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Laserskanning och 3Dmodellering för rekonstruktion av ett medeltida kyrkorum / Laser scanning and 3D-modeling for reconstruction of a medieval church.Wiberg, Frida, Rindberg, Agnes January 2019 (has links)
Denna studie beskriver en 3D rekonstruktion av en medeltida kyrka belägen 25 km söder om Växjö. Kyrkan som är byggd under 1200-talet är speciell då den fortfarande har kvar mycket av sitt ursprungliga utseende. Kyrkan har även en välbevarad takkonstruktion som speciellt uppmärksammas i detta arbete. Problemet är dock att konstruktionen i dagsläget är dold bakom ett senare tillbyggt undertak. Syftet och målet med 3D rekonstruktionen är att återskapa kyrkorummet till sitt ursprungliga utseende och jämföra det med det nutida utifrån tre aspekter; ljusinsläpp, rumsupplevelse och rörelsemöjligheter. Resultatet av projektet visade att kyrkorummet var mycket mörkare förr på grund av att endast ett fåtal mindre fönster fanns. Kyrkorummet var däremot mer öppet under 1200-talet då det troligtvis inte fanns någon inredning i kyrkan, samt att det var öppet upp till nock innan undertaket byggts till. Idag har kyrkan fler och större fönster och den är även inredd med bänkar utmed långsidorna, vilket har påverkat rörelsemönstret. Framtida projekt som handlar om äldre kyrkor och konstruktioner kommer att kunna använda studien. Detta genom att behandla den som en riktlinje samt ett stöd för sitt projekt. Denna studien kan också ligga till grund för vidare och mer fördjupande studier inom detta område, då 3D-modellen kan användas till bland annat VR-teknik. Användning av VR-teknik kan möjliggöra för människor att uppleva det ursprungliga kyrkorummet precis som om de vore på plats. / This study is describing a 3D reconstruction of a medieval church located 25 kilometers south of Växjö. The church is very special as the appearance of the building is still very original. The church also has an unusual roof construction that this project wants to point out. However, the roof structure once visible from the church room, is today hidden by a ceiling which was erected later in an indefinite time. The purpose and goal with the 3D reconstruction is to recreate the original church hall and compare it with the contemporary interior design based on three aspects; experiences of light, - the room in general and the experiences of movement patterns in the church. The result of the project showed that the church hall earlier on was much darker inside due to the lack of windows, but the church hall was on the other hand very spacious in the middle ages because the interior was not furnished during this time. Today the church has received more and larger windows and the hall is furnished with pews and a pulpit, which have led the movement pattern to an aisle from west to east in the middle of the church hall. In future projects, about churches and older constructions, this study can be used as guideline and support for further studies. It is also a study that is open for additional development, as for example the 3D reconstruction can be translated into VRtechnology, so that people can experience the medieval church as it was in the 13th century, almost like they were there.
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Estimating 3D-trajectories from Monocular Video Sequences / Estimering av 3D-banor från monokulära videosekvenserSköld, Jonas January 2015 (has links)
Tracking a moving object and reconstructing its trajectory can be done with a stereo camera system, since the two cameras enable depth vision. However, such a system would not work if one of the cameras fails to detect the object. If that happens, it would be beneficial if the system could still use the functioning camera to make an approximate trajectory reconstruction. In this study, I have investigated how past observations from a stereo system can be used to recreate trajectories when video from only one of the cameras is available. Several approaches have been implemented and tested, with varying results. The best method was found to be a nearest neighbors-search optimized by a Kalman filter. On a test set with 10000 golf shots, the algorithm was able to create estimations which on average differed around 3.5 meters from the correct trajectory, with better results for trajec-tories originating close to the camera. / Att spåra ett objekt i rörelse och rekonstruera dess bana kan göras med ett stereokamerasystem, eftersom de två kamerorna möjliggör djupseende. Ett sådant system skulle dock inte fungera om en av kamerorna misslyckas med att detektera objektet. Om det händer skulle det vara fördelaktigt om systemet ändå kunde använda den fungerande kameran för att göra en approximativ rekonstruktion av banan. I den här studien har jag undersökt hur tidigare observationer från ett stereosystem kan användas för att rekonstruera banor när video från enbart en av kamerorna är tillgänglig. Ett flertal metoder har implementerats och testats, med varierande resultat. Den bästa metoden visade sig vara en närmaste-grannar-sökning optimerad med ett Kalman-filter. På en testmängd bestående av 10000 golfslag kunde algoritmen skapa uppskattningar som i genomsnitt skiljde sig 3.5 meter från den korrekta banan, med bättre resultat för banor som startat nära kameran.
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Structure from Motion with Unstructured RGBD DataSvensson, Niclas January 2021 (has links)
This thesis covers the topic of depth- assisted Structure from Motion (SfM). When performing classic SfM, the goal is to reconstruct a 3D scene using only a set of unstructured RGB images. What is attempted to be achieved in this thesis is adding the depth dimension to the problem formulation, and consequently create a system that can receive a set of RGBD images. The problem has been addressed by modifying an already existing SfM pipeline and in particular, its Bundle Adjustment (BA) process. Comparisons between the modified framework and the baseline framework resulted in conclusions regarding the impact of the modifications. The results show mainly two things. First of all, the accuracy of the framework is increased in most situations. The difference is the most significant when the captured scene only is covered from a small sector. However, noisy data can cause the modified pipeline to decrease in performance. Secondly, the run time of the framework is significantly reduced. A discussion of how to modify other parts of the pipeline is covered in the conclusion of the report. / Följande examensarbete behandlar ämnet djupassisterad Struktur genom Rörelse (eng. SfM). Vid klassisk SfM är målet att återskapa en 3D scen, endast med hjälp av en sekvens av oordnade RGB bilder. I djupassiterad SfM adderas djupinformationen till problemformulering och följaktligen har ett system som kan motta RGBD bilder skapats. Problemet har lösts genom att modifiera en befintlig SfM- mjukvara och mer specifikt dess Buntjustering (eng. BA). Resultatet från den modifierade mjukvaran jämförs med resultatet av originalutgåvan för att dra slutsatser rådande modifikationens påverkan på prestandan. Resultaten visar huvudsakligen två saker. Först och främst, den modifierade mjukvaran producerar resultat med högre noggrannhet i de allra flesta fall. Skillnaden är som allra störst när bilderna är tagna från endast en liten sektor som omringar scenen. Data med brus kan dock försämra systemets prestanda aningen jämfört med orginalsystemet. För det andra, så minskar exekutionstiden betydligt. Slutligen diskuteras hur mjukvaran kan vidareutvecklas för att ytterligare förbättra resultaten.
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Smooth Central and Non-Central Camera Models in Object SpaceRueß, Dominik 24 January 2024 (has links)
In den letzten Jahren sind immer mehr erschwingliche Kamera-Sensoren mit einer zunehmenden Vielfalt optischer Abbildungsfunktionen verfügbar geworden. Low-Cost-Optiken können aufgrund höherer Toleranzen und unterschiedlicher optischer Materialien von der gewünschten Lochkamera Metrik abweichen. Weitwinkel- und Fischaugenobjektive, verzerrende katadioptrische Objektive (spiegelnd und refraktiv) und andere ungewöhnliche Objektive weichen von der Annahme des Modells einer Lochkamera mit einer Brennweite ab.
Actionkameras können die gesamte Umgebung mit zwei Objektiven abbilden, diese entsprechen meist nicht mehr dem Lochkameramodell. Kameras werden auch für Messaufgaben hinter zusätzlichen optischen Elementen eingesetzt.
Die vorliegende Arbeit erweitert die ersten Erkenntnisse im Bereich der differenzierbaren (glatten) Kameramodelle ohne Einschränkungen. Viele existierende Modelle sind auf bestimmte Objektivtypen spezialisiert. In dieser Arbeit werden mehrere solcher allgemeinen Modelle eingeführt, ohne dass eine global feste Brennweite und spezielle Anforderungen an die Symmetrie der Abbildung erforderlich sind.
Eine Einführung alternativer Fehlermetriken im Objektraum bringt auch enorme Rechenvorteile, da eine Abbildungsrichtung analytisch berechnet und viele der Berechnungsergebnisse konstant gehalten werden können.
Zur Initialisierung solcher Modelle wird in dieser Arbeit eine generische lineare Kamera vorgestellt. Das wesentliche Merkmal dabei ist eine künstliche Transformation in höhere Dimensionen, welche mit linearen Verfahren weiterverwendet werden. Sie modellieren bereits nichtlineare Verzerrungen und Asymmetrien. Eine Multikamera-Kalibrierungssoftware wird ebenfalls beschrieben und implementiert.
Das Ergebnis der Arbeit ist ein theoretischer Rahmen für glatte Kameramodelle im Objektraum selbst – anstelle der Abbildung in den Bildraum – mit mehreren konkreten Modellvorschlägen, Implementierungen und dem angepassten und erweiterten Kalibrierungsprozess. / In recent years, more and more affordable camera sensors with an increasing variety of optical imaging features have become available. Low-cost optics may deviate from the desired pinhole metric due to higher tolerances and different optical materials. Wide-angle and fisheye lenses, distorting catadioptric lenses (specular and refractive) and other unusual lenses deviate from the single focal pinhole camera model assumption, which is sometimes intentional.
Action cameras can map the entire environment using two lenses, these usually no longer correspond to the pinhole camera model. Cameras are also used for measuring tasks behind additional optical elements – with unforeseeable deviations in the line of sight.
The present work expands the first findings in the field of differentiable (smooth) camera models without constraints. Many existing models specialise in certain types of lenses. In this work, several such general models are introduced without requiring fixed global focal length and symmetry requirements.
An introduction of alternative error metrics in the object space also gives enormous computational advantages, since one imaging direction can be calculated analytically and many of the calculation results can be kept constant.
For the generation of meaningful starting values of such models, this work introduces a generic linear camera. The essential feature of is an artificial transformation into higher dimensions. These transformed coordinates can then continue to be used with linear methods. They already model non-linear distortions and asymmetries. A multi-camera calibration software that efficiently implements these models is also described and implemented.
The result of the work is a theoretical framework for smooth camera models in the object space itself - instead of the established mapping into the image space - with several concrete model proposals, implementations and the adapted and extended calibration process.
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Craniogenetische Untersuchungen an Macroscelidea (Butler, 1956) (Mammalia: Afrotheria)Ihlau, Jan 29 June 2011 (has links)
An Hand einer Reihe Ontogenesestadien konnte die Entwicklung ausgewählter Bereiche des Schädels von Macroscelides proboscideus dargestellt werden. Die Befunde der Craniogenese vom Macroscelides proboscideus wurden mit Elephantulus spec., anderen Macroscelidea und Orycteropus afer verglichen. In der vorliegenden Arbeit wurden bisher nicht beschriebene Synapomorpien der Macroscelidea dargestellt, die einen Beitrag zur Erstellung des Grundmusters dieser Gruppe leisten. Es konnten folgende Befunde erhoben werden: Bei Macroscelides proboscideus wurde ein bisher nur bei Elephantulus brachyrhynchus und Elephantulus myurus beschriebener Knorpel gefunden: diese Cartilago lateralis dient bei Macroscelides proboscideus als rostraler Ursprung des Musculus maxillo-labialis ventralis. Wird dieser Befund für weitere Vertreter der Sengis bestätigt, könnte es sich um eine Autapomorphie der Macroscelidea handeln. Ein fehlender Processus postorbitalis des Frontale scheint für Macroscelides proboscideus abgeleitet zu sein. Das Foramen subopticum, das bei den Orycteropodidae fehlt, ist eine Apomorphie der Sengis. Die eindeutig basale Position der Macroscelidea innerhalb des Stammbaums der Afrotheria, die auf wenigen Fossilien gestützte phylogenetische Entwicklung, die bis heute nicht geklärten intrafamiliären Beziehungen innerhalb der Macroscelididae und die fehlenden cranialen Apomorphien der Afrotheria lassen viel Raum für weitergehende vergleichende Untersuchungen. Es wurden histologische Schnittserien digital fotografiert und als Grundlage für eine computergestützte 3D-Rekonstruktion verwendet, so dass ein digitales 3D-Modell eines Stadiums der Sengis für Vergleichszwecke vorliegt. / Sengis (formerly known as elephant shrews) represent a monophyletic group within Afrotheria. An ontogenetic study on cranial development was conducted by histological slicing 7 individuals of Macroscelides proboscideus and Elephantulus spec. Through the development of an computer aided 3D- computer model following aspects could be found: The Cartilago lateralis, a separate cartilage holding the rostral beginning of the Musculus maxillo-labialis ventralis could be described for two species of Sengis and might turn out to be a cranial autapomophie for Macroscelidea. The in Oryctepodiadae missing Foramen subopticum is present in all Sengis. The basal position of Sengis within Afrotheria and the still missing cranial Apomorphies for the Afrotheria leave much space for further discussions.
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Spindle organization in three dimensionsMüller-Reichert, Thomas 14 December 2006 (has links) (PDF)
During cell division, chromosome segregation takes place on bipolar, microtubulebased spindles. Here, C. elegans is used to analyze spindle organization under both mitotic and meiotic conditions. First, the role of SAS-4 in organizing centrosome structure was analyzed. Partial depletion of SAS-4 in early embryos results in structurally defective centrioles. The study of this protein sheds light on the poorly understood role of the centrioles in dictating centrosome size. Second, the ultrastructure of wild-type mitotic spindle components was analyzed by electron tomography. This 3-D analysis reveals morphologically distinct microtubule end morphologies in the mitotic spindle pole. These results have structural implications for models of microtubule interactions with centrosomes Third, spindle assembly was studied in female meiosis. Specifically, the role of the microtubule severing complex katanin in spindle organization was analyzed. Electron tomography reveals fragmentation of spindle microtubules and suggests a novel katanin-dependent mechanism of meiotic spindle assembly. In this model, relatively long microtubules seen near the meiotic chromatin are converted into numerous short fragments, thus increasing the total number of polymers in an acentrosomal environment. Taken together, these results provide novel insights into the three-dimensional organization of microtubules during spindle assembly. / Die Segregation der Chromosomen während der Zellteilung wird duch bipolare, von Microtubuli-aufgebauten Spindlen gewährleistet. In der vorliegenden Arbeit wird C. elegans zur Analyse der Spindelorganisation unter mitotischen und meiotischen Bedingungen herangezogen. Erstens wird die Rolle von SAS-4 in der Organisation von Zentrosomen untersucht. Die partielle Depletierung von SAS-4 in frühen Embryonen führt zu strukturell defekten Zentriolen und wirft somit Licht auf die wenig verstandene Rolle der Zentriolen in der Bestimmung der Zentrosomengröße. Zweitens wird die Ultrastruktur der mitotischen Spindelkomponenten im Wildtyp durch Elektronentomographie untersucht. Diese 3-D-Analyse zeigt, dass im mitotischen Spindlepol unterschiedliche Morphologien der Mikrotubulienden zu finden sind. Diese Ergebnisse haben strukturelle Implikationen für Modelle der Mikrotubuli-Zentrosomen-Interaktionen. Drittens wird der Aufbau der Spindel in der weiblichen Meiose, speziell die Rolle des Mikrotubuli-schneidenden Kataninkomplexes in der Spindelorganisation, untersucht. Die Elektronentomographie zeigt hier eine Fragmentierung der Spindelmikrotubuli. Basierend auf diesem Ergebnis wird ein neues Katanin-abhängiges Modell der Formierung der Meiosespindel entwickelt, in dem relativ lange Microtubuli in Nähe des meiotischen Chromatins in zahlreiche kurze Mikrotubuli “zerschnitten” werden. Dies erhöht die Anzahl der verfügbaren Polymere in dieser azentrosomalen Situation. Zusammenfassend bringen diese Ergebnisse neue Einsichten in die räumliche Organisation der Mikrotubuli während des Spindelaufbaus.
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Road Surface Preview Estimation Using a Monocular CameraEkström, Marcus January 2018 (has links)
Recently, sensors such as radars and cameras have been widely used in automotives, especially in Advanced Driver-Assistance Systems (ADAS), to collect information about the vehicle's surroundings. Stereo cameras are very popular as they could be used passively to construct a 3D representation of the scene in front of the car. This allowed the development of several ADAS algorithms that need 3D information to perform their tasks. One interesting application is Road Surface Preview (RSP) where the task is to estimate the road height along the future path of the vehicle. An active suspension control unit can then use this information to regulate the suspension, improving driving comfort, extending the durabilitiy of the vehicle and warning the driver about potential risks on the road surface. Stereo cameras have been successfully used in RSP and have demonstrated very good performance. However, the main disadvantages of stereo cameras are their high production cost and high power consumption. This limits installing several ADAS features in economy-class vehicles. A less expensive alternative are monocular cameras which have a significantly lower cost and power consumption. Therefore, this thesis investigates the possibility of solving the Road Surface Preview task using a monocular camera. We try two different approaches: structure-from-motion and Convolutional Neural Networks.The proposed methods are evaluated against the stereo-based system. Experiments show that both structure-from-motion and CNNs have a good potential for solving the problem, but they are not yet reliable enough to be a complete solution to the RSP task and be used in an active suspension control unit.
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Spindle organization in three dimensionsMüller-Reichert, Thomas 12 December 2006 (has links)
During cell division, chromosome segregation takes place on bipolar, microtubulebased spindles. Here, C. elegans is used to analyze spindle organization under both mitotic and meiotic conditions. First, the role of SAS-4 in organizing centrosome structure was analyzed. Partial depletion of SAS-4 in early embryos results in structurally defective centrioles. The study of this protein sheds light on the poorly understood role of the centrioles in dictating centrosome size. Second, the ultrastructure of wild-type mitotic spindle components was analyzed by electron tomography. This 3-D analysis reveals morphologically distinct microtubule end morphologies in the mitotic spindle pole. These results have structural implications for models of microtubule interactions with centrosomes Third, spindle assembly was studied in female meiosis. Specifically, the role of the microtubule severing complex katanin in spindle organization was analyzed. Electron tomography reveals fragmentation of spindle microtubules and suggests a novel katanin-dependent mechanism of meiotic spindle assembly. In this model, relatively long microtubules seen near the meiotic chromatin are converted into numerous short fragments, thus increasing the total number of polymers in an acentrosomal environment. Taken together, these results provide novel insights into the three-dimensional organization of microtubules during spindle assembly. / Die Segregation der Chromosomen während der Zellteilung wird duch bipolare, von Microtubuli-aufgebauten Spindlen gewährleistet. In der vorliegenden Arbeit wird C. elegans zur Analyse der Spindelorganisation unter mitotischen und meiotischen Bedingungen herangezogen. Erstens wird die Rolle von SAS-4 in der Organisation von Zentrosomen untersucht. Die partielle Depletierung von SAS-4 in frühen Embryonen führt zu strukturell defekten Zentriolen und wirft somit Licht auf die wenig verstandene Rolle der Zentriolen in der Bestimmung der Zentrosomengröße. Zweitens wird die Ultrastruktur der mitotischen Spindelkomponenten im Wildtyp durch Elektronentomographie untersucht. Diese 3-D-Analyse zeigt, dass im mitotischen Spindlepol unterschiedliche Morphologien der Mikrotubulienden zu finden sind. Diese Ergebnisse haben strukturelle Implikationen für Modelle der Mikrotubuli-Zentrosomen-Interaktionen. Drittens wird der Aufbau der Spindel in der weiblichen Meiose, speziell die Rolle des Mikrotubuli-schneidenden Kataninkomplexes in der Spindelorganisation, untersucht. Die Elektronentomographie zeigt hier eine Fragmentierung der Spindelmikrotubuli. Basierend auf diesem Ergebnis wird ein neues Katanin-abhängiges Modell der Formierung der Meiosespindel entwickelt, in dem relativ lange Microtubuli in Nähe des meiotischen Chromatins in zahlreiche kurze Mikrotubuli “zerschnitten” werden. Dies erhöht die Anzahl der verfügbaren Polymere in dieser azentrosomalen Situation. Zusammenfassend bringen diese Ergebnisse neue Einsichten in die räumliche Organisation der Mikrotubuli während des Spindelaufbaus.
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Über den neurenterischen Kanal im Embryo des Menschen und des Neuweltaffen Callithrix jacchus / About the Neurenteric Canal in the Human embryo and the embryo of the new-world-monkey Callithrix jacchusNachtigal, Alexander 31 December 1100 (has links)
No description available.
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Building a Wiki resource on digital 3D reconstruction related knowledge assetsMünster, Sandra, Niebling, Florian 15 May 2019 (has links)
Purpose – While single theoretical approaches related to visual humanities research and in particular digital 3D reconstruction – as the virtual, interpretative 3D modeling and visualization of historical objects – are widely described in compendia like Wikipedia, and various publications discuss approaches from certain disciplinary perspectives, a comprehensive and multidisciplinary systematization is still missing. Against this background, the research activity described within this article is intended to gain a wide and multidisciplinary overview for research approaches, theories, and methods which are relevant to investigate or explain knowledge-related phenomena in the context of visual humanities research and education.
Design/methodology/approach – To meet these interests we intend to set up a Wiki resource as a structured repository. The content will be based on (a) interactive workshops held at conferences to collect and structure knowledge assets on visual knowledge involving experts from different domains. Moreover, (b) a student seminar starting in early 2017 is designated to describe some typical research designs as well as amend related methods and theories in the Wiki resource based on Wikipedia articles. A content structuring principle for the Wiki resource follows the guidelines of Wikimedia as well as plans for the results to be populated again in Wikipedia.
Originality/value – While Wiki approaches are frequently used in the context of visual humanities, these resources are primarily created by experts. Furthermore, Wiki-based approaches related to visualization are often focused on a certain disciplinary context as, for example, art history. A unique aspect of the described setting is to build a Wiki on digital 3D reconstruction including expertise from different knowledge domains – i.e. on perception and cognition, didactics, information sciences, as well as computing and visual humanities. Moreover, the combination of student work and assessments by experts also provides novel insights for educational research.
Practical implications – The intended product is a comprehensive and multidisciplinary structured repository on digital 3D reconstruction research approaches, methods, theories, publication bodies, and good practice examples. The editing of the project results into the Wikipedia will lead to a wide dissemination and visibility of group activities and outcomes as well as enhance competencies of all contributors on collaborative work.
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