Národní úložiště šedé literatury Nalezeno 2 záznamů.  Hledání trvalo 0.00 vteřin. 
A method for the visualization of high phase gradients in a microscopic image
Druckmüllerová, Hana ; Martišek, Dalibor (oponent) ; Chmelík, Radim (vedoucí práce)
Holographic microscopy is an unconventional microscopy technique suitable especially for transparent samples. It enables to visualize the refractive index of observed objects. A unique transmitted-light digital holographic microscope (TDHM) has been constructed at Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology. Holograms captured by the microscope are processed by means of a technique based on the Fourier transform in order to reconstruct the intensity and phase of the light waves passing through the observed object. The phase describes the object refractive index and thickness. In places where the object refractive index or thickness changes, also the phase does. The task of this bachelor thesis was to find a method for visualizing places with high phase gradient. A gradient computation method which was created does not require phase unwrapping and is therefore suitable generally for any images. The method was implemented in a computer software called Gradient3D, which enables not only to compute the phase gradient in two and three dimensions, but also to create color images composed from combinations of intensity, phase and gradient. It also contains methods for handling places with low reconstructed intensity where the phase value is unreliable and usually causes false phase gradients. The program has been tested on several image sets from the TDHM capturing biological specimens.
A method for the visualization of high phase gradients in a microscopic image
Druckmüllerová, Hana ; Martišek, Dalibor (oponent) ; Chmelík, Radim (vedoucí práce)
Holographic microscopy is an unconventional microscopy technique suitable especially for transparent samples. It enables to visualize the refractive index of observed objects. A unique transmitted-light digital holographic microscope (TDHM) has been constructed at Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology. Holograms captured by the microscope are processed by means of a technique based on the Fourier transform in order to reconstruct the intensity and phase of the light waves passing through the observed object. The phase describes the object refractive index and thickness. In places where the object refractive index or thickness changes, also the phase does. The task of this bachelor thesis was to find a method for visualizing places with high phase gradient. A gradient computation method which was created does not require phase unwrapping and is therefore suitable generally for any images. The method was implemented in a computer software called Gradient3D, which enables not only to compute the phase gradient in two and three dimensions, but also to create color images composed from combinations of intensity, phase and gradient. It also contains methods for handling places with low reconstructed intensity where the phase value is unreliable and usually causes false phase gradients. The program has been tested on several image sets from the TDHM capturing biological specimens.

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