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  • 1.
    Alqaysi, Hiba
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawal, Najeem
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Fedorov, Igor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Evaluating Coverage Effectiveness of Multi-Camera Domes Placement for Volumetric Surveillance2017In: ICDSC 2017 Proceedings of the 11th International Conference on Distributed Smart Cameras, New York, NY, USA: Association for Computing Machinery (ACM), 2017, Vol. F132201, p. 49-54Conference paper (Refereed)
    Abstract [en]

    Multi-camera dome is composed of a number of cameras arranged to monitor a half sphere of the sky. Designing a network of multi-camera domes can be used to monitor flying activities in open large area, such as birds' activities in wind parks. In this paper, we present a method for evaluating the coverage effectiveness of the multi-camera domes placement in such areas. We used GPS trajectories of free flying birds over an area of 9 km2 to analyze coverage effectiveness of randomly placed domes. The analysis is based on three criteria namely, detection, positioning and the maximum resolution captured. The developed method can be used to evaluate results of designing and optimizing dome placement algorithms for volumetric monitoring systems in order to achieve maximum coverage.

  • 2.
    Alqaysi, Hiba
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawal, Najeem
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Fedorov, Igor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Full Coverage Optimization for Multi Camera Dome Placement in Volumetric Monitoring2018In: ACM International Conference Proceeding Series, New York, NY, USA: ACM Digital Library, 2018, article id Article No. 2Conference paper (Refereed)
    Abstract [en]

    Volumetric monitoring can be challenging due to having a 3D target space and moving objects within it. Multi camera dome is proposed to provide a hemispherical coverage of the 3D space around it. This paper introduces a method that optimizes multi camera placement for full coverage in volumetric monitoring system. Camera dome placement is modeled in a volume by adapting the hexagonal packing of circles to provide full coverage at a given height, and 100% detection of flying objects within it. The coverage effectiveness of different placement configurations was assessed using an evaluation environment. The proposed placement is applicable in designing and deploying surveillance systems for remote outdoor areas, such as sky monitoring in wind farms and airport runways in order to record and analyze flying activities.

  • 3.
    Alqaysi, Hiba
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawal, Najeem
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Fedorov, Igor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thörnberg, Benny
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Cost Optimized Design of Multi-Camera Domefor Volumetric Surveillance2021In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 21, no 3, p. 3730-3737Article in journal (Refereed)
    Abstract [en]

    A multi-camera dome consists of number ofcameras arranged in layers to monitor a hemisphere aroundits center. In volumetric surveillance,a 3D space is required tobemonitoredwhich can be achievedby implementing numberof multi-camera domes. A monitoring height is consideredas a constraint to ensure full coverage of the space belowit. Accordingly, the multi-camera dome can be redesignedinto a cylinder such that each of its multiple layers hasdifferent coverage radius. Minimum monitoring constraintsshould be met at all layers. This work is presenting a costoptimized design for the multi-camera dome that maximizesits coverage. The cost per node and number of squaremetersper dollar of multiple configurations are calculated using asearch space of cameras and considering a set of monitoring and coverage constraints. The proposed design is costoptimized per node and provides more coverage as compared to the hemispherical multi-camera dome.

  • 4.
    Alqaysi, Hiba
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawal, Najeem
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Fedorov, Igor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thörnberg, Benny
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Design Exploration of Multi-Camera Dome2019In: ICDSC 2019 Proceedings of the 13th International Conference on Distributed Smart Cameras, New York, NY: ACM Digital Library, 2019, article id Article No. 7aConference paper (Refereed)
    Abstract [en]

    Visual monitoring systems employ distributed smart cameras toeffectively cover a given area satisfying specific objectives. Thechoice of camera sensors and lenses and their deployment affectsdesign cost, accuracy of the monitoring system and the ability toposition objects within the monitored area. Design cost can bereduced by investigating deployment topology such as groupingcameras together to form a dome at a node and optimize it formonitoring constraints. The constraints may include coverage area,number of cameras that can be integrated in a node and pixelresolution at a given distance. This paper presents a method foroptimizing the design cost of multi-camera dome by analyzing tradeoffsbetween monitoring constraints. The proposed method can beused to reduce monitoring cost while fulfilling design objectives.Results show how to increase coverage area for a given cost byrelaxing requirements on design constraints. Multi-camera domescan be used in sky monitoring applications such as monitoring windparks and remote air-traffic control of airports where all-round fieldof view about a point is required to monitor.

  • 5.
    Fedorov, Igor
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawal, Najeem
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Alqaysi, Hiba
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Placement Strategy of Multi-Camera Volumetric Surveillance System for Activities Monitoring2017In: ICDSC 2017 Proceedings of the 11th International Conference on Distributed Smart Cameras, New York, NY, USA: Association for Computing Machinery (ACM), 2017, Vol. F132201, p. 113-118Conference paper (Refereed)
    Abstract [en]

    The design of multi-camera surveillance system comes with many advantages, for example it facilitates as understanding how flying objects act in a given volume. One possible application is for the observation interaction of birds and calculate their trajectories around wind turbines to create promising systems for preventing bird collisions with turbine blades. However, there are also challenges, such as finding the optimal node placement and camera calibration. To address these challenges we investigated a trade-off between calibration accuracy and node requirements, including resolution, modulation transfer function, field of view and angle baseline. We developed a strategy for camera placement to achieve improved coverage for golden eagle monitoring and tracking. This strategy based on the modified resolution criterion taking into account the contrast function of the camera and the estimation of the base angle between the cameras.

  • 6.
    Fedorov, Igor
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawal, Najeem
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thörnberg, Benny
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Alqaysi, Hiba
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Towards calibration of outdoor multi-camera visual monitoring system2018In: ACM International Conference Proceeding Series, New York, NY, US: ACM Digital Library, 2018, , p. 6Conference paper (Refereed)
    Abstract [en]

    This paper proposes a method for calibrating of multi-camera systems where no natural reference points exist in the surrounding environment. Monitoring the air space at wind farms is our test case. The goal is to monitor the trajectories of flying birds to prevent them from colliding with rotor blades. Our camera calibration method is based on the observation of a portable artificial reference marker made out of a pulsed light source and a navigation satellite sensor module. The reference marker can determine and communicate its position in the world coordinate system at centimeter precision using navigartion sensors. Our results showed that simultaneous detection of the same marker in several cameras having overlapping field of views allowed us to determine the markers position in 3D world coordinate space with an accuracy of 3-4 cm. These experiments were made in the volume around a wind turbine at distances from cameras to marker within a range of 70 to 90 m.

  • 7.
    Fedorov, Igor
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Thörnberg, Benny
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Alqaysi, Hiba
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Lawaly, Najeem
    HIAB AB.
    O'Nils, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    A two-layer 3D reconstruction method and calibration for multi-camera-based volumetric positioning and characterization2021In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 70, article id 9193913Article in journal (Refereed)
    Abstract [en]

    A three-dimensional (3D) reconstruction method and multi-camera calibration using multiple artificial reference markers have been used for precise volumetric surveillance of fast-flying objects. The method uses a two-layer 3D reconstruction that integrates two multi-camera stereo-nodes. The fields of view of stereo nodes are directed at an acute angles to each other to provide greater coverage with the given constraints and to determine the flight characteristics of objects in 3D. The object’s flight reconstruction includes a “rough” estimation of its positions relative to selected artificial reference points in both stereo nodes separately and subsequent “refinement” of calculated positions. In this paper, we describe the proposed method and calibration technique, using a multi-camera system to measure object characteristics in 3D. The proposed method applies to volumetric surveillance in situations where it is necessary to count, track, and analyze the activities of flying objects, especially birds, using high spatial resolution.

  • 8.
    Niskanen, Ilpo
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. University of Oulu, Oulu, Finland.
    Forsberg, Viviane
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. KTH.
    Zakrisson, Daniel
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Reza, Salim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Hummelgård, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Fedorov, Igor
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Suopajärvi, Terhi
    University of Oulu, Oulu, Finland.
    Liimatainen, Henrikki
    University of Oulu, Oulu, Finland.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Determination of nanoparticle size using Rayleigh approximation and Mie theory2019In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 201, no 29, p. 222-229Article in journal (Refereed)
    Abstract [en]

    Accurate determination of the size of nanoparticles has an important role in many different scientific and industrial purposes, such as in material, medical and environment sciences, colloidal chemistry and astrophysics. We describe an effective optical method to determine the size of nanoparticles by analysis of transmission and scattering of visible spectral range data from a designed UV-Vis multi-spectrophotometer. The size of the nanoparticles was calculated from the extinction cross section of the particles using Rayleigh approximation and Mie theory. We validated the method using polystyrene nanospheres, cellulose nanofibrils, and cellulose nanocrystals. A good agreement was achieved through graphical analysis between measured extinction cross section values and theoretical Rayleigh approximation and Mie theory predictions for the sizes of polystyrene nanospheres at wavelength range 450 - 750 nm. Provided that Rayleigh approximation's forward scattering (FS)/back scattering (BS) ratio was smaller than 1.3 and Mie theory's FS/BS ratio was smaller than 1.8. A good fit for the hydrodynamic diameter of nanocellulose was achieved using the Mie theory and Rayleigh approximation. However, due to the high aspect ratio of nanocellulose, the obtained results do not directly reflect the actual cross-sectional diameters of the nanocellulose. Overall, the method is a fast, relatively easy, and simple technique to determine the size of a particle by a spectrophotometer. Consequently, the method can be utilized for example in production and quality control purposes as well as for research and development applications.

1 - 8 of 8
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Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
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  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf