Shekel, Noam, and Ori Katz
. “Using fiber-bending-generated speckles for improved working distance and background rejection in lensless micro-endoscopy
”. Opt. Lett.
45.15 (2020): , 45
, 15, 4288–4291. Web. Publisher's VersionAbstract
Lensless flexible fiber-bundle-based endoscopes allow imaging at depths beyond the reach of conventional microscopes with a minimal footprint. These multicore fibers provide a simple solution for wide-field fluorescent imaging when the target is adjacent to the fiber facet. However, they suffer from a very limited working distance and out-of-focus background. Here, we carefully study the dynamic speckle illumination patterns generated by bending a commercial fiber bundle and show that they can be exploited to allow extended working distance and background rejection, using a super-resolution fluctuations imaging analysis of multiple frames, without the addition of any optical elements.
Weinberg, Gil, and Ori Katz
. “100,000 frames-per-second compressive imaging with a conventional rolling-shutter camera by random point-spread-function engineering
”. Opt. Express
28.21 (2020): , 28
, 21, 30616–30625. Web. Publisher's VersionAbstract
We demonstrate an approach that allows taking videos at very high frame-rates of over 100,000 frames per second by exploiting the fast sampling rate of the standard rolling-shutter readout mechanism, common to most conventional sensors, and a compressive-sampling acquisition scheme. Our approach is directly applied to a conventional imaging system by the simple addition of a diffuser to the pupil plane that randomly encodes the entire field-of-view to each camera row, while maintaining diffraction-limited resolution. A short video is reconstructed from a single camera frame via a compressed-sensing reconstruction algorithm, exploiting the inherent sparsity of the imaged scene.