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1

Factors Influencing Accuracy of Estimating Position of Objects in a Multi-camera System

Klimaszewski Krzysztof, Grajek Tomasz, Wegner Krzysztof

Journal of Telecommunications and Information Technology

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2024

|

nr 2

1--16

EN

Nowadays, research focusing on robotics, autonomous vehicles, and scene analysis shows a clear need for the ability to accurately reconstruct three-dimensional environments. One of the methods allowing to conduct such a reconstruction is to use a set of cameras and image processing techniques. This is a passive method. Despite being, in general, less accurate than its active counterparts, it offers significant advantages in numerous applications in which active systems cannot be deployed due to limited performance. This paper provides a theoretical analysis of the accuracy of estimating 3D positions of objects present at a given scene, based on images from a set of cameras. The analysis assumes a known geometrical configuration of the camera system. The important limiting factor in the considered scenario is the physical resolution of sensors - especially in the case of systems that are supposed to work in real time, with a high FPS rate, as the use of high-resolution cameras is difficult in such circumstances. In the paper, the influence of the geometric arrangement of the cameras is studied and important conclusions about the potential of three-camera configurations are drawn. The analysis performed and the formulas derived help predict the boundary accuracy values of any system using a digital camera. The results of an experiment that confirm the theoretical conclusions are presented as well.

2

Three-Dimensional Freehand Ultrasound Strain Elastography Based on the Assessment of Endogenous Motion: Phantom Study

Sakalauskas Andrius, Jurkonis Rytis, Lukoševičius Arūnas

Archives of Acoustics

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2023

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Vol. 48, No. 2

219--229

EN

The purpose of this paper is to present the results of the pilot experiments demonstrating proof of concept of three-dimensional strain elastography, based on freehand ultrasound for the assessment of strain induced by endogenous motion. The technique was tested by inducing pulsatility in an agar-based tissue mimicking phantom with inclusions having different stiffness and scanning the 1D array with an electromagnetic position sensor. The proof of concept is explored with a defined physical phantom and the adopted algorithm for strain analysis. The agar-based phantom was manufactured with two cylindrical inclusions having different stiffness (7 kPa and 75 kPa in comparison to the background 25 kPa) and scattering properties. The internal strain in the phantom was introduced by mimicking a pulsating artery. The agar mixture displacements were estimated by using the GLUE algorithm. The 3D isosurfaces of inclusion from rendered volumes obtained from the B-mode image set and strain elastograms were reconstructed and superimposed for a quantitative comparison. The correspondence between the B-mode image-based inclusion volume and the strain elastography-based volume was good (the Jaccard similarity coefficient in the range 0.64–0.74). The obtained results confirm the 3D freehand endogenous motion-based elastography as a feasible technique. The visualization of the inclusions was successful. However, quantitative measurements showed that the accuracy of the method in volumetric measurements is limited.

3

The Use of 3D Imaging in Surface Flatness Control Operations

Sioma Andrzej, Karwat Bolesław

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 6

335--344

EN

The paper presents a surface flatness control system designed for installation on a production line. Such a system allows the control of all blanks leaving the production line in terms of measuring flatness made in the conditions prevailing on the production line. The article discusses 3D imaging methods enabling the construction of a surface image. An analysis of imaging parameters for each method is presented. For the selected imaging method, an analysis of the imaging resolution is presented. An example of flatness measurement for a selected element after a welding operation is shown. The flatness measurement algorithm is discussed, and the results of measurements are presented. The results of measurements for selected two product groups are presented.

4

Simultaneous intensity projection for projector response computation with application to an active radiometric calibration

Filio-Aguilar Pedro-David, López-García Lourdes, Rueda-Paz Juvenal, Ávila-Aoki Manuel

Optica Applicata

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2022

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Vol. 52, nr 4

521--533

EN

One of the most important sources of errors in digital fringe projection (DFP) systems is the nonlinearity in the response of the projector when it uses the three-step phase retrieval algorithm. Thus, it is necessary to increase the accuracy without affecting the efficiency. In this sense, the radiometric rectification methods are used. In this paper, an active radiometric rectification method for digital fringe projection is proposed. This proposal consists in two improvements of traditional active techniques: first, parallel intensity projection is used to obtain the projector response which requires only four dot patterns; and second, a method is provided for the calculation of the inverse polynomial that guarantees symmetry with respect to the response of the projector. Experimental results, in a digital fringe projection system, show that the root-mean-square phase error improves 6.3 times using this proposal.

5

Comparison of Lugol's solution and Fe3O4 nanoparticles as contrast agents for tumor spheroid imaging using microcomputed tomography

Panek Dominik, Szczepanek Monika, Leszczyński Bartosz, Moskal Paweł, Stępień Ewa Ł.

Bio-Algorithms and Med-Systems

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2022

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Vol. 18, no. 1

158--162

EN

Background Lugol’s solution is well known for its unique contrasting properties to biological samples in in microcomputed tomography imaging. On the Rother hand, iron oxide nanoparticles (IONPs), which have much lower attenuation capabilities to X-ray radiation show decent cell penetration and accumulation properties, are increasingly being used as quantitative contrast agents in biology and medicine. In our research, they were used to stain 3D cell structures called spheroids. Aim In this study, the micro computed tomography (µCT) technique was used to visualize and compare the uptake and accumulation of two contrast agents, Lugol’s solution and iron (II, III) oxide nanoparticles (IONPs) in the in vitro human spheroid tumour model. Methods The metastatic human melanoma cell line WM266-4 was cultured, first under standard 2D conditions, and after reaching 90% confluence cells was seeded in a low adhesive plate, which allows spheroid formation. On the 7th day of growth, the spheroids were transferred to the tubes and stained with IONPs or Lugol’s solution and subjected to µCT imaging. Results Our research allows visualization of the regions of absorption at the level of single cells, with relatively short incubation times - 24h - for Lugol’s solution. IONPs proved to be useful only in high concentrations (1 mg/ml) and long incubation times (96h). Conclusions When comparing the reconstructed visualizations of the distribution of these stating agents, it is worth noting that Lugol’s solution spreads evenly throughout the spheroids, whereas IONPs (regardless of their size 5 and 30 nm) accumulate only in the outer layer of the spheroid structure.

6

Zastosowanie mikrotomografii rentgenowskiej do trójwymiarowej analizy obrazu systemu powłokowego antygraffiti

Gądek-Moszczak Aneta, Radek Norbert, Pasieczyński Łukasz, Szlązak Karol

Przemysł Chemiczny

|

2019

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T. 98, nr 4

621--624

PL

Przedstawiono przykładowe możliwości zastosowania obrazowania 3D mikrotomografii komputerowej do analizy systemu powłokowego antygraffiti. Analiza jakościowa zrekonstruowanych obrazów 3D umożliwiła ocenę jednorodności rozmieszczenia porowatości w materiale pośrednim, jak również ocenę spójności warstwy nawierzchniowej z podłożem. Analiza ilościowa obejmowała wyznaczenie porowatości materiału oraz rozmiaru porów (wyrażonego za pomocą objętości porów w μm³), a także wyznaczenie rozkładu grubości warstwy nawierzchniowej wzdłuż wirtualnego przekroju poprzecznego próbki.

EN

An anti-graffiti coating system with a layer thickness of about 100 mm³ was applied on a cuboid-sized steel sample (3×3.86×10 mm). The porosity of the intermediate layer and the thickness of the topcoat were detd. The av. pore vol. was about 1.125·10⁶ μm³ and thickness of the topcoat was 97.98-103.78 μm. The X-ray microtomography was recommended for 3D anal. of coatings as it provides valuable information about their porosity.

7

Spatiotemporal multiplexing method for visual field of view extension in holographic displays with naked eye observation

Finke G., Kujawińska M., Kozacki T., Zaperty W.

Opto-Electronics Review

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2016

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Vol. 24, No. 3

117--125

EN

In this paper we propose a method which allows to overcome the basic functional problems in holographic displays with naked eye observation caused by delivering too small images visible in narrow viewing angles. The solution is based on combining the spatiotemporal multiplexing method with a 4f optical system. It enables to increase an aperture of a holographic display and extend the angular visual field of view. The applicability of the modified display is evidenced by Wigner distribution analysis of holographic imaging with spatiotemporal multiplexing method and by the experiments performed at the display demonstrator.

8

Development of a high-resolution real-time-capable 3D SONAR camera for deep sea operation

Ehrhardt M., Becker F. J., Speicher D., Fonfara H., Hewener H., Degel C., Tretbar S.

Hydroacoustics

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2016

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Vol. 19

101--110

EN

Within this work we present a first experimental setup of a high-resolution real-timecapable 3D sonar camera system for deep sea operation. Since we are currently in the development process, the focus of this work is on the transmission aspects of the camera. Following publications will include the receiving aspects as well as the first phantom reconstructions. The system consists of a 1024 element matrix array antenna, together with a 128 channel beamforming system including a 1:8 multiplexing device for each channel. The camera is supposed to deliver volumetric images within a range of up to 15 m in a deep sea environment up to 6000 m depth. The antenna provides the advantage of an adjustable defocused transmitting sound field. This allows dynamic control of the field of view, and an increase of the image contrast for a specific region.

9

The three-dimensional imaging of rock wall surface with the use of computer-based image processing and analysis

Oleszko K., Młynarczuk M.

Studia Geotechnica et Mechanica

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2015

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Vol. 37, nr 1

53--58

EN

The paper presents two methods of digital mapping of rock walls in three dimensional space. The methods have been developed with the use of low-cost devices, which enable image acquisition, and processing methods based on digital image processing and analysis. Both methods are based on so-called shadow profilometry. One of those methods involved mapping the shape of the rock wall on casted mapped surface with analyzed laser lines. The second method was based on the analysis of projected set of bit planes. The planes were projected by computer projector. Both measurement methods have been tested in Miękinia porphyry quarry. The study involved rock wall measurements, which were repeated several times. The part of rock material was removed from the measured wall after each measurement. In order to verify the accuracy of the proposed methods of measurement, volume results obtained and based on digital methods were compared to the volume of removed rock material during measurement. Calculated results were characterized by small deviations which prove to be correct, and are a solid basis for further work on practical application of presented methods.

10

Technologie ciekłokrystaliczne na tle współczesnych technik zobrazowania 3D powszechnego użytku

Mazur R., Piecek W., Węgłowska D., Dąbrowski R.

Elektronika : konstrukcje, technologie, zastosowania

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2014

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Vol. 55, nr 10

93-96

PL

W ostatnich latach obserwuje się dynamiczny rozwój technologii dostarczenia widzom zobrazowania przestrzennego, tzw. zobrazowania 3D. Obecnie na rynku możemy wyróżnić dwie podstawowe grupy metod pozwalających uzyskać zobrazowanie 3D. Pierwszą z nich jest stereoskopia, do której zalicza się metody wykorzystujące specjalne okulary. Druga to autostereoskopia, skupiająca techniki bezokularowe. Metoda uzyskania zobrazowania 3D, oparta na wykorzystaniu okularów aktywnych jest technologią dominującą dla będących obecnie w sprzedaży odbiorników telewizyjnych wspierających technologię 3D. Ma ona jednak wiele wad wynikających z zastosowanych w okularach aktywnych przetworników ciekłokrystalicznych i efektów elektrooptycznych, na których one bazują (efekt TN). Dzięki zastosowaniu nowych materiałów ciekłokrystalicznych do obecnie stosowanych efektów elektrooptycznych możliwa jest poprawa parametrów okularów aktywnych i ograniczenie niektórych ich wad. Jako ciekawa alternatywa dla klasycznych efektów elektrooptycznych, stosowanych w okularach aktywnych 3D, przejawia się efekt rozpraszający oparty na wymuszonym za pomocą pola elektrycznego przejściu fazowym cholesteryk– nematyk.

EN

In recent years we can observe the rapid development of technologies to provide viewers spatial imaging, so-called 3D imaging. Currently on the market we can distinguish two main groups of 3D imaging methods. The first is stereoscopy, which include methods using special glasses. The second is autostereoscopy, gathering techniques without glasses. The method for 3D imaging, based on the using of active glasses is dominant now for displays that support 3D technology. However, it has many disadvantages resulting from the using of liquid crystal active glasses transducers and electro-optical effects, on which they are based (TN effect). By using of new materials for currently used liquid crystal electro-optical effects is possible to improve the parameters of active glasses and limit some of their disadvantages. As an interesting alternative to the classical electro-optical effects applied in 3D active glasses, manifests itself dispersion effect based on forced by the electric field cholesteric– nematic phase transition.

11

Zaawansowana analiza powierzchni próbki w mikroskopii świetlnej

Jedyński M.

Laboratorium - Przegląd Ogólnopolski

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2013

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nr 3-4

62--63

PL

Szybki postęp we współczesnej mikroskopii świetlnej wymusza stosowanie coraz bardziej wyrafinowanych technik służących nie tylko do samej wizualizacji dwuwymiarowej, ale również zaawansowanej analizy pozwalającej uzyskiwać więcej informacji o badanych obiektach. Najnowocześniejszym rozwiązaniem dedykowanym tym celom jest moduł mikroskopowy PhaseView, umożliwiający w prosty sposób rozbudowę dowolnego mikroskopu pracującego w technice jasnego pola o szereg nowych funkcjonalności.

EN

Fast advancement in the field of modern optical microscopy implicates application of more sophisticated techniques used not only for aquisition of two-dimensional images but also for advanced image and surface analysis leading to obtaining more information about object to be analyzed. The state-of-the-art solution dedicated to these purposes in PhaseView microscope module for any existing optical microscope working in the bright field that enables users to apply many new funcionalites.

12

System detekcyjny elektronów wtórnych I wstecznie rozproszonych do obrazowania 3D w niskopróżniowej SEM

Słówko W., Krzysztof M.

Elektronika : konstrukcje, technologie, zastosowania

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2012

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Vol. 53, nr 2

34-36

PL

Przedstawiono nowe rozwiązanie systemu detekcyjnego, przeznaczonego do kierunkowej detekcji elektronów w niskopróżniowej skaningowej mikroskopii elektronowej, w celu trójwymiarowej (3D) rekonstrukcji topografii powierzchni metodą wielodetektorową. Kluczowym zespołem systemu jest głowica próżniowo-detekcyjna, stanowiąca komorę pośrednią układu pompowania różnicowego, w której wnętrzu zainstalowano czterokwadrantową diodę PIN jako detektor elektronów wstecznie rozproszonych (BSE). Rolę detektora elektronów wtórnych (SE) typu jonizacyjnego, pełni przesłona dławiąca przepływ gazu. Pokazano, że w dyskutowanym rozwiązaniu można uzyskać kierunkową detekcję BSE, niezakłóconą w skutek rozpraszania w gazie jak i detekcję SE w szerokim zakresie ciśnień.

EN

A new system for directional detection of electrons in low vacuum scanning electron microscopy (LVSEM) is presented. The system is destined for three dimensional (3D) reconstruction of the surface topography with the multi detector method. A main unit of the system is the vacuum-detection head playing the role of an intermediate chamber of the differential vacuum system and containing a four-quadrant PIN diode as the backscattered electron (BSE) detector. The role of a secondary electron (SE) detector of the ionization type is performed by the aperture throttling gas flow. Authors show that both the directional BSE detection undisturbed by scattering and SE detection can be obtained in a wide range of gas pressures.

13

Wpływ próby ściskania na zmianę struktury beleczkowej kości – ilościowy opis mikrostruktury z wykorzystaniem metod obrazowania 3D

Sobuś M., Iwaniec M., Gądek-Moszczak A., Łagan S.

Aktualne Problemy Biomechaniki

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2012

|

z. 6

129--134

PL

Celem niniejszej pracy była analiza zdjęć mikrotomograficznych kręgów L3. Wyznaczono parametry histomorfometryczne kości beleczkowych kręgów pochodzących od kobiet w różnym wieku, przed oraz po wykonaniu próby ściskania. Dokonano analizy porównawczej parametrów w celu wyłonienia elementów struktury najbardziej podatnych na degradację.

14

Trójwymiarowa rekonstrukcja powierzchni w SEM z zastosowaniem półprzewodnikowego detektora elektronów wstecznie rozproszonych

Słówko W., Jeziorski Ł., Krysztof M.

Elektronika : konstrukcje, technologie, zastosowania

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2011

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Vol. 52, nr 11

53-55

PL

Przedstawiono system przeznaczony do trójwymiarowej (3D) rekonstrukcji powierzchni w skaningowym mikroskopie elektronowym (SEM), złożony z kwadrupolowego detektora półprzewodnikowego elektronów wstecznie rozproszonych, czterokanałowego sytemu cyfrowej akwizycji sygnałów i systemu przetwarzania opartego na komputerze klasy PC. Autorzy zastosowali tu metodę wykorzystującą specyficzny rozkład kątowy elektronów wstecznie rozproszonych na powierzchni próbki. Algorytmy przetwarzania sygnałów związane z procesem rekonstrukcji powierzchni zostały uzupelnione o procedury kompensacji błędów metody. Dzięki temu, po wstępnej kalibracji, system pozwala odtworzyć topografię powierzchni z dokładnością lepszą niż 10%, jeśli nachylenia nie przekraczają 60°. Pozwala także na odtworzenie kształtu bardzo gładkich powierzchni i może działać bardzo szybko, niemal w "czasie rzeczywistym" dostarczając informacji o kształcie powierzchni obiektów niezależnie od ich składu materiałowego.

EN

A 3D surface reconstruction system for SEM consisting of a quadruple semiconductor detector of backscattered electrons, a four-channel framegrabber and PC-based processing unit, is presented. The authors explored a method that takes advantage of the angular distribution of backscattered electrons to obtain quantitative topography contrast and visualise the surface shape. Software processing algorithms were developed to carry out the reconstruction process and compensate several types of errors, inherent in the method. After pre-calibration, the system allows to obtain surface topography with accuracy better than 10% when maximum slope angles are below 60°. It is also capable to reconstruct the shapes of very smooth surfaces and can operate very quickly, almost in real-time, providing reliable, composition-independent reconstructions for a broad class of materials.

15

Finite element modelling of the articular disc behaviour of the temporo-mandibular joint under dynamic loads

Jaisson M., Lestriez P., Taiar R., Debray K.

Acta of Bioengineering and Biomechanics

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2011

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Vol. 13, no. 4

85-91

EN

The proposed biodynamic model of the articular disc joint has the ability to affect directly the complete chewing mechanism process and its related muscles defining its kinematics. When subjected to stresses from the mastication muscles, the disc absorbs one part and redistributes the other to become completely distorted. To develop a realistic model of this intricate joint a CT scan and MRI images from a patient were obtained to create sections (layers) and MRI images to create an anatomical joint CAD model, and its corresponding mesh element using a finite element method. The boundary conditions are described by the external forces applied to the joint model through a decomposition of the maximum muscular force developed by the same individual. In this study, the maximum force was operating at frequencies close to the actual chewing frequency measured through a cyclic loading condition. The reaction force at the glenoid fossa was found to be around 1035 N and is directly related to the frequency of indentation. It is also shown that over the years the areas of maximum stresses are located at the lateral portion of the disc and on its posterior rim. These forces can reach 13.2 MPa after a period of 32 seconds (s) at a frequency of 0.5 Hz. An important part of this study is to highlight resilience and the areas where stresses are at their maximum. This study provides a novel approach to improve the understanding of this complex joint, as well as to assess the different pathologies associated with the disc disease that would be difficult to study otherwise.

16

Monitoring of solids behaviour during gravitional flow in rectangular silo

Niedostatkiewicz M., Chaniecki Z., Grudzień K., Romanowski A., Banasiak R., Betiuk J.

Zeszyty Naukowe. Elektryka / Politechnika Łódzka

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2009

|

z. 114

63-68

EN

This paper is focused on the application of Electrical Capacitance Tomography (ECT) to gravitational flow of bulk solid in rectangular silo investigation. In order to measure the materials distribution inside a vessel, a dedicated, spatial 16 electrode sensor is designed. Reconstructed images are presented in 3D domain space. The investigated silo model consists of rectangular bin and a cone-like hopper section. The flow behaviour of material (friable sand) is studied for two silo model configurations having different lower section slopes. The slope angle is a silo geometrical parameter affecting the type of the flow regime - mass or funnel type.

17

A PXI-based electrical impedance tomography system for industrial use

Kourunen J., Savolainen T., Lehikoinen A., Vauhkonen M., Heikkinen L. M.

Zeszyty Naukowe. Elektryka / Politechnika Łódzka

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2009

|

z. 114

69-74

EN

A design of an electrical impedance tomography system for three-dimensional and real-time imaging of ndustrial processes is described. The system is based on modular and easily extended PXI platform. In this case, the system consists of 16 parallel current injection channels and 80 parallel voltage measurement channels. The maximum of the frame rate of the system is about 100 frames/second depending on the configuration of the system. In order to study the quality of the system several laboratory tests are performed. Furthermore, two laboratory experiments are shown to verify the performance of the whole system.

18

Scanning Acoustic Microscope for 3D imaging

Dynowski K., Litniewski J., Nowicki A.

Archives of Acoustics

|

2008

|

Vol. 33, No. 3

293-302

EN

A new Acoustic Microscope operating at the frequency up to 200 MHz and allowing for visualization of the internal structures of materials was developed. The system was built basing on the commercially available components and the self-designed acoustic lenses. The dedicated software was developed to control the process of 3D RF-data acquisition, processing and presenting in 2D cross-sections or 3D surface rendering mode. This article describes the technical principles of the constructed microscope and presents the reconstructed images of the designed test-probe and of the integrated circuit.

19

Trójwymiarowe obrazowanie powierzchni w skaningowym mikroskopie elektronowym

Paluszyński J., Słówko W.

Elektronika : konstrukcje, technologie, zastosowania

|

2006

|

Vol. 47, nr 4

26-28

PL

Przedstawiono zasadę działania i budowę systemu służącego do syntezy trójwymiarowych obrazów topografii powierzchni otrzymywanych w skaningowym mikroskopie elektronowym (SEM). Synteza obrazu trójwymiarowego wykorzystuje właściwości rozkładu kątowego elektronów wtórnych i wstecznie rozproszonych. Układ czterech scyntylacyjnych detektorów elektronów wtórnych jest źródłem sygnałów zależnych od lokalnego nachylenia analizowanej powierzchni. Układ akwizycyjny przetwarza te sygnały na postać cyfrową i transmituje do komputera klasy PC, gdzie są zapamiętywane w formie czterech obrazów dwuwymiarowych, różniących się kierunkiem oświetlenia badanego obiektu. Specjalne oprogramowanie realizuje algorytm syntezy trójwymiarowej.

EN

A system for quantitative three-dimensional synthesis of surface topography for a scanning electron microscope (SEM) is presented. The three-dimensional image synthesis is based on the angular distribution of secondary and backscattered electrons. A quadruple secondary electron detector unit allows obtaining signals dependent on local surface inclination. An acquisition unit converts these signals to their digital form and transmits them to a PC, where they are stored as four images enlighten from different directions. Special software carries out the process of the 3D imaging in many possible manners. Errors and potential applications of the method are also discussed.

20

X-ray tomography imaging: a necessary tool for materials science

Babout L.

Automatyka / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

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2006

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T. 10, z. 3

117-124

EN

This paper gives an overview on different examples of X-ray tomography applications in the field of materials science. It highlights the necessity of applying the technique to investigate scientific problem which cannot be solved with conventional imaging tools.

PL

Artykuł przedstawia przegląd rozmaitych zastosowań tomografii rentgenowskiej w dziedzinie materiałoznawstwa. Podkreśla konieczność zastosowania tej techniki w celu rozwiązywania problemów naukowych, które nie mogą być wyjaśnione za pomocą typowych narzędzi obrazowania.