Model-based metrics for assessing completeness and accuracy for 3D image-based reconstruction methods

Structure from Motion (SfM) is a technique for inferring the underlying 3D geometry of the real world from a set of unordered images using a pinhole camera model. Due to a wider availability of cameras, the availability of commodity smart phones and tablets equipped with cameras, and enhanced computational power, more attention is now being given to leverage visual data such as still images and video streams for the automated processes such as mobile augmented reality and engineering performance monitoring applications. Discuss significant research progress related to leveraging rich visual data for 3D image-based point butt modeling purposes, today there is no way to provide feedback to users who are taken these imagery on the best location and viewpoints for cameras. To address current limitations, this thesis introduces 3D image-based modeling incrementation -- a variant of incremental SfM -- where no prior knowledge of the new image/cameras is given. The state-of-the-art online algorithm for SfM only focus on processing video streams in which the images are ordered and sequence is known as a priori. In this thesis, we use a heuristic approach to avoid the need for pair-wise image matching which is a bottleneck for incremental SfM processes. We also discuss how we measure the completeness of the 3D point butt without the knowledge of the ground truth. We propose a general framework for feedback systems where the location and the pose of the new camera that can enhance the completeness of the 3D image-based point butt is predicted. We demonstrate that this framework can assist users of SfM methods to automatically improve the completeness of the reconstructed 3D point butt models form the real world scenery. We validate our algorithm on both small and large dataset as well as indoor and outdoor scenes using daily photologs collected from two ongoing construction sites. The perceived benefits and practical significance of the proposed method are also discussed in detail

OMap: An assistive solution for identifying and localizing objects in a semi-structured environment

A system capable of detection and localization of objects of interest in a semi-structured environment will enhance the quality of life of people who are blind or visually impaired. Towards building such a system, this thesis presents a personalized real-time system called O\u27Map that finds misplaced/moved personal items and localizes them with respect to known landmarks. First, we adopted a participatory design approach to identify users’ need and functionalities of the system. Second, we used the concept from system thinking and design thinking to develop a real-time object recognition engine that was optimized to run on low form factor devices. The object recognition engine finds robust correspondences between the query image and item templates using K-D tree of invariant feature descriptor with two nearest neighbors and ratio test. Quantitative evaluation demonstrates that O\u27Map identifies object of interest with an average F-measure of 0.9650

Photogrammetry as a surveying thechnique apllied to heritage constructions recording - avantages and limitations

Dissertação de Mestrado Integrado em Arquitetura, com a especialização em Arquitetura apresentada na Faculdade de Arquitetura da Universidade de Lisboa para obtenção do grau de Mestre.A presente dissertação tem por objectivo investigar e evidenciar as vantagens da aplicação da fotogrametria, e possíveis integrações com outros métodos de levantamento, como seja o varrimento laser terrestre, posicionamento por GPS, entre outros, para realizar levantamentos de construções patrimoniais ou eruditas e a respectiva produção de documentação base para viabilizar intervenções de conservação, restauro ou reabilitação. A motivação para a investigação advém da aplicação flexível, versátil, simples, acessível, e baixo-custo da fotogrametria em projectos de levantamento pequenos ou extensos. Tenciona-se igualmente colmatar as desvantagens tradicionais da fotogrametria, nomeadamente a transição entre espaços interiores e exteriores, e registo de espaços estreitos, de difícil acesso, e de geometrias complexas, num único projecto de documentação. Pretende-se ultrapassar estas dificuldades através da utilização máxima das potencialidades da fotogrametria com o uso de imagens olho de peixe e apenas como último recurso utilizar instrumentos complementares. No caso de estudo principal, o Castelo do Convento de Cristo, demonstra-se a aplicação dos métodos investigados. Nos casos de estudo secundários abordam-se problemas parcelares, desde elementos decorativos até à totalidade do edificado: Convento dos Capuchos, em Sintra; Alcáçova e trecho de muralha do Castelo de Sesimbra; Igreja de Stº André, em Mafra; entre outros. Os casos auxiliaram na determinação de procedimentos a generalizar posteriormente. Por fim, propõem-se algoritmos que auxiliam na produção de documentação.ABSTRACT: The present dissertation aims to research and demonstrate the advantages of the application of photogrammetry, and its possible integrations with other methods, such as terrestrial laser scanning, GPS positioning, and among others, to perform surveys of heritage or erudite buildings and respective production of base documentation to enable interventions of conservation, restoration, or rehabilitation. The motivation for researching is due to the flexible, versatile, simple, affordable, and low-cost application of photogrammetry in small and extensive survey projects. It is also intended to overcome the traditional disadvantages of photogrammetry, such as the transition between interior and exterior spaces, and difficulty of recording narrow, hard-to-access, and complex geometric spaces, in a single project. It is intended to overcome such challenges by maximizing the potential uses of photogrammetry with the use of fisheye images and by using other survey instruments as a last resort. In the main case study, the Castle of the Convent of Christ, the application of the investigated methods is demonstrated. In the secondary case studies, partial problems are addressed, ranging from decorative elements to the entire building: Convento dos Capuchos, in Sintra; Citadel and section of a wall of the Castle of Sesimbra; Igreja de St André, in Mafra; among others; The case studies aided in determining general procedures. Finally, algorithms that accelerate the production of documentation are proposed.N/

A Survey of Computer Vision Methods for 2D Object Detection from Unmanned Aerial Vehicles

The spread of Unmanned Aerial Vehicles (UAVs) in the last decade revolutionized many applications fields. Most investigated research topics focus on increasing autonomy during operational campaigns, environmental monitoring, surveillance, maps, and labeling. To achieve such complex goals, a high-level module is exploited to build semantic knowledge leveraging the outputs of the low-level module that takes data acquired from multiple sensors and extracts information concerning what is sensed. All in all, the detection of the objects is undoubtedly the most important low-level task, and the most employed sensors to accomplish it are by far RGB cameras due to costs, dimensions, and the wide literature on RGB-based object detection. This survey presents recent advancements in 2D object detection for the case of UAVs, focusing on the differences, strategies, and trade-offs between the generic problem of object detection, and the adaptation of such solutions for operations of the UAV. Moreover, a new taxonomy that considers different heights intervals and driven by the methodological approaches introduced by the works in the state of the art instead of hardware, physical and/or technological constraints is proposed

Monen näkymän stereon rekonstruktio tietokonegrafiikan sisällön taltiointiin

Rendering of photorealistic models is becoming increasingly feasible and important in computer graphics. Due to the high amount of work in creating such models by hand, required by the need of high level of detail in geometry, colors, and animation, it is desirable to automate the model creation. This task is realised by recovering content from photographs that describe the modeled subject from multiple viewpoints. In this thesis, elementary theory on image acquisition and photograph-based reconstruction of geometry and colors is studied and recent research and software for graphics content reconstruction are reviewed. Based on the studied background, a rig is built as a grid of nine off-the-shelf digital cameras, a custom remote shutter trigger, and supporting software. The purpose of the rig is to capture high-quality photographs and video in a reliable and practical manner, to be processed in multi-view reconstruction programs. The camera rig was configured to shoot small static subjects for experiments. The resulting photos and video were then processed directly for the subject's geometry and color, with little or no image enhancements done. Two typical reconstruction software pipelines were described and tested. The rig was found to perform well for several subjects with little subject-specific tuning; issues in the setup were analyzed and further improvements suggested based on the captured test models. Image quality of the cameras was found to be excellent for the task, and most problems arose from uneven lighting and practical issues. The developed rig was found to produce sub-millimeter scale accuracy in geometry and texture of subjects such as human faces. Future work was suggested for lighting, video synchronization and study of state-of-the-art image processing and reconstruction algorithms.Fotorealististen mallien renderöinti on yhä tärkeämpää ja mahdollisempaa tietokonegrafiikassa. Näiden mallien luominen käsityönä on työlästä vaaditun korkean tarkkuuden takia geometrian, värien ja animaation osalta, ja onkin haluttavaa korvata käsityö automatiikalla. Automatisointi voidaan suorittaa taltioimalla sisältö valokuvista, jotka kuvastavat samaa kohdetta useammasta näkymästä. Tässä diplomityössä tarkastellaan kuvantamista ja valokuvapohjaisen geometrian rekonstruktiota geometrian ja värien kannalta ja katsastetaan viimeaikainen tutkimus ja ohjelmistot grafiikkasisällön rekonstruointiin. Taustan pohjalta rakennetaan laitteisto, joka koostuu yhdeksästä valmiina saatavilla olevasta digikamerasta aseteltuna hilaksi, itse tehdystä etälaukaisimesta sekä ohjelmistoista. Laitteiston tarkoituksena on taltioida luotettavalla ja käytännöllisellä tavalla korkealaatuisia valokuvia ja videokuvaa, joita voi käsitellä monen näkymän stereon rekonstruktion tietokonesovelluksissa. Laitteisto säädettiin kuvaamaan pieniä staattisia kohteita kokeita varten. Tuloksena saadusta kuvamateriaalista laskettiin kohteen geometria ja värit ilman mainittavaa kuvanparannuksen käyttöä. Käytiin läpi kaksi tyypillistä rekonstruktio-ohjelmistoa testiksi ja laitteiston havaittiin soveltuvan hyvin useisiin kohteisiin ilman erityistä säätämistä. Kameroiden kuvanlaatu todettiin tehtävään erinomaiseksi ja useimmat haasteet johtuivat epätasaisesta valaistuksesta ja käytännön pulmista. Laitteiston todettiin tuottavan alle millimetriskaalan geometriaa ja pintavärikuvaa ihmiskasvojen kaltaisista kohteista. Jatkotyötä ehdotettiin valaistukseen, videon synkronointiin ja viimeisimpien kuvankäsittely- ja rekonstruktioalgoritmien tutkimiseen

Image Based Indoor Navigation

Over the last years researchers proposed numerous indoor localization and navigation systems. However, solutions that use WiFi or Radio Frequency Identification require infrastructure to be deployed in the navigation area and infrastructure less techniques, e.g. the ones based on mobile cell ID or dead reckoning suffer from large accuracy errors. In this Thesis, we present a novel approach of infrastructure-less indoor navigation system based on computer vision Structure from Motion techniques. We implemented a prototype localization and navigation system which can build a navigation map using area photos as input and accurately locate a user in the map. In our client-server architecture based system, a client is a mobile application, which allows a user to locate her or his position by simply taking a photo. The server handles map creation, localization queries and path finding. After the implementation, we evaluated the localization accuracy and latency of the system by benchmarking navigation queries and the model creation algorithm. The system is capable of successfully navigating in Aalto University computer science department library. We were able to achieve an average error of 0.26 metres for successfully localised photos. In the Thesis, we also present challenges that we solved to adapt computer vision techniques for localisation purposes. Finally we observe the possible future work topics to adapt the system to a wide use

Human pose estimation from video and inertial sensors

[no abstract

China Brand Homes: Business history and projects¿ analysis of China Vanke Co. Ltd., 1988-2016

L'abstract è presente nell'allegato / the abstract is in the attachmen

Urban Ecosystem Services and Tourism

Urban tourism depends on the place specific qualities of destinations. In many cities, climate change poses a threat to these qualities, through increasing risk of excessive heat, draught and flooding. Cities need to adapt to reduce these risks. One way of doing this is to improve their green infrastructure. Urban forests, parks, rivers and wetlands may help reduce the effects of climate change in cities. At the same time, green infrastructure provide a variety of ecosystem services to the community. In particular, cultural ecosystem services such as recreation, andesthetical values take place in urban green infrastructure; they provide value in the form of improved experiences. These mainly benefit the locals but they may also be important for tourism. Such relations between ecosystem services and tourism have in earlier literature been recognized in rural contexts but very seldom in urban. This paper reports preliminary findings from qualitative case studies in the South of Sweden and Berlin, Germany. They focus on how urban planning projects (primarily aimed at mitigating GHG emissions and adapting to climatechange) can be extended to develop places where experience values for both residents and visitors are created alongside other kinds of ecosystem services. We suggest that the need for climate change adaptation in a city may be used as a means to improve its place specific qualities as a tourist destination. By developing green infrastructure in innovative and environmentally friendly ways, the quality of ecosystem services improves, including those relevant for both visitors and residents. Protecting and building green infrastructure, therebyenhancing a city´s visible qualities and its reputation as a sustainable destination, may also be valuable in marketing the city