  Endoscopy has been an indispensible tool in medical diagnostics, and yet the
demands for reduced unit diameter and enhanced spatial resolution have steadily
been growing for the accurate investigation of distal sites with minimal side
effects. However, the attempts to make use of thin image-guiding media
accompany the degradation in spatial resolution as the micro-optics often
induces aberrations. Here, we present a microendoscope that performs real-time
correction of severe aberrations induced by image-guiding media such as a
bundled fiber. Specifically, we developed a method exploiting the full binary
control of a digital micro-mirror device (DMD) for characterizing the
input-output response of image-guiding media and subsequently compensating the
aberrations. As a proof-of-concept study, we completely eliminated the
pixelation artifact, a severe form of aberration, in endoscopic imaging through
an image fiber bundle and achieved spatial resolution much better than the
diameter of an individual fiber. Our study lays a foundation of applying
extremely thin, but highly aberrant image-guiding media for high-resolution
microendoscopy.
