Academic literature on the topic 'Geometrická kalibrace'

Magnetometer memiliki kemampuan untuk mendeteksi objek logam (besi) dengan tingkat deteksi yang berbeda tergantung sensitivitas dan akurasinya. Kalibrasi merupakan salahsatu cara dalam menentukan daya deteksi dari sebuah magnetometer dimana hasilnya dapat digunakan dalam desain survei pendeteksian ranjau. Data hasil kalibrasi yang digunakan dalam paper ini adalah kalibrasi terhadap magnetometer Geometrics G-877. Prosedur kalibrasi dilakukan dengan cara melewatkan objek logam besi batangan pada 5 lintasan dengan jarak lintasan berbeda masing-masing 2, 3, 4, 5, dan 6 meter terhadap sensor magnetometer. Hasil kalibrasi menunjukan bahwa kemampuan deteksi sampai 5 m dilihat dari respon anomali magnetnya. Sehingga untuk desain survei dengan menggunakan 2 sensor magnet yang sejenis maka spasi lintasan 10 m dan jarak masing-masing sensor 2 m sementara kedalaman sensor dipertahankan 1 meter di atas dasar laut. Kata Kunci: magnetometer, kalibrasi, variasi harian. Magnetometer has ability to detect metal object (iron) with different level of detection, that depend on its sensitivity and accuracy. Calibration is one way in determine detection level of magnetometer where this procedure can be used to arrange survey design for mine detection. The result of calibration that will be used in this paper was calibration on Geometrics type G-877. Calibration procedure was done by passing plate iron object on 5 line with different distances 2,3,4,5 and 6 meters from magnetometer sensor. The result show that detection level up to 5 meters based on respond of anomaly magnetic and the survey design can be arranged in case using 2 sensor of magnetometer the line spacing will be 10 m and distance between both sensor 2 meter and depth sensor must be kept 1 meter above seabed. Keywords: magnetometer, calibration, diurnal variation.

Tato dizertace je zaměřena na medicínskou zobrazovací modalitu – ultrazvukovou počítačovou tomografii – a algoritmy zlepšující kvalitu zobrazení, zejména kalibraci USCT přístroje. USCT je novou modalitou kombinující ultrazvukový přenos signálů a principy tomografické rekonstrukce obrazů vyvíjených pro jiné tomografické systémy. V principu lze vytvořit kvantitativní 3D obrazové objemy s vysokým rozlišením a kontrastem. USCT je primárně určeno pro diagnózu rakoviny prsu. Autor spolupracoval na projektu Institutu Zpracování dat a Elektroniky, Forschungszentrum Karlsruhe, kde je USCT systém vyvíjen. Jeden ze zásadních problémů prototypu USCT v Karlsruhe byla absence kalibrace. Tisíce ultrazvukových měničů se liší v citlivosti, směrovosti a frekvenční odezvě. Tyto parametry jsou navíc proměnné v čase. Další a mnohem závažnější problém byl v pozičních odchylkách jednotlivých měničů. Všechny tyto aspekty mají vliv na konečnou kvalitu rekonstruovaných obrazů. Problém kalibrace si autor zvolil jako hlavní téma dizertace. Tato dizertace popisuje nové metody v oblastech rekonstrukce útlumových obrazů, kalibrace citlivosti měničů a zejména geometrická kalibrace pozic měničů. Tyto metody byly implementovány a otestovány na reálných datech pocházejících z prototypu USCT z Karlsruhe.

Work deals with methods of calibration of multi-center study of magnetic resonance imaging. Magnetic resonance is the phenomenon of the substance in a magnetic field of induction B0 delivers energy in the form of RF pulse with the Larmor frequency and thus to excite particles to higher energy levels. Calibration can be performed using the distinctive and homogeneous RF phantoms. Furthermore, we can perform calibration using image registration. To calibrate the images by registering the work described in the classical linear (affine) and nonlinear. Listed below are the simulators, which are also useful for modeling various artifacts.

The aim of this work is description of a device developed at Brno University of Technology, Faculty of Civil Engineering, Institute of Geodesy for the purpose of absolute calibration of geodetic GNSS antennas. Thanks to calibration it is possible to remove systematic error of antenna's phase centre. The device consists of moveable arm and processing unit. The moveable arm is able to set up calibrated antenna to required azimuth and elevation angle. This work introduces the issue of absolute calibration, describes the moveable arm and the process of its assembling. Further, it defines geometrical parameters of moveable arm, describes their determination and their independent verification by geodetic method. Finally, the model of movement of antenna's reference point is described.

This diploma thesis solves the analysis of the influence of calibration and the method of strips alignment on the geometric accuracy of a point cloud acquired by UAV lidar scanning. The aim was to find out the influence of individual used methods, respectively various combinations. The effect of the design of the cross-flights has also been added. The evaluation was performed using standard deviations of the distances corresponding to the areas scanned in different point bands. Furthermore, verification was performed by comparing checkpoints. The results show that there is no dependence between the individual combinations. The only case was a larger displacement of the point cloud at the edge of the scanned strip in the case of cross-flights.