Dissertations / Theses on the topic '3D model database'

Nella tesi verrà mostrata la realizzazione di un applicativo dotato di funzionalità di Realtà Aumentata attraverso Unity 3D. Inizialmente verrà fornita una panoramica sulla Augmented Reality e come viene utilizzata oggi, verranno descritti gli strumenti utilizzati e le scelte implementative più importanti. L'applicazione realizzata permette di istanziare oggetti nello spazio circostante e recuperare i modelli tridimensionali da un Realtime Database (Firebase). L'app è stata sviluppata per sistemi Android.

The primary object of the master thesis is creating escape route analysis in 3D model of a building. Analysis is created using mainly open source tools like PostgreSQL with PostGIS and pgRouting extensions.

The Thornton Well Field, located in an area of dominantly (~80%) agricultural land-use, produces ~50% of the drinking water for the city of Woodstock. Since the mid 1990?s nitrate concentrations in some of the supply wells are above the Maximum Allowable Concentration (MAC) of 10mg-N/L. The source of the nitrate is believed to be from agricultural fertilizing practices. As response to this problem, the County of Oxford purchased 111 hectares of farmland within the capture zone of the Thornton Well Field. This land is rented back to farmers with restrictions placed on the amount of nitrate fertilizer that can be applied in an attempt to sustainably reduce the nitrate concentrations in the ThorntonWell Field below MAC.

The objective of this thesis is to improve the site conceptual hydrogeologic model, both at a spatial scale suitable for numerical analysis through regional groundwater flow modelling (representative distance ~9km) and at a smaller scale (representative distance ~2km) for nitrate transport modelling in the vicinity of the Thornton Well Field and the purchased land. Field investigations aimed to support the site hydrogeologic model involved drilling, geologic logging, and instrumentation of a 72m deep borehole completed to bedrock in the center of the nitrate plume, at the border of the farmland under consideration. The shallow subsurface features encountered during this initial drilling operation were tracked below the farm fields with geophysical tools and additional drilling and core logging throughout the field site. Transient hydraulic head observations in combination with on-site precipitation measurements were used to indicate where a hydraulic connection between ground surface and deeper layers exists, which allow rapid infiltration to occur into a glaciofluvial outwash channel which was identified as one important pathway for nitrate transport to the Thornton Well Field. One receptor at the end of that pathway, the screen of the supply Well 01, was depth-discrete profiled for water inflow and nitrate concentrations to obtain better characteristics of the receptor.

A method was developed to estimate the nitrate mass stored in the unsaturated zone below Parcel B, permitting an estimation of the time frame required for flushing the nitrate out of this zone, and the anticipated effects on nitrate concentrations in the supply wells. The spatial distribution of nitrate concentrations in the unsaturated zone and in the aquifer units was analyzed. It was found that the nitrate concentration within the unsaturated zone below Parcel B is ~16mg-N/L, resulting in a total nitrogen mass of ~20t within that zone. It was shown that significant reductions (~10%) in nitrate concentrations in the supply wells of the Thornton Well Field can be achieved, assuming zero nitrate mass influx into the domain from Parcel B.

A comprehensive data base was developed to organize, manage, and analyze all site measured data for that purpose, and regional hydrogeologic data from the MOE Water Well Record Database. The contents of this database in conjunction with the MOE Water Well Record Database were used to construct a three-dimensional digital representation of the hydrostratigraphic units at a regional and at a local scale. This three-dimensional hydrostratigraphic unit spatial distribution along with surface watershed information and potentiometric surfaces of the various aquifer units will be used to define a suitable spatial domain and associated boundary conditions for future modelling efforts. This hydrostratigraphic model will serve as basis for predicting the effects of agricultural land-use changes within the capture zone of the Thornton Well Field (Parcel B) on the nitrate concentrations in the supply wells of the Thornton Well Field.

This Ph.D. thesis tackles the issue of sill and video object categorization. The objective is to associate semantic labels to 2D objects present in natural images/videos. The principle of the proposed approach consists of exploiting categorized 3D model repositories in order to identify unknown 2D objects based on 2D/3D matching techniques. We propose here an object recognition framework, designed to work for real time applications. The similarity between classified 3D models and unknown 2D content is evaluated with the help of the 2D/3D description. A voting procedure is further employed in order to determine the most probable categories of the 2D object. A representative viewing angle selection strategy and a new contour based descriptor (so-called AH), are proposed. The experimental evaluation proved that, by employing the intelligent selection of views, the number of projections can be decreased significantly (up to 5 times) while obtaining similar performance. The results have also shown the superiority of AH with respect to other state of the art descriptors. An objective evaluation of the intra and inter class variability of the 3D model repositories involved in this work is also proposed, together with a comparative study of the retained indexing approaches . An interactive, scribble-based segmentation approach is also introduced. The proposed method is specifically designed to overcome compression artefacts such as those introduced by JPEG compression. We finally present an indexing/retrieval/classification Web platform, so-called Diana, which integrates the various methodologies employed in this thesis

Cette thèse porte sur la catégorisation d'objets vidéo. L'objectif est d'associer des étiquettes sémantiques à des objets 2D présents dans les images/vidéos. L'approche proposée consiste à exploiter des bases d'objets 3D classifiés afin d'identifier des objets 2D inconnus. Nous proposons un schéma de reconnaissance d'objet, conçu pour fonctionner pour des applications en temps réel. La similitude entre des modèles 3D et des contenus 2D inconnu est évaluée à l'aide de la description 2D/3D. Une procédure de vote est ensuite utilisée afin de déterminer les catégories les plus probables de l'objet 2D. Nous proposons aussi une stratégie pour la sélection des vues les plus représentatives d'un objet 3D et un nouveau descripteur de contour (nommé AH). L'évaluation expérimentale a montré que, en employant la sélection intelligente de vues, le nombre de projections peut être diminué de manière significative (jusqu'à 5 fois) tout en obtenant des performances similaires. Les résultats ont également montré la supériorité de l'AH par rapport aux autres descripteurs adoptés. Une évaluation objective de la variabilité intra et inter classe des bases de données 3D impliqués dans ce travail est également proposé, ainsi qu'une étude comparative des approches d'indexations retenues. Une approche de segmentation interactive est également introduite. La méthode proposée est spécifiquement conçu pour surmonter les artefacts de compression tels que ceux mis en place par la compression JPEG. Enfin, nous présentons une plate-forme Web pour l'indexation/la recherche/la classification, qui intègre les différentes méthodologies utilisées dans cette thèse
This Ph.D. thesis tackles the issue of sill and video object categorization. The objective is to associate semantic labels to 2D objects present in natural images/videos. The principle of the proposed approach consists of exploiting categorized 3D model repositories in order to identify unknown 2D objects based on 2D/3D matching techniques. We propose here an object recognition framework, designed to work for real time applications. The similarity between classified 3D models and unknown 2D content is evaluated with the help of the 2D/3D description. A voting procedure is further employed in order to determine the most probable categories of the 2D object. A representative viewing angle selection strategy and a new contour based descriptor (so-called AH), are proposed. The experimental evaluation proved that, by employing the intelligent selection of views, the number of projections can be decreased significantly (up to 5 times) while obtaining similar performance. The results have also shown the superiority of AH with respect to other state of the art descriptors. An objective evaluation of the intra and inter class variability of the 3D model repositories involved in this work is also proposed, together with a comparative study of the retained indexing approaches . An interactive, scribble-based segmentation approach is also introduced. The proposed method is specifically designed to overcome compression artefacts such as those introduced by JPEG compression. We finally present an indexing/retrieval/classification Web platform, so-called Diana, which integrates the various methodologies employed in this thesis

Digital tools have been increasingly used, in the last decades, for the study and representation of the city history. As the available instruments develop and the researchersb ecome more familiar with them, their use turns out to be more effective and provides richer results. This study aims to explore the use of information technology, particularly 3D models, for the city history research. When this study was elaborated, few initiatives effectivelly applied those new tools to convey the history of the city. A smaller number of published scientific enterprises investigated that operation. Therefore, the study is structured mainly on the analysis of some precedents based on those tools, together with others selected for applying creatively traditional methods. These analyses also raise questionings on related issues such as historical narratives, traditional methods of historical graphic representation or other digital representation modes. The examination of those subjects constitutes the thesis' theoretical part. The conclusion is presented in the form of a digital alternative for the representation of the city history. The tool developed as a prototype is grounded on 3D models representing different periods of the city linked to a database of a great diversity of historical documents. Thus, the city history is accessed through images of the significant sites from the 3D models. The prototype development is based on the assumptions that this process of retrieving historical information related to city spaces facilitates the understanding of the past culture. Furthermore, when the readers associate the space they know in the city to the historical information, they understand better the past culture that shaped it, strengthen their identity and intensify the relationship to the place they dwell in.

Fractures and fracture networks govern the mechanical and fluid flow behavior of rock masses. Tunneling and other rock mechanics applications therefore require the characterization of rock fractures based on geological data. Field investigations produce only a limited amount of data from boreholes, outcrops, cut slopes, and geophysical surveys. In tunneling, the process of excavation creates a priceless opportunity to gather more data during construction. Typically, however, these data are not utilized due to the impedance of sampling and analysis on the flow of construction, and safety concerns with sampling within unlined tunnel sections. However, the use of this additional data would increase the overall safety, quality, and cost savings of tunneling. This study deals with several aspects of the above, with the goal of creating methods and tools to allow engineers and geologists to gather and analysis fracture data in tunnels without interrupting the excavation and without compromising safety. Distribution-independent trace density and mean trace length estimators are developed using principles of stereology. An optimization technique is developed utilizing Differential Evolution to infer fracture size and shape from trace data obtained on two or more nonparallel sampling planes. A method of producing nearly bias free empirical trace length CDF's is also introduced. These new methods and tools were validated using Monte Carlo simulations. A field study was conducted in an existing tunnel allowing the above methods and tools to be further validated and tested. A relational database was developed to aid in storage, retrieval, and analysis of field data. Fracture models were built and updated using fracture data from within the tunnel. Utilization of state of the art imaging techniques allowed for remote sampling and analysis, which were enhanced by the use of 3d visualization techniques.
Ph. D.

The review object is the subsystem verification and printing 3D-model online learning system mixed type. To do this, a review of analogues, technologies, stages of printing were identified. The aim is to design with IP topics that uses the additive technologies in the educational process. In the given IDEF – diagram describing the function of the system; authentication rules, verification of 3D-models, sending the model to print, selecting a device online, and basic screen forms.

隨著互聯網上3D模型的大量增加，產生了開發3D模型搜索引擎的需求。本論文提出了一個基於草圖和3D模型的3D模型搜索引擎。
對於使用3D模型作檢索條件的搜索系統，我們提出了兩種新的3D模型描述子，分別叫做Sphere Image 描述子和Bag-of-View-Words (BoVW)描述子。Sphere Image描述子是由一系列投影圖的特徵組成。我們將每一個視角看到的圖形都當作是一個"像素"，把視角的位置看作像素點的位置，把所看到的圖形的特徵值看作是像素值。我們同時也提出了一種基於概率圖的3D模型匹配算法，並開發了一個3D模型檢索系統來檢測我們的算法。BoVW描述子通過3D模型投影圖出現的次數來描述3D模型。我們用一種自適應的聚類算法，對3D模型的所有投影圖進行分類，然後用一個多層次的柱狀圖來描述一個3D模型。我們同時提出一種新的金字塔匹配算法來比較3D模型。我們使用SHREC和普林斯頓的3D模型庫來檢驗我們的系統，實驗結果證明我們的系統在檢索效率和精度上都優與現今的3D模型檢索系統。
對於使用草圖作檢索條件的3D模型搜索系統，我們提出Bigger ExposureOpportunity Views (BEOV) 描述子來表示3D模型，同時提出Shape-Ring描述子來表示草圖。BEOV描述子是由一些特徵圖組成，這些圖的特點是更容易被人們看到。Shape-Ring描述子保留了圖形的輪廓和內部特徵。我們使用SHREC2012草圖數據庫來檢驗我們的系統，實驗結果證明我們的系統在精度和計算複雜度上都優與現今的3D模型檢索系統。
The large number of 3D models on the Internet encourages us to develop 3D model search engines. In this dissertation, we present a 3D model retrieval system using both the 3D model query and the sketch query.
For 3D model query based retrieval system, we propose two new 3D model descriptors, named the Sphere Image and the Bag-of-View-Words (BoVW) descriptor. The Sphere Image is defined as a collection of view features. A viewpoint of a 3D model is regarded as a "pixel": (1) The position of the viewpoint is denoted as the coordinate of the "pixel". (2) The feature descriptor of the projected view is denoted as the value of the "pixel". We also propose a probabilistic graphical model for 3D model matching, and develop a 3D model retrieval system to test our approach. The BoVW descriptor describes a 3D model by measuring the occurrences of its projected views. An adaptive clustering method is applied to reduce the redundancy of the projected views of each 3D model. A 3D model is represented by a multi-resolution histogram, which is combined by several BoVW descriptors at different levels. The codebook is obtained by unsupervised learning. We also propose a new pyramid matching method for 3D model comparison. We have conducted experiments based on the SHape REtrieval Contest (SHREC) 2012 Generic 3D model benchmark and the Princeton Shape Benchmark (PSB). Experimental results indicate that our system outperforms some state-of-the-art 3D model retrieval systems with respect to the retrieval precision and the computational cost.
For sketch query based retrieval system, we propose a Bigger Exposure Opportunity Views (BEOV) descriptor and a Shape-Ring descriptor, for representing the 3D model candidates and the sketch query, respectively. The BEOV descriptor represents a 3D model by several characteristic views, which have more chances to be exposed to people. The Shape-Ring descriptor preserves the features of the contour and the inside detail of the sketch query and the BEOV. Experiments have been conducted based on the SHape REtrieval Contest (SHREC) 2012 and SHREC 2013 sketch track data sets. Our approach outperforms the existing 3D model retrieval methods in terms of the retrieval precision and the computational cost.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Ding, Ke.
Thesis (Ph.D.) Chinese University of Hong Kong, 2014.
Includes bibliographical references (leaves 107-120).
Abstracts also in Chinese.

碩士
國立臺灣科技大學
營建工程系
97
In recent year, positional sensing technology has been applied in construction for real-time monitoring of elements, such as materials, equipments, and personals, in a construction site. However, the presentation of sensing data in most real-time monitoring systems is in the form of texts and numbers in table or map. In this way, it would be somewhat difficult to realize the corresponding situation and layout visually in site. This study proposed a mode to generate 3-dimensional (3D) model of a developing site based on real-time positioning data. A construction model component database is adopted to achieve efficiency in generating site model in the proposed mode. The model component database has pre-stored the models of all basic elements that could possibly exist in a construction site. On the other hand, a positional sensing database is established for accumulating positioning data of monitored elements collected by sensing units in site. By integrating these two databases, the generation of a 3D model automatically for simulating current layout of a construction site can be achieved. The proposed model can allow manager to intuitively track the progress of a construction as well as the real-time movements of all the monitored elements in site.

碩士
國立交通大學
多媒體工程研究所
102
Existing methods can barely get satisfactory results since they usually assume the objects are rigid. Therefore we present a novel approach that we can retrieve articulate 3D models from database. In this paper, we propose a novel method to retrieve models by using both global and local information. The global information is the original 2D views (projected views of a 3D model or frames of a depth camera). Since the articulate 3D models may have various pose (various orientations and diverse motions of body parts or limbs), we still need local information. The local information is the local shapes of the 2D views. Take a human image for example, the hands, lags, and the body are the local information of the this image. By using the local information, the recognition rate is increasing, because we can retrieve much more models with different pose. Meanwhile, we also define a feature set which is robust against various pose and noise. By using our feature set, we can deal with some special case such as 4-lags animal models. The advantage of our method is that we do not need a well-aligned model pose. Best of all, since the cost average of the cost time of each inputs is under 1 seconds, the online retrieve system is almost real-time.

Yes
Aims: To create a gait database with optimum accuracy of joint rotational data and an accu-rate representation of 3D volume, and explore the potential of using the database in studying the relationship between static and dynamic features of a human’s gait. Study Design: The study collected gait samples from 38 subjects, in which they were asked to walk, run, walk to run transition, and walk with a bag. The motion capture, video, and 3d measurement data extracted was used to analyse and build a correlation between features. Place and Duration of Study: The study was conducted in the University of Bradford. With the ethical approval from the University, 38 subjects’ motion and body volumes were recorded at the motion capture studio from May 2011- February 2013. Methodology: To date, the database includes 38 subjects (5 females, 33 males) conducting walk cycles with speed and load as covariants. A correlation analysis was conducted to ex-plore the potential of using the database to study the relationship between static and dynamic features. The volumes and surface area of body segments were used as static features. Phased-weighted magnitudes extracted through a Fourier transform of the rotation temporal data of the joints from the motion capture were used as dynamic features. The Pearson correlation coefficient is used to evaluate the relationship between the two sets of data. Results: A new database was created with 38 subjects conducting four forms of gait (walk, run, walk to run, and walking with a hand bag). Each subject recording included a total of 8 samples of each form of gait, and a 3D point cloud (representing the 3D volume of the subject). Using a Pvalue (P<.05) as a criterion for statistical significance, 386 pairs of features displayed a strong relationship. Conclusion: A novel database available to the scientific community has been created. The database can be used as an ideal benchmark to apply gait recognition techniques, and based on the correlation analysis, can offer a detailed perspective of the dynamics of gait and its relationship to volume. Further research in the relationship between static and dynamic features can contribute to the field of biomechanical analysis, use of biometrics in forensic applications, and 3D virtual walk simulation.

Automated human face recognition is a computer vision problem of considerable practical significance. Existing two dimensional (2D) face recognition techniques perform poorly for faces with uncontrolled poses, lighting and facial expressions. Face recognition technology based on three dimensional (3D) facial models is now emerging. Geometric facial models can be easily corrected for pose variations. They are illumination invariant, and provide structural information about the facial surface. Algorithms for 3D face recognition exist, however the area is far from being a matured technology. In this dissertation we address a number of open questions in the area of 3D human face recognition. Firstly, we make available to qualified researchers in the field, at no cost, a large Texas 3D Face Recognition Database, which was acquired as a part of this research work. This database contains 1149 2D and 3D images of 118 subjects. We also provide 25 manually located facial fiducial points on each face in this database. Our next contribution is the development of a completely automatic novel 3D face recognition algorithm, which employs discriminatory anthropometric distances between carefully selected local facial features. This algorithm neither uses general purpose pattern recognition approaches, nor does it directly extend 2D face recognition techniques to the 3D domain. Instead, it is based on an understanding of the structurally diverse characteristics of human faces, which we isolate from the scientific discipline of facial anthropometry. We demonstrate the effectiveness and superior performance of the proposed algorithm, relative to existing benchmark 3D face recognition algorithms. A related contribution is the development of highly accurate and reliable 2D+3D algorithms for automatically detecting 10 anthropometric facial fiducial points. While developing these algorithms, we identify unique structural/textural properties associated with the facial fiducial points. Furthermore, unlike previous algorithms for detecting facial fiducial points, we systematically evaluate our algorithms against manually located facial fiducial points on a large database of images. Our third contribution is the development of an effective algorithm for computing the structural dissimilarity of 3D facial surfaces, which uses a recently developed image similarity index called the complex-wavelet structural similarity index. This algorithm is unique in that unlike existing approaches, it does not require that the facial surfaces be finely registered before they are compared. Furthermore, it is nearly an order of magnitude more accurate than existing facial surface matching based approaches. Finally, we propose a simple method to combine the two new 3D face recognition algorithms that we developed, resulting in a 3D face recognition algorithm that is competitive with the existing state-of-the-art algorithms.
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Record keeping and management of electrical utilities inside buildings is an important aspect to ensure effective electrical distribution. The ability to find the location of each electrical feature inside a building and extract information about it helps to solve network problems faster. The use of a spatial database structure facilitates the maintenance and general operations of an electrical network across different buildings. The aim of this study is to design and develop a 3D data model to provide a management system for electrical utilities inside buildings. The geodatabase provides integrated information between different electrical components forming the network inside the specified buildings in the study area. A prototype called the PUK geodatabase was designed and developed for the NWU Potchefstroom Campus as a 3D data model. The data model consists of raster and vector data used in network datasets, relationship classes and topology rules. The aim of this project was accomplished through the 3D analysis capabilities of the model. The research determined that the prototype called the PUK geodatabase can be utilized as a 3D management system for electrical utilities across the different floor levels of a building.
Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2012