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Introduction to the signal processing in broadcasting chain
Beneš, Filip ; ZIKMUND, Tomáš (advisor) ; URBAN, Ondřej (referee)
The thesis deals with the processing of audio signal for radio and television broadcasting with emphasis on dynamics processing of music audio signal in radio broadcast chain. It deals with the question of modifying in the musical content and also the art work of the sound engineer.
The basic dynamics processing, the principle of how the transmission chain works and as a special part the analysis of parts of the broadcasting processor are described here. The thesis offers an insight into individual parts of the processor including a warning about the possibility of their negative influence on the content.
The thesis includes the world’s most widespread and in Czech Republic available audio broadcasting platforms.
It is accompanied by an illustrative experiment with that compares a music recording before and after both analog and digital broadcasting chain passage pointing out its basic influences.
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Tomographic measurement of industrial parts at temperature below freezing point
Šárközi, Rudolf ; Oberta,, Peter (referee) ; Zikmund, Tomáš (advisor)
X-ray computed tomography presents and ultimate for non-destructive investigation of objects. Under normal circumstances is the object placed on stage and the temperature of the object is defined by ambient air. However there are also cases when observation at freezing or high temperatures is needed to reveal thermal stability of observed object. Naturally the size of used tomography equipment and the object just like form of cooling or heating are subjected to final design. This work provides a summary of used methods for temperature controlled tomography. Furthermore handles about design of cooling chamber capable to reach -40°C by preserving relative high X-ray transparency. As an addition that showed up as a response to additional requirements is here presented a heating chamber, in which the object can be maintained at 80°C . All test and scans were carried out on GE phoenix v|tome|x L240 industrial computed tomography scanner.
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Role of Smarca5 (Snf2h) during transcription of transfected DNA template.
Zikmund, Tomáš ; Stopka, Tomáš (advisor) ; Smetana, Karel (referee)
Cellular and tissue characteristics are results of dynamic regulation of gene expression. DNA wrapped into proteins, referred to as chromatin, requires involvement of mechanisms guiding accessibility of specific sequences. In higher organisms, chromatin remodeling proteins are indispensable in regulating chromatin structure including ISWI ATPase SMARCA5. SMARCA5 is involved in almost any transaction on DNA including transcription, however precise in vivo role of SMARCA5 in these processes remains unknown. To advance understanding of specific role of SMARCA5 in the development of chromatin structure during transcription we devised cellular model in which SMARAC5 level is manipulated while chromatin structure development and transcriptional response are monitored. Our data indicate that the transfected DNA template that is transcribed is enriched with histone H3 and its specific methylation of Histone H3 lysine (K) 4, a mark of active chromatin structure. Overexpression of SMARCA5 results within the reporter gene coding sequence in ~2,5-3 fold increase of both H3 occupancy an its modification H3K4Me3. Increased DNA template commitment into chromatinization is associated with repression of reporter gene expression. These results are supported by studies indicating dynamic development of nucleosomal...
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Data processing for tomographic reconstruction
Dospiva, Jindřich ; Žídek, Jan (referee) ; Zikmund, Tomáš (advisor)
This thesis deal with data processing from x-ray tomographic system. The primary focus is put on the description of projection refining taking place before tomographic reconstruction. The particular method for data processing from system Nano3DX is also suggested. It uses open software ASTRA tomography toolbox, which enable executing of tomographic reconstruction on the graphics card in MATLAB environment. There is also used correction for sample movement, denoising algorithm in projections and calculation the centre of rotation. Results of proposed procedure are demonstrated on tomographic data from measured samples and compared with processing software from the manufacturer.
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X-ray computed tomography of cartilage tissue of embryos
Tesařová, Markéta ; Křivánek,, Jan (referee) ; Zikmund, Tomáš (advisor)
Research of the cartilage is standardly realized by optical microscopy on histological slices. However, for better understanding of shape-organizing processes, imaging in 3D is required. This thesis deals with X-ray computed tomography of mouse embryos. Specifically, it focuses on visualization of craniofacial cartilage. The thesis summarizes the basic principles of X-ray computed tomography. Short research study dealing with staining of soft tissues for X-ray is also provided. The procedure of implementation of the tomographic measurement of mouse embryos stained by PTA is described. This procedure includes the staining protocol, fixing the sample and setting of the CT machine. Subsequent segmentation and creating of a 3D model of cartilage is also desribed. Results for every step of this procedure are demonstrated at the mouse embryos of developmental stage from 12.5 to 17.5 days. In order to improve data quality and standardization of the whole process, parameters of X-ray tube and temperature conditions during the tomographic measurement are explored. Finally, resulting models of craniofacial cartilage are shown with the possibility of subsequent analysis.
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Evaluation of dental pulp treatment based on the X-ray micro computed tomography
Břínek, Adam ; Jiřík, Radovan (referee) ; Zikmund, Tomáš (advisor)
This work deals with processing and analysis of micro-CT images of dental-canals filled by~two materials (AH-plus and NaMPC). For that reason, six dog-teeth were scanned in the X-Ray Micro CT Research Lab. The main aim was to produce an algorithm (in Matlab) that evaluates the quality of filling of dental canals (quality of filling materials). The algorithm performs the segmentation of dental canals and calculates their borders. Also, the algorithm measures the percentage contacts of filling materials with dental walls. Moreover, the algorithm provides masks of dental canals according to requirements of the commercial program VG Studio, that evaluates the porosity of filling materials. The results of percentage contacts and porosities show on not-remarkable differences of tested filling materials.
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Utilisation of phase contrast in X-ray computed tomography
Kalasová, Dominika ; Švéda,, Libor (referee) ; Zikmund, Tomáš (advisor)
X-ray computed tomography is a nondestructive method for 3D imaging of inner structure of objects; it is, however, restricted by absorption properties of materials. With phase contrast imaging, observation of samples with low absorption or with parts with similar absorption becomes possible. For a long time, phase contrast imaging has been restricted to synchrotron radiation sources or special techniques due to requirement of spatial coherence of radiation. Along with recent development of X-ray micro and nanofocus tubes and X-ray detectors a phase contrast imaging becomes available also with laboratory sources. In this work an overview of phase contrast imaging methods is given, with an emphassis on propagation based method. Examples of this method and application of phase retrieval algorithm on samples from RIGAKU Nano3DX and GE phoenix v|tome|x L240 stations within Laboratory of X-ray micro and nanotomography CEITEC BUT are shown.
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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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Object Speed Measuring Using The Fourier Transform
Zikmund, Tomáš ; Martišek, Karel (referee) ; Štarha, Pavel (advisor)
This work deals with object speed measuring using image analysis method. The reader will become familiar with a mathematical theory upon which the method is based. The mathematical algorithm for obtaining the speed of a given object is illustrated. Furthermore, an original computer program has been developed and the results of real measuring are shown.
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