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    Wyświetlanie 1-5 z 5
    Tytuł:
    Recognition of Data Matrix codes in images and their applications in production processes
    Autorzy:
    Karrach, Ladislav
    Pivarčiová, Elena
    Powiązania:
    https://bibliotekanauki.pl/articles/409791.pdf
    Data publikacji:
    2020
    Wydawca:
    STE GROUP
    Tematy:
    adaptive thresholding
    connected component labelling
    data matrix code
    finder pattern
    timing pattern
    Opis:
    Data Matrix codes can be a significant factor in increasing productivity and efficiency in production processes. An important point in deploying Data Matrix codes is their recognition and decoding. In this paper is presented a computationally efficient algorithm for locating Data Matrix codes in the images. Image areas that may contain the Data Matrix code are to be identified firstly. To identify these areas, the thresholding, connected components labelling and examining outer bounding-box of the continuous regions is used. Subsequently, to determine the boundaries of the Data Matrix code more precisely, we work with the difference of adjacent projections around the Finder Pattern. The dimensions of the Data Matrix code are determined by analyzing the local extremes around the Timing Pattern. We verified the proposed method on a testing set of synthetic and real scene images and compared it with the results of other open-source and commercial solutions. The proposed method has achieved better results than competitive commercial solutions.
    Źródło:
    Management Systems in Production Engineering; 2020, 3 (28); 154-161
    2299-0461
    Pojawia się w:
    Management Systems in Production Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Automatyczna detekcja płaszczyzn w chmurze punktów w oparciu o algorytm RANSAC i elementy teorii grafów
    RANSAC algorithm and elements of graph thory for automatic plane detection in 3D point cloud
    Autorzy:
    Poręba, M.
    Goulette, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/129757.pdf
    Data publikacji:
    2012
    Wydawca:
    Stowarzyszenie Geodetów Polskich
    Tematy:
    chmura punktów
    segmentacja
    RANSAC
    graf
    algorytm najbliższego sąsiada
    etykietowanie
    spójny komponent
    point cloud
    segmentation
    graph
    k-nearest neighbour algorithm
    labelling
    connected component
    Opis:
    Artykuł przedstawia metodę automatycznego wyodrębniania punktów modelujących płaszczyzny w chmurach punktów pochodzących z mobilnego bądź statycznego skaningu laserowego. Zaproponowany algorytm bazuje na odpornym estymatorze RANSAC umożliwiającym iteracyjną detekcję płaszczyzn w zbiorze cechującym się znacznym poziomem szumu pomiarowego i ilością punktów odstających. Aby zoptymalizować jego działanie, dla każdej wykrytej płaszczyzny uwzględniono relacje sąsiedztwa pomiędzy punktami przynależnymi. W tym celu zastosowano podejście oparte na teorii grafów, gdzie chmura punktów traktowana jest jako graf nieskierowany, dla którego poszukiwane są spójne składowe. Wprowadzona modyfikacja obejmuje dwa dodatkowe etapy: ustalenie najbliższych sąsiadów dla każdego punktu wykrytej płaszczyzny wraz z konstrukcją listy sąsiedztwa oraz etykietowanie spójnych komponentów. Rezultaty uzyskane pokazują iż algorytm poprawnie wykrywa płaszczyzny modelujące, przy czym niezbędny jest odpowiedni dobór parametrów początkowych. Czas przetwarzania uzależniony jest przede wszystkim od liczby punktów w chmurze. Nadal jednak aktualny pozostaje problem wrażliwości algorytmu RANSAC na niską gęstość chmury oraz nierównomierne rozmieszczenie punktów.
    Laser scanning techniques play very important role in acquiring of spatial data. Once the point cloud is available, the data processing must be performed to achieve the final products. The segmentation is an inseparable step in point cloud analysis in order to separate the fragments of the same semantic meaning. Existing methods of 3D segmentation are divided into two categories. The first family contains algorithms functioning on principle of fusion, such as surface growing approach or split-merge algorithm. The second group consists of techniques making possible the extraction of features defined by geometric primitives i.e.: sphere, cone or cylinder. Hough transform and RANSAC algorithm (RANdom SAmple Consensus) are classified to the last of aforementioned groups. This paper studies techniques of point cloud segmentation such as fully automatic plane detection. Proposed method is based on RANSAC algorithm providing an iterative plane modelling in point cloud affected by considerable noise. The algorithm is implemented sequentially, therefore each successive plane represented by the largest number of points is separated. Despite all advantages of RANSAC, it sometimes gives erroneous results. The algorithm looks for the best plane without taking into account the particularity of the object. Consequently, RANSAC may combine points belonging to different objects into one single plane. Hence, RANSAC algorithm is optimized by analysing the adjacency relationships of neighbouring points for each plane. The approach based on graph theory is thus proposed, where the point cloud is treated as undirected graph for which connected components are extracted. Introduced method consists of three main steps: identification of k-nearest neighbours for each point of detected plane, construction of adjacency list and finally connected component labelling. Described algorithm was tested with raw point clouds, unprocessed in sense of filtration. All the numerical tests have been performed on real data, characterized by different resolutions and derived from both mobile and static laser scanning techniques. Obtained results show that proposed algorithm properly separates points for particular planes, whereas processing time is strictly dependent on number of points within the point cloud. Nevertheless, susceptibility of RANSAC algorithm to low point cloud density as well as irregular points distribution is still animportant problem. This paper contains literature review in subject of existing methods for plane detection in data set. Moreover, the description for proposed algorithm based on RANSAC, its principle, as well as the results is also presented.
    Źródło:
    Archiwum Fotogrametrii, Kartografii i Teledetekcji; 2012, 24; 301-310
    2083-2214
    2391-9477
    Pojawia się w:
    Archiwum Fotogrametrii, Kartografii i Teledetekcji
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Real-time Foreground Object Detection Combining the PBAS Background Modelling Algorithm and Feedback from Scene Analysis Module
    Autorzy:
    Kryjak, T.
    Komorkiewicz, M.
    Gorgon, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/225985.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    PBAS algorithm
    foreground segmentation
    foreground object detection
    background generation
    background subtraction
    background modelling
    image processing
    image analysis
    FPGA
    connected component analysis
    consecutive frame diffrencing
    Opis:
    The article presents a hardware implementation of the foreground object detection algorithm PBAS (Pixel-Based Adaptive Segmenter) with a scene analysis module. A mechanism for static object detection is proposed, which is based on consecutive frame differencing. The method allows to distinguish stopped foreground objects (e.g. a car at the intersection, abandoned luggage) from false detections (so-called ghosts) using edge similarity. The improved algorithm was compared with the original version on popular test sequences from the changedetection.net dataset. The obtained results indicate that the proposed approach allows to improve the performance of the method for sequences with the stopped objects. The algorithm has been implemented and successfully verified on a hardware platform with Virtex 7 FPGA device. The PBAS segmentation, consecutive frame differencing, Sobel edge detection and advanced one-pass connected component analysis modules were designed. The system is capable of processing 50 frames with a resolution of 720×576 pixels per second.
    Źródło:
    International Journal of Electronics and Telecommunications; 2014, 60, 1; 61-72
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Edge-Connectivity and Edges of Even Factors of Graphs
    Autorzy:
    Haghparast, Nastaran
    Kiani, Dariush
    Powiązania:
    https://bibliotekanauki.pl/articles/31343450.pdf
    Data publikacji:
    2019-05-01
    Wydawca:
    Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
    Tematy:
    3-edge-connected graph
    2-edge-connected graph
    even factor
    component
    Opis:
    An even factor of a graph is a spanning subgraph in which each vertex has a positive even degree. Jackson and Yoshimoto showed that if G is a 3-edge-connected graph with |G| ≥ 5 and v is a vertex with degree 3, then G has an even factor F containing two given edges incident with v in which each component has order at least 5. We prove that this theorem is satisfied for each pair of adjacent edges. Also, we show that each 3-edge-connected graph has an even factor F containing two given edges e and f such that every component containing neither e nor f has order at least 5. But we construct infinitely many 3-edge-connected graphs that do not have an even factor F containing two arbitrary prescribed edges in which each component has order at least 5.
    Źródło:
    Discussiones Mathematicae Graph Theory; 2019, 39, 2; 357-364
    2083-5892
    Pojawia się w:
    Discussiones Mathematicae Graph Theory
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Grid synchronization and symmetrical components extraction with PLL algorithm for grid connected power electronic converters - a review
    Autorzy:
    Bobrowska-Rafał, M.
    Rafał, K.
    Jasiński, M.
    Kaźmierkowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/200073.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    phase locked loop PLL
    symmetrical component extraction
    grid synchronization
    grid-connected converter
    smart grid
    renewable energy sources (RES)
    voltage dip
    higher harmonics
    power quality
    Opis:
    In this paper, a review of Phase Locked Loop (PLL) algorithms and symmetrical component extraction methods intended for grid-connected power electronic converters are presented. Proposed classification is based on voltage representation in three coordinates: natural (abc), stationary (alfa beta) and rotating coordinates (dq). The three selected algorithms are described in details: Dual Second Order Generalized Integrator (DSOGI-PLL), Dual Virtual Flux – both in stationary coordinates. The third one, in rotating dq coordinates, is Dual Synchronous Reference Frame PLL (DSRF-PLL). A comparison of PLL algorithms is presented. Also, selected experimental results are given to verify practical application of discussed algorithms.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 4; 485-497
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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