  Mobile-phones have facilitated the creation of field-portable, cost-effective
imaging and sensing technologies that approach laboratory-grade instrument
performance. However, the optical imaging interfaces of mobile-phones are not
designed for microscopy and produce spatial and spectral distortions in imaging
microscopic specimens. Here, we report on the use of deep learning to correct
such distortions introduced by mobile-phone-based microscopes, facilitating the
production of high-resolution, denoised and colour-corrected images, matching
the performance of benchtop microscopes with high-end objective lenses, also
extending their limited depth-of-field. After training a convolutional neural
network, we successfully imaged various samples, including blood smears,
histopathology tissue sections, and parasites, where the recorded images were
highly compressed to ease storage and transmission for telemedicine
applications. This method is applicable to other low-cost, aberrated imaging
systems, and could offer alternatives for costly and bulky microscopes, while
also providing a framework for standardization of optical images for clinical
and biomedical applications.
