National Repository of Grey Literature 12 records found  previous11 - 12  jump to record: Search took 0.00 seconds. 
Influence of imaging sensors properties on the quality of the quantitative phase image reconstruction
Šulc, Václav ; Antoš, Martin (referee) ; Dostál, Zbyněk (advisor)
This bachelor thesis is focused on imaging sensors noise characteristics and their impact on quantitative phase imaging. From available sensors the darkframes were acquired and analyzed. Computed data of noise standard deviation were used to simulate synthetic holograms for reconstruction of quantitative phase images. A camera Basler acA2040-180km was found to be a most suitable device for holography. The design, fabrication and testing of an effective cooling system for such a device proved to have even better noise characteristics.
Mathematical Methods for Image Processing in Biological Observations
Zikmund, Tomáš ; doc. RNDr.Petr Matula, Ph.D. (referee) ; Krejčí, František (referee) ; Chmelík, Radim (advisor)
The dissertation deals with the image processing in digital holographic microscopy and X-ray computed tomography. The focus of the work lies in the proposal of data processing techniques to meet the needs of the biological experiments. Transmitted light holographic microscopy is particularly used for quantitative phase imaging of transparent microscopic objects such as living cells. The phase images are affected by the phase aberrations that make the analysis particularly difficult. Here, we present a novel algorithm for dynamical processing of living cells phase images in a time-lapse sequence. The algorithm compensates for the deformation of a phase image using weighted least squares surface fitting. Moreover, it identifies and segments the individual cells in the phase image. This property of the algorithm is important for real-time cell quantitative phase imaging and instantaneous control of the course of the experiment. The efficiency of the propounded algorithm is demonstrated on images of rat fibrosarcoma cells using an off-axis holographic microscope. High resolution X-ray computed tomography is increasingly used technique for the study of the small rodent bones micro-structure. In this part of the work, the trabecular and cortical bone morphology is assessed in the distal half of rat femur. We developed new method for mapping the cortical position and dimensions from a central longitudinal axis with one degree angular resolution. This method was used to examine differences between experimental groups. The bone position in tomographic slices is aligned before the mapping using the propound standardization procedure. The activity of remodelling process of the long bone is studied on the system of cortical canals.

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