120 research outputs found
MusA: Using Indoor Positioning and Navigation to Enhance Cultural Experiences in a museum
In recent years there has been a growing interest into the use of multimedia mobile guides in museum environments. Mobile devices have the capabilities to detect the user context and to provide pieces of information suitable to help visitors discovering and following the logical and emotional connections that develop during the visit. In this scenario, location based services (LBS) currently represent an asset, and the choice of the technology to determine users' position, combined with the definition of methods that can effectively convey information, become key issues in the design process. In this work, we present MusA (Museum Assistant), a general framework for the development of multimedia interactive guides for mobile devices. Its main feature is a vision-based indoor positioning system that allows the provision of several LBS, from way-finding to the contextualized communication of cultural contents, aimed at providing a meaningful exploration of exhibits according to visitors' personal interest and curiosity. Starting from the thorough description of the system architecture, the article presents the implementation of two mobile guides, developed to respectively address adults and children, and discusses the evaluation of the user experience and the visitors' appreciation of these application
Seabed fluid flow-related processes: evidence and quantification based on high-resolution imaging techniques and GIS analyses
This work provides new insights on different aspects of seabed fluid flow processes based on seafloor observations. The methods used entirely rely on ROV-based high-resolution imaging and mapping techniques. Optical data are used to produce visual maps of the seafloor, in the form of geo-referenced video- and photo-mosaics, whereas acoustic techniques allow mapping the micro-bathymetry of the seabed, as well as the signal reflectivity of the sediment surface and of the water column. This work presents three case studies, about two sites of seabed fluid flow: the Menez Gwen hydrothermal vent on the MAR and the REGAB pockmark in the Lower Congo Basin. On the technical side, some of the high-resolution techniques used in this thesis are not commonly used by the marine scientific community. This is particularly the case for large-area photo-mosaics. Although the interest in mosaicking is growing, there are still no tools freely and readily available to scientists to routinely construct large-area photo-mosaics. Therefore, this work presents a MATLAB toolbox for large-area photo-mosaicking (LAPM toolbox), which was developed as part of this thesis
The Exploitation of Data from Remote and Human Sensors for Environment Monitoring in the SMAT Project
In this paper, we outline the functionalities of a system that integrates and
controls a fleet of Unmanned Aircraft Vehicles (UAVs). UAVs have a set of payload sensors
employed for territorial surveillance, whose outputs are stored in the system and analysed
by the data exploitation functions at different levels. In particular, we detail the second
level data exploitation function whose aim is to improve the sensors data interpretation in
the post-mission activities. It is concerned with the mosaicking of the aerial images and
the cartography enrichment by human sensors—the social media users. We also describe
the software architecture for the development of a mash-up (the integration of information
and functionalities coming from the Web) and the possibility of using human sensors in the
monitoring of the territory, a field in which, traditionally, the involved sensors were only the
hardware ones.JRC.H.6-Digital Earth and Reference Dat
High spatial resolution photo mosaicking for the monitoring of coralligenous reefs
AbstractCoralligenous reefs are characterized by large bathymetric and spatial distribution, as well as heterogeneity; in shallow environments, they develop mainly on vertical and sub-vertical rocky walls. Mainly diver-based techniques are carried out to gain detailed information on such habitats. Here, we propose a non-destructive and multi-purpose photo mosaicking method to study and monitor coralligenous reefs developing on vertical walls. High-pixel resolution images using three different commercial cameras were acquired on a 10 m2 reef, to compare the effectiveness of photomosaic method to the traditional photoquadrats technique in quantifying the coralligenous assemblage. Results showed very high spatial resolution and accuracy among the photomosaic acquired with different cameras and no significant differences with photoquadrats in assessing the assemblage composition. Despite the large difference in costs of each recording apparatus, little differences emerged from the assemblage characterization: through the analysis of the three photomosaics twelve taxa/morphological categories covered 97–99% of the sampled surface. Photo mosaicking represents a low-cost method that minimizes the time spent underwater by divers and capable of providing new opportunities for further studies on shallow coralligenous reefs
Recommended from our members
Detecting medusahead (Taeniatherum caput-medusae (L.) Nevski) using high frequency, sequential, globally positioned digital images
Invasive plant species are expanding and transforming vegetative communities across Oregon and throughout the United States. Over the past three decades remote sensing, geographic information system (GIS), and Global Positioning System (GPS) technologies have been integrated to detect and map the distribution of noxious rangeland plants. This study developed low-cost protocols to detect and map Medusahead (Taeniatherum caput-medusae (L.) Nevski) weed infestations using GPS loggers to track aircraft/camera position, altitude, and bearing, as well as Aerial Image Positioning Tool software to geographically rectify and project each aerial image. We then mapped the extent of medusahead in target areas and evaluated patterns of infestation. Flying in a single engine fixed-wing aircraft, images were collected every five seconds, with a total of 10,362 images obtained. All of the aerial images were processed and, on average, 23.9 % of the area was classified as medusahead infested, with 76.1 % without infestation. Each image covered 215 ha (531 acres), with 60% overlap, at a cost of $ 0.54/km². Our study also employed mobile mapping technology to map medusahead on the ground by digitizing infestations using a laptop computer equipped with a GPS antenna and GIS software. Mobile mapping was also done from aircraft, but yielded coarser infestation maps, as the observation distance was greater. These maps covered the full study area. Aerial reconnaissance and mobile survey is cost effective, because thousands of digital images were collected, automatically positioned, and stored
Recommended from our members
Near real-time monitoring of buried oil pipeline right-of-way for third-party incursion
Many security systems employing different methods have been proposed to protect buried oil pipelines transporting petroleum products from the well head via the refinery to: depots and other receiving stations. Currently there is a security gap in the monitoring of these buried pipelines in real time and in keeping them protected from third party interference. This thesis addresses the problem of monitoring these systems by developing an automated image analysis system with the aid of a low-cost multisensory Unmanned Aerial Vehicle (UAV) for monitoring of buried pipeline right-of-way (ROW). The method used in this research is based on the identification of threat objects of interest from the video frame sequences of the pipeline right-of-way acquired by the UAV. This is achieved by training the system to recognise objects of interest using trained correlation filters. To determine the geographical location of detected objects, the Video frame sequences captured by the UAV platform were ortho-rectified to form ortho-images which were then mosaicked to form a seamless Digital Surface Model (DSM) covering the test area using a photogrammetry model. The DSM formed from the mosaicking of ortho-images is then emerged with a digital globe for geo-referencing of detected objects. Experiments were carried out on a test field located in United Kingdom and Nigeria, where video and telemetry data were collected, then processed using the techniques created in this research. The results demonstrated that the developed correlation filter was able to detect objects of interest despite the distortions that come with the object image, due to the fact that the expected distortion was compensated for using the training images. When compared with the 6 control points in the digital globe the accuracy of the two-dimension DSM gave a misalignment error of between 2 and 3 metres
A high resolution digital system for automated aerial surveying.
Thesis (MSc.)- University of Natal,Pietermaritzburg, 2000.Resource managers frequently require moderate to high resolution imagery within short turnaround
periods for use in a GIS-based management system. These spatial data can greatly enhance
their ability to make timely, cost-saving decisions and recommendations.
MBB Consulting Engineers, Inc., of Pietermaritzburg, South Africa had for many years made use
of airborne videography to provide the imagery for several resource-based applications.
Applications included detailed land use mapping in various South African river catchments and
identification, density classification and mapping of alien vegetation. While the system was low
cost and easy to operate, MBB had found that their system was inherently limited, particularly by
its lack of automation and poor spatial resolution. This project was started because of a need to
address these limitations and provide an airborne remote sensing system that was more automated
and could produce higher resolution imagery than the existing system. In addition, the overall cost
and time required to produce a map of the resource of interest needed to be reduced.
The system developed in this project aimed to improve upon the pre-flight planning and in-flight
image acquisition aspects of the existing system. No new post-flight image processing procedures
were developed, but possible future refinement of the post-flight image processing routine was
considered throughout the development of the system. A pre-flight planning software package was
developed that could quickly and efficiently calculate the positions offlight lines and photographs
or images with a minimum of user input. The in-flight image acquisition setup developed involved
the integration of a high resolution digital still camera, a Global Positioning System (GPS), and
camera control software. The use of the rapidly developing and improving technology of a digital
still camera was considered to be a better alternative than a video graphic or traditional film camera
system for a number of reasons. In particular, digital still cameras produce digital imagery without
the need for development and scanning of aerial photographs or frame grabbing of video images.
Furthermore, the resolution of current digital still cameras is already significantly better than that
of video cameras and is rivalling the resolution of 35rnm film.
The system developed was tested by capturing imagery of an urban test area. The images obtained
were then rectified using photogrammetric techniques. Results obtained were promising with
planimetric accuracies of 5 to 1 Om being obtained. From this test it was concluded that for high accuracy applications involving numerous images, use would be made of softcopy
photogrammetric software to semi-automatically position and rectify images, while for
applications requiring fewer images and lower accuracy, images could be rectified using the
simpler technique of assigning GCPs for each image from scanned orthophotos
Advances in Simultaneous Localization and Mapping in Confined Underwater Environments Using Sonar and Optical Imaging.
This thesis reports on the incorporation of surface information into a probabilistic simultaneous localization and mapping (SLAM) framework used on an autonomous underwater vehicle (AUV) designed for underwater inspection. AUVs operating in cluttered underwater environments, such as ship hulls or dams, are commonly equipped with Doppler-based sensors, which---in addition to navigation---provide a sparse representation of the environment in the form of a three-dimensional (3D) point cloud. The goal of this thesis is to develop perceptual algorithms that take full advantage of these sparse observations for correcting navigational drift and building a model of the environment. In particular, we focus on three objectives. First, we introduce a novel representation of this 3D point cloud as collections of planar features arranged in a factor graph. This factor graph representation probabalistically infers the spatial arrangement of each planar segment and can effectively model smooth surfaces (such as a ship hull). Second, we show how this technique can produce 3D models that serve as input to our pipeline that produces the first-ever 3D photomosaics using a two-dimensional (2D) imaging sonar. Finally, we propose a model-assisted bundle adjustment (BA) framework that allows for robust registration between surfaces observed from a Doppler sensor and visual features detected from optical images. Throughout this thesis, we show methods that produce 3D photomosaics using a combination of triangular meshes (derived from our SLAM framework or given a-priori), optical images, and sonar images. Overall, the contributions of this thesis greatly increase the accuracy, reliability, and utility of in-water ship hull inspection with AUVs despite the challenges they face in underwater environments.
We provide results using the Hovering Autonomous Underwater Vehicle (HAUV) for autonomous ship hull inspection, which serves as the primary testbed for the algorithms presented in this thesis. The sensor payload of the HAUV consists primarily of: a Doppler velocity log (DVL) for underwater navigation and ranging, monocular and stereo cameras, and---for some applications---an imaging sonar.PhDElectrical Engineering: SystemsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/120750/1/paulozog_1.pd
- …