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Real Time Suppression of Atmospheric Turbulence
Macků, Jiří ; Orság, Filip (referee) ; Marvan, Aleš (advisor)
This paper deals with removing undesirable image deformations caused by turbulences of Earth's atmosphere. The goal is to design and implement algorithm for suppression of atmosphere turbulence in video sequences to use in long-distance camera monitoring system. This paper also focuses on optimization of existing algorithms for running in real-time. Algorithm will be implemented in C++ programming language with use of library for computer vision OpenCV.
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Influence of atmospheric turbulences on laser beam intensity profile
Císař, David ; Wilfert, Otakar (referee) ; Hudcová, Lucie (advisor)
Free space optical communications provide a reliable alternative to microwave and cable system applications. This technology is utilized for an optical links between ground stations, and moreover for links between High Altitude Platforms (HAPs). The main goal of the project is to gather knowledge about degradation of an optical beam in the atmosphere. The optical beam is being exposed to many factors such as intensity fluctuation based on turbulence, attenuation due to absorption and scattering. Furthermore, an emergence and influence of the atmospheric turbulences on the intensity profile of the laser beam are discussed. At the end, the methods of atmospheric turbulence measurement are given.
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Communication protocols for Free-Space Optical links
Šedo, Ondrej ; Kincl, Zdeněk (referee) ; Kolka, Zdeněk (advisor)
This master’s thesis is focused on behaviour of the TCP/IP protocol on free-space optical link which is affected by the effect of atmospheric turbulence. This causes fluctuation of the received optical power and therefor bit error rate changes. In the simulation model short-time bit error rate is calculated from random generated received optical signal and then used in time-domain analysis of the OMNeT++ network simulator. A buffer in transmitter is designed based on simulation results. It pauses the data transmitting in cases of FSO link outage. This method is then implemented into FPGA device.
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Power Budget of the Laser Rangefinder
Kotol, Martin ; Němeček, Jiří (referee) ; Wilfert, Otakar (advisor)
The thesis analyzes the optical laser range finders in real propagation environments. Itdescribes the various parts of optical laser range finders their properties and principles in relation to their performance balance. The paper presents the basic optical properties of lenses used in the transmitter and receiver. A separate chapter is devoted to the transit time method and factors influencing the measurement. The proportional directional reflectance analysisis a part of the thesis. In conclusion, the thesis contains the practical laboratory measurements of the relative directional reflectance of different materials and colors, and verification of the power level diagram.
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Model of atmospheric transmission media for free space optics
Přikryl, Petr ; Vlček, Čestmír (referee) ; Wilfert, Otakar (advisor)
The aim of this thesis is to study the methods of a free space optical link design and its application in the communication technologies. The thesis describes possible intrusive influences on the transmitted optical signal, which are the signal noise, atmospheric attenuation and atmospheric turbulences. The thesis is particulary focused on the influence of the atmospheric turbulences and atmospheric attenuation on the optical beam.
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The distribution of relative variance of optical intensity in laser beam
Barcík, Peter ; Coufalíková,, Aneta (referee) ; Hudcová, Lucie (advisor)
This master´s thesis provides basic properties and measurement of optical beams. In the first chapter is shown division of light on ray, wave and beam optics. Atmospheric optics and properties associated with propagation of light through the earth's atmosphere is presented in the second chapter. In the third part are shown basic techniques for Gaussian beam shaping. The last chapter deals with measurement of optical beam after propagating through a turbulent medium. In this section is shown distribution of relative variance of optical intensity in Gaussian and Top-Hat beam. There is also measured spatial coherence of laser beam in the turbulent atmospheric transmission media. Finally effect of the beam wander is investigated.
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Laser beam coherence in turbulent atmosphere
Polanský, David ; Drexler, Petr (referee) ; Hudcová, Lucie (advisor)
In the first part of the thesis discusses the function of the laser design and construction of its class. Here is an explanation of coherence and other properties of laser radiation. Listed below are the possibilities of energy distribution in the laser beam. Described in particular Gaussian beam. The paper explains the phenomena of bending and Young's experiment. The paper examines the influence of atmospheric environment in the transmission of electromagnetic waves, defined as light. Particular attention is devoted to atmospheric turbulence. In the second part are first discussed the possibility of measuring atmospheric turbulence and coherence of laser beam parameters. The following is designed to measure workplace coherence width and coherence length in a turbulent environment. At these workplaces were measured. The results of these measurements are also listed in the job. The following comparison of results with theoretical values.
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Influence of atmospheric turbulences on the optical beam
Bárta, Miroslav ; Wilfert, Otakar (referee) ; Hudcová, Lucie (advisor)
The aim of this thesis is to study a free space optics and its application in communication technologies. It describes possible interrupting impacts on the beamed optical signal, which are signal noise, attenuation of the atmosphere and atmospheric turbulence. The basis of the thesis is to describe the impact of the atmospheric turbulences on the optical beam. Fluctuation of optical intensity in the optical beam has been measured and index of refraction structure parameter calculated. With its assistance, turbulence rate has been determined.
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