Research Projects

Abstract: 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.

Paper Links:

This work is published in the Transactions of Computational Imaging (IEEE Xplore link). You may find a preliminary copy on Arxiv.org, and a local version of the PDF here [13 MB].

Citation (APA):

Holloway, J., Asif, M. S., Sharma, M. K., Matsuda, N., Horstmeyer, R., Cossairt, O., & Veeraraghavan, A. (2016). Toward Long-Distance Subdiffraction Imaging Using Coherent Camera Arrays. IEEE Transactions on Computational Imaging, 2(3), 251-265.

[+] BibTex Citation

@article{holloway2016toward,
author = {Jason Holloway and M. Salman Asif and Manoj Kumar Sharma and Nathan Matsuda and Roarke Horstmeyer and Oliver Cossairt and Ashok Veeraraghavan},
journal={IEEE Transactions on Computational Imaging},
title={Toward Long Distance, Sub-diffraction Imaging Using Coherent Camera Arrays},
year={2016},
volume={2},
number={3},
pages={251-265},
ISSN={2333-9403},
month={Sept}
}

Code:

Download the Matlab source code on Github.

Data:

Download simulation data on Github. Download experimental data for the Dasani, fingerprint, and USAF datasets as a zip file [257 MB].

Poster

Download the poster (48" x 36") for this project: Hi-Res PDF [28.6 MB] or the Lo-Res PDF [5.3 MB]