  In this work, we propose using camera arrays coupled with coherent
illumination as an effective method of improving spatial resolution in long
distance images by a factor of ten and beyond. Recent advances in ptychography
have demonstrated that one can image beyond the diffraction limit of the
objective lens in a microscope. We demonstrate a similar imaging system to
image beyond the diffraction limit in long range imaging. We emulate a camera
array with a single camera attached to an X-Y translation stage. We show that
an appropriate phase retrieval based reconstruction algorithm can be used to
effectively recover the lost high resolution details from the multiple low
resolution acquired images. We analyze the effects of noise, required degree of
image overlap, and the effect of increasing synthetic aperture size on the
reconstructed image quality. We show that coherent camera arrays have the
potential to greatly improve imaging performance. Our simulations show
resolution gains of 10x and more are achievable. Furthermore, experimental
results from our proof-of-concept systems show resolution gains of 4x-7x for
real scenes. Finally, we introduce and analyze in simulation a new strategy to
capture macroscopic Fourier Ptychography images in a single snapshot, albeit
using a camera array.
