Design and implementation of a relative localization system for ground and aerial robotic teams

The main focus of this thesis is to address the relative localization problem of a heterogenous team which comprises of both ground and micro aerial vehicle robots. This team configuration allows to combine the advantages of increased accessibility and better perspective provided by aerial robots with the higher computational and sensory resources provided by the ground agents, to realize a cooperative multi robotic system suitable for hostile autonomous missions. However, in such a scenario, the strict constraints in flight time, sensor pay load, and computational capability of micro aerial vehicles limits the practical applicability of popular map-based localization schemes for GPS denied navigation. Therefore, the resource limited aerial platforms of this team demand simpler localization means for autonomous navigation. Relative localization is the process of estimating the formation of a robot team using the acquired inter-robot relative measurements. This allows the team members to know their relative formation even without a global localization reference, such as GPS or a map. Thus a typical robot team would benefit from a relative localization service since it would allow the team to implement formation control, collision avoidance, and supervisory control tasks, independent of a global localization service. More importantly, a heterogenous team such as ground robots and computationally constrained aerial vehicles would benefit from a relative localization service since it provides the crucial localization information required for autonomous operation of the weaker agents. This enables less capable robots to assume supportive roles and contribute to the more powerful robots executing the mission. Hence this study proposes a relative localization-based approach for ground and micro aerial vehicle cooperation, and develops inter-robot measurement, filtering, and distributed computing modules, necessary to realize the system. The research study results in three significant contributions. First, the work designs and validates a novel inter-robot relative measurement hardware solution which has accuracy, range, and scalability characteristics, necessary for relative localization. Second, the research work performs an analysis and design of a novel nonlinear filtering method, which allows the implementation of relative localization modules and attitude reference filters on low cost devices with optimal tuning parameters. Third, this work designs and validates a novel distributed relative localization approach, which harnesses the distributed computing capability of the team to minimize communication requirements, achieve consistent estimation, and enable efficient data correspondence within the network. The work validates the complete relative localization-based system through multiple indoor experiments and numerical simulations. The relative localization based navigation concept with its sensing, filtering, and distributed computing methods introduced in this thesis complements system limitations of a ground and micro aerial vehicle team, and also targets hostile environmental conditions. Thus the work constitutes an essential step towards realizing autonomous navigation of heterogenous teams in real world applications.

Fibrous Aerial Robotics: study of spiderweb strategies for the design of architectural envelopes using swarms of drones and inflatable formworks

La tesi approccia in modo transdisciplinare biologia, architettura e robotica, con la finalità di indagare e applicare principi costruttivi attraverso l’interazione tra sciami di droni che depositano materiale fibroso su strutture gonfiabili di supporto. L’attenzione principale è nello sviluppo (attraverso un workflow computazionale che gestisce sciami di agenti costruttori) di una tettonica che integra struttura, spazio e ornamento all’interno dello stesso processo progettuale, il quale si sviluppa coerentemente dall’ideazione fino alla fabbricazione. Sono stati studiati modelli biologici quali le colonie di ragni sociali, i quali costruiscono artefatti di grandi dimensioni relativamente a quelle del singolo individuo grazie ad un’organizzazione coordinata ed emergente e alle proprietà dei sistemi fibrosi. L’auto-organizzazione e la decentralizzazione, insieme alle caratteristiche del sistema materiale, sono stati elementi indispensabili nell’estrapolazione prima e nella codificazione poi di un insieme di regole adatte allo sviluppo del sistema costruttivo. Parallelamente alla simulazione digitale si è andati a sviluppare anche un processo fisico di fabbricazione che, pur tenendo conto dei vincoli economici e tecnici, potesse dimostrarsi una prova di concetto e fattibilità del sistema costruttivo. Sono state investigate le possibilità che un drone offre nel campo della fabbricazione architettonica mediante il rilascio di fili su elementi gonfiabili in pressione. Il processo può risultare vantaggioso in scenari in cui non è possibile allestire infrastrutture costruttive tradizionali (es. gole alpine, foreste). Tendendo conto dei vincoli e delle caratteristiche del sistema di fabbricazione proposto, sono state esplorate potenzialità e criticità del sistema studiato.

Documentation of glaciers and mountain chains in the Nordvestfjord of Scorsby Sound (East Greenland, July 2016) by landscape photography during Maria S. Merian cruise MSM56

From the 12th until the 17th of July 2016, research vessel Maria S. Merian entered the Nordvestfjord of Scorsby Sound (East Greenland) as part of research cruise MSM56, "Ecological chemistry in Arctic fjords". A large variety of chemical and biological parameters of fjord and meltwater were measured during this cruise to characterize biogeochemical fluxes in arctic fjords. The photo documentation described here was a side project. It was started when we were close to the Daugaard-Jensen glacier at the end of the Nordvestfjord and realized that not many people have seen this area before and photos available for scientists are probably rare. These pictures shall help to document climate and landscape changes in a remote area of East Greenland. Pictures were taken with a Panasonic Lumix G6 equipped with either a 14-42 or 45-150 objective (zoom factor available in jpg metadata). Polarizer filters were used on both objectives. The time between taking the pictures and writing down the coordinates was maximally one minute but usually shorter. The uncertainty in position is therefore small as we were steaming slowly most of the time the pictures were taken (i.e. below 5 knots). I assume the uncertainty is in most cases below 200 m radius of the noted position. I did not check the direction I directed the camera to with a compass at the beginning. Hence, the direction that was noted is an approximation based on the navigation map and the positioning of the ship. The uncertainty was probably around +/- 40° but initially (pictures 1-17) perhaps even higher as this documentation was a spontaneous idea and it took some time to get the orientation right. It should be easy, however, to find the location of the mountains and glaciers when being on the respective positions because the mountains have a quite characteristic shape. In a later stage of this documentation, I took pictures from the bridge and used the gyros to approximate the direction the camera was pointed at. Here the uncertainty was much lower (i.e. +/- 20° or better). Directions approximated with the help of gyros have degree values in the overview table. The ship data provided in the MSM56 cruise report will contain all kinds of sensor data from Maria S. Merian sensor setup. This data can also be used to further constrain the position the pictures were taken because the exact time a photo was shot is noted in the metadata of the .jpg photo file. The shipboard clock was set on UTC. It was 57 minutes and 45 seconds behind the time in the camera. For example 12:57:45 on the camera was 12:00:00 UTC on the ship. All pictures provided here can be used for scientific purposes. In case of usage in presentations etc. please acknowledge RV Maria S. Merian (MSM56) and Lennart T. Bach as author. Please inform me and ask for reprint permission in case you want to use the pictures for scientific publications. I would like to thank all participants and the crew of Maria S. Merian Cruise 56 (MSM56, Ecological chemistry in Arctic fjords).

Photography student working in darkroom

Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].

Photography student working in darkroom

Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].

Aerial photo of SRS-4, Shark River Slough

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

Renouncing the Single Image: Photography and the Realism of Abstraction

This essay addresses the issue of the relationship between abstraction and realism that it argues is at stake in the rejection of any primacy accorded to the single image, in favour of a sequencing of photographs according to certain, often novelistic and epic ideas of narrative form. Setting out from the opening text of Allan Sekula’s Fish Story, the article explores the competing tendencies towards what Georg Lukács termed ‘narration’ and ‘description’ as these are traced throughout Sekula's project (in part through a comparison with the contrasting works of Andreas Gursky). The essay concludes by suggesting the ways in which it is the irreducible actuality of abstraction within the concrete everydayness of capitalism's social world that means that all photographic ‘realism’ is intrinsically ‘haunted’ by a certain spectre of that ‘self-moving substance in the ‘shape of money’, as Marx calls it, or of the abstract form of capital itself.

High Formalism: The aerial view and the colour field

Laura Kurgan’s Monochrome Landscapes (2004), first exhibited in the Whitney Museum of American Art in New York City, consists of four oblong Cibachrome prints derived from digital files sourced from the commercial Ikonos and QuickBird satellites. The prints are ostensibly flat, depthless fields of white, green, blue, and yellow, yet the captions provided explain that the sites represented are related to contested military, industrial, and cartographic practices. In Kurgan’s account of Monochrome Landscapes she explains that it is in dialogue with another work from the Whitney by abstract artist Ellsworth Kelly. This article pursues the relationship between formalist abstraction and satellite imaging in order to demonstrate how formalist strategies aimed at producing an immediate retinal response are bound up with contemporary uses of digital information and the truth claims such information can be made to substantiate.

‘Don’t look down!’: A short history of rooftopping photography

The article examines the practice known as ‘rooftopping photography’ and its significance for the representation of vertical cities. It begins by charting the historical development of architecture as a viewing platform in the age of the camera, and dwells on the imagery of cityscapes from above that emerged in the inter-war period. Against this background, the essay investigates how rooftopping arose out of the urban exploration movement and became a global trend in the early 2010s. This phenomenon is situated within its wider social and cultural context, and is discussed with reference to the online media discourse that contributed to its public visibility. A set of ideas from the philosophy of photography and visual culture inform the critical analysis of rooftopping photographs: this broad and diverse body of images is examined with a focus on two predominant modes of representation—panoramic and plunging views. The affective responses elicited by so-called ‘vertigo-inducing’ images are discussed through the concept of vicarious kinaesthesia, which offers insights into the nexus between visceral experience and visual representation that lies at the core of rooftopping. By unpacking this interplay, the essay explores a phenomenon that has hitherto been given little scholarly attention and reflects on its broader implications for the relationship between photography and architecture today.

Spanish Photography Yearbooks between the Autarchy and the Transition A Documentary Analysis (1958-1980)

The first yearbook on Spanish artistic photography was published in 1924 and following the Civil War of 1936-1939, Madrid’s Real Sociedad Fotográfica, through its Sombras magazine, published two others in 1946 and 1948. There would not be another publication until 1958, when the Agrupación Fotográfica Almeriense put out the third yearbook, during a period of economic recovery following the country’s admission to the U.N. at the end of 1955. However, it was not until 1972 when Spanish photography resumed the publication of annual summaries of the authors and their works. From then on until 1980, nine yearbooks were published by two institutions: The Consorcio del Libro Técnico (Cotec) and the Editorial Everest publishing company. The object of this study is to analyze the contents of these yearbooks in order to determine and furnish new data on the history of Spanish photography: authors, works, publications, national and international relations and the purpose of their publications as a means for supporting photography.

Photography, copyright, and the South Kensington experiment

Reviews the development of UK copyright law in the 19th century concerning photographs of works of art in public collections. Discusses the project at South Kensington Museum to sell photographs of works of art to the public at cost price, and the introduction of copyright protection for original photographs under the Fine Arts Copyright Act 1862. Considers the parliamentary debates on whether photography was worthy of copyright protection. Examines whether lessons should be learned now that digital technology offers the opportunity to improve public access to works of art.

Shared Photography: (Photo)journalism and political mobilisation in Rio de Janeiro's favelas

One of the most important civic phenomena emerging from favelas in Rio de Janeiro today is “community (photo)journalism”, which is practised by favela residents who are trained in journalistic and artistic techniques to raise critical awareness and promote political mobilisation in- and outside favelas. This paper looks at some of the work produced at one training place for community photographers, the agency-school Imagens do Povo (“Images of the People”) in Nova Holanda, a favela located in Rio’s North Zone. Using an ethnographic approach, this article first provides an account of the working practices of the School and its photographers. This is followed by a discussion of a small sample of their photographic work, for which we employ a social semiotic paradigm of image analysis. This methodological synergy provides insights into how these journalists document long-term structural as well as “spectacular” violence in favelas, while at the same time striving to capture some of the “beauty” of these communities. The paper concludes that this form of photographic work constitutes an important step towards a more analytical brand of journalism with different news values that encourage a more context-sensitive approach to covering urban violence and favela life.

KEYWORDS: alternative media, Imagens do Povo, multimodality, news values, photojournalism.