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Supplementary_video.mp4 (16.94 MB)

Demonstration of real-time resolution improvement in fiber bundle inline holographic microscopy using multiple illumination sources

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posted on 2024-02-09, 18:26 authored by Michael Hughes, Callum McCall
The video demonstrates that resolution enhancement in fiber bundle inline holographic microscopy can be achieved during live imaging. The video shows a Python-based graphical user-interface which displays processed and refocusing holograms as they are streamed from the camera. A High Resolution USAF imaging target was imaged, initially at a distance of 140 microns from the bundle tip. The video initially shows the refocused hologram without resolution enhancement, at a frame rate of 30 fps. The exposure was set at 16 ms and kept constant throughout. Resolution enhancement is then turned on, and the resolution visibly improves. With resolution enhancement turned on, raw frames are captured at 25 fps, giving a net enhanced-resolution frame rate of 3.1 fps. In principle a rate of 7.5 fps could be achieved using the camera and the python processing code, but the overheads of the python GUI and the screen recording software resulted in lagging at faster than 3.1 fps. When the sample is translated, motion artefacts are now seen, as expected from a multi-frame approach. Finally, use of a calibration LUT to allow fast refocusing in the GUI is demonstrated. The calibration LUT was built from depths from 100 to 500 microns in steps of 20 microns. The USAF target is shown being moved away from the bundle using a translation stage, and the numerical refocusing then adjusted in the GUI to bring it back into focus, changing which calibration is used from the LUT in the process.


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