21,594 research outputs found

    Optimal Camera Placement to measure Distances Conservativly Regarding Static and Dynamic Obstacles

    Get PDF
    In modern production facilities industrial robots and humans are supposed to interact sharing a common working area. In order to avoid collisions, the distances between objects need to be measured conservatively which can be done by a camera network. To estimate the acquired distance, unmodelled objects, e.g., an interacting human, need to be modelled and distinguished from premodelled objects like workbenches or robots by image processing such as the background subtraction method. The quality of such an approach massively depends on the settings of the camera network, that is the positions and orientations of the individual cameras. Of particular interest in this context is the minimization of the error of the distance using the objects modelled by the background subtraction method instead of the real objects. Here, we show how this minimization can be formulated as an abstract optimization problem. Moreover, we state various aspects on the implementation as well as reasons for the selection of a suitable optimization method, analyze the complexity of the proposed method and present a basic version used for extensive experiments.Comment: 9 pages, 10 figure

    Early Detection of Near-Surface Void Defects in Concrete Pavement Using Drone Based Thermography and GPR Methods

    Get PDF
    The goal of this research is to evaluate the feasibility and the performance of using UAV-mounted infrared thermography (IRT) and ground penetration radar (GPR) to detect sub-surface voids caused by consolidation issues in concrete pavement. The motivation of the study is to identify the consolidation defects as early as the initial set of concrete to avoid having this problem in large pavement sections, which is costly and time consuming to repair. Using the two technologies in combination to detect subsurface voids in the concrete initial set stage is new and aims to take advantage of the strengths and minimize the limitations of each method. UAV-based IRT can cover large areas of the pavements in a short amount of time, while GPR can provide higher accuracy in locating the defects horizontally and vertically. Therefore, the combination of the two technologies can allow detection of small voids in large areas with improved confidence. In this project, both laboratory and field tests were conducted with both methods, and coring samples were used for validation of results. The results from multiple specimens and multiple experiments suggested that both technologies performed well in detecting the subsurface voids in the concrete pavement’s initial set stage. Despite some limitations discussed in the report, the outcomes of the project provided evidence that these technologies can be used separately or together on the field as efficient and economical quality control tools in concrete pavement construction

    Linear Quadrupole Focusing for High Resolution Microdroplet-Based Fabrication

    Get PDF
    In industry, particularly in the field of rapid prototyping, droplet-based manufacturing is proving to be an extremely efficient technique for the production of low cost electronic components. However, for some applications, the desired material properties at deposition are not easily integrated with a homogeneous, low viscosity fluid suitable for droplet ejection. For this reason, it would prove beneficial to have some means of altering the material properties of the droplets during their travel to the substrate. Due to the inherent irregularities in droplet ejection systems, increases in the associated throw-distances and travel times generally cause decreased resolution in placement. Thus, the purpose of this study was to assess the potential of a linear electrodyamic quadrupole for use in constraining the trajectories of charged microdroplets to allow for modification of their material properties prior to deposition. The equations of motion for the droplets within the device were derived and integrated numerically. Approximate bounds on the system stability were determined and the effects of the respective parameters were considered. An experimental system was constructed and used for deposition experiments. The results obtained, show that a linear quadrupole can be used to focus microdroplet streams for deposition, and that the corresponding operating variables can be predicted from the governing equations

    Project Report on Development of a Safeguards Approach for Pyroprocessing

    Get PDF
    The Idaho National Laboratory has undertaken an effort to develop a standard safeguards approach for international commercial pyroprocessing facilities. This report details progress for the fiscal year 2010 effort. A component by component diversion pathway analysis has been performed, and has led to insight on the mitigation needs and equipment development needed for a valid safeguards approach. The effort to develop an in-hot cell detection capability led to the digital cloud chamber, and more importantly, the significant potential scientific breakthrough of the inverse spectroscopy algorithm, including the ability to identify energy and spatial location of gamma ray emitting sources with a single, non-complex, stationary radiation detector system. Curium measurements were performed on historical and current samples at the FCF to attempt to determine the utility of using gross neutron counting for accountancy measurements. A solid cost estimate of equipment installation at FCF has been developed to guide proposals and cost allocations to use FCF as a test bed for safeguards measurement demonstrations. A combined MATLAB and MCNPX model has been developed to perform detector placement calculations around the electrorefiner. Early harvesting has occurred wherein the project team has been requested to provide pyroprocessing technology and safeguards short courses

    Automatic camera selection for activity monitoring in a multi-camera system for tennis

    Get PDF
    In professional tennis training matches, the coach needs to be able to view play from the most appropriate angle in order to monitor players' activities. In this paper, we describe and evaluate a system for automatic camera selection from a network of synchronised cameras within a tennis sporting arena. This work combines synchronised video streams from multiple cameras into a single summary video suitable for critical review by both tennis players and coaches. Using an overhead camera view, our system automatically determines the 2D tennis-court calibration resulting in a mapping that relates a player's position in the overhead camera to their position and size in another camera view in the network. This allows the system to determine the appearance of a player in each of the other cameras and thereby choose the best view for each player via a novel technique. The video summaries are evaluated in end-user studies and shown to provide an efficient means of multi-stream visualisation for tennis player activity monitoring

    Indexing of fictional video content for event detection and summarisation

    Get PDF
    This paper presents an approach to movie video indexing that utilises audiovisual analysis to detect important and meaningful temporal video segments, that we term events. We consider three event classes, corresponding to dialogues, action sequences, and montages, where the latter also includes musical sequences. These three event classes are intuitive for a viewer to understand and recognise whilst accounting for over 90% of the content of most movies. To detect events we leverage traditional filmmaking principles and map these to a set of computable low-level audiovisual features. Finite state machines (FSMs) are used to detect when temporal sequences of specific features occur. A set of heuristics, again inspired by filmmaking conventions, are then applied to the output of multiple FSMs to detect the required events. A movie search system, named MovieBrowser, built upon this approach is also described. The overall approach is evaluated against a ground truth of over twenty-three hours of movie content drawn from various genres and consistently obtains high precision and recall for all event classes. A user experiment designed to evaluate the usefulness of an event-based structure for both searching and browsing movie archives is also described and the results indicate the usefulness of the proposed approach

    Optimized sensor placement for dependable roadside infrastructures

    Full text link
    We present a multi-stage optimization method for efficient sensor deployment in traffic surveillance scenarios. Based on a genetic optimization scheme, our algorithm places an optimal number of roadside sensors to obtain full road coverage in the presence of obstacles and dynamic occlusions. The efficiency of the procedure is demonstrated for selected, realistic road sections. Our analysis helps to leverage the economic feasibility of distributed infrastructure sensor networks with high perception quality.Comment: 6 pages, 5 figures; IEEE Intelligent transportation systems conference 201

    Indexing of fictional video content for event detection and summarisation

    Get PDF
    This paper presents an approach to movie video indexing that utilises audiovisual analysis to detect important and meaningful temporal video segments, that we term events. We consider three event classes, corresponding to dialogues, action sequences, and montages, where the latter also includes musical sequences. These three event classes are intuitive for a viewer to understand and recognise whilst accounting for over 90% of the content of most movies. To detect events we leverage traditional filmmaking principles and map these to a set of computable low-level audiovisual features. Finite state machines (FSMs) are used to detect when temporal sequences of specific features occur. A set of heuristics, again inspired by filmmaking conventions, are then applied to the output of multiple FSMs to detect the required events. A movie search system, named MovieBrowser, built upon this approach is also described. The overall approach is evaluated against a ground truth of over twenty-three hours of movie content drawn from various genres and consistently obtains high precision and recall for all event classes. A user experiment designed to evaluate the usefulness of an event-based structure for both searching and browsing movie archives is also described and the results indicate the usefulness of the proposed approach
    corecore