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The analysis of limits for multimode fibre imaging
Štolzová, Hana ; Kozubek, Michal (oponent) ; Dostál, Zbyněk (vedoucí práce)
Multimode fibers are the imaging tool of a significant potential in in-vivo microendoscopy. Recently, this method has seen a great development, thanks to the improvements in computational and other technologies, such as digital spatial light modulation. The aim of this work was to find specific limits of multimode fiber imaging and to present their computer simulation. The effect of illumination of the optical system containing the multimode fiber on its focussing and imaging capability was investigated. By analysing the data obtained from simulations and experiments, it has been found that the various levels of the Gaussian beam truncation by a projected multimode fiber numerical aperture results in a significant variance in the imaging capabilities of the system. Therefore, it seems that the multimode optical fibers are not a completely random medium. Observing the quality of the focusing, it was found that low truncated beams (beam-waist around 50% of the projected fiber numerical aperture), have the highest performance. This fact was verified by experimental measurements. Imaging using similarly truncated beams showed the best contrast transmission capability. However, when analysing the resolution of two pointlike objects, the beams with a significantly larger waist and a higher degree of truncation, of 100% or more, were most appropriate. The presence of this difference forces the person using the imaging system containing the multimode fiber to consider several aspects, in what environment the particular optical system will be used and which imaging quality indicator will be considered the most important.
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The analysis of limits for multimode fibre imaging
Štolzová, Hana ; Kozubek, Michal (oponent) ; Dostál, Zbyněk (vedoucí práce)
Multimode fibers are the imaging tool of a significant potential in in-vivo microendoscopy. Recently, this method has seen a great development, thanks to the improvements in computational and other technologies, such as digital spatial light modulation. The aim of this work was to find specific limits of multimode fiber imaging and to present their computer simulation. The effect of illumination of the optical system containing the multimode fiber on its focussing and imaging capability was investigated. By analysing the data obtained from simulations and experiments, it has been found that the various levels of the Gaussian beam truncation by a projected multimode fiber numerical aperture results in a significant variance in the imaging capabilities of the system. Therefore, it seems that the multimode optical fibers are not a completely random medium. Observing the quality of the focusing, it was found that low truncated beams (beam-waist around 50% of the projected fiber numerical aperture), have the highest performance. This fact was verified by experimental measurements. Imaging using similarly truncated beams showed the best contrast transmission capability. However, when analysing the resolution of two pointlike objects, the beams with a significantly larger waist and a higher degree of truncation, of 100% or more, were most appropriate. The presence of this difference forces the person using the imaging system containing the multimode fiber to consider several aspects, in what environment the particular optical system will be used and which imaging quality indicator will be considered the most important.
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