inter-aperture aberrations (including piston, tip, tilt, rotation, and shift) and intra-aperture aberrations (such as defocus, astigmatism, coma) can be corrected [3].…”