School of Information Sciences: Recent submissions

Now showing items 101-120 of 163

  • Content Based Image Retrieval Using Visual-Words Distribution Entropy 

    Chatzichristofis, Savvas A.; Iakovidou, Chrysanthi; Boutalis, Yiannis (Springer, 2011)
    Bag-of-visual-words (BOVW) is a representation of images which is built using a large set of local features. To date, the experimental results presented in the literature have shown that this approach achieves high retrieval ...

  • Video Summarization Using a Self-Growing and Self-Organized Neural Gas Network 

    Papadopoulos, Dim. P.; Papamarkos, Nikos (Springer, 2011)
    In this paper, a novel method to generate video summaries is proposed, which is allocated mainly for being applied to on-line videos. The novelty of this approach lies in the fact that the video summarization problem is ...

  • The TREC files: the (ground) truth is out there 

    Chatzichristofis, Savvas A.; Zagoris, Konstantinos; Arampatzis, Avi (Association for Computing Machinery (ACM), United States, 2011)
    Traditional tools for information retrieval (IR) evaluation, such as TREC’s trec_eval, have outdated command-line interfaces with many unused features, or ‘switches’, accumulated over the years. They are usually seen ...

  • Combining Color and Spatial Color Distribution Information in a Fuzzy Rule Based Compact Composite Descriptor 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis S.; Lux, Mathias (Springer, 2011)
    In this paper, a novel low level feature for content based image retrieval is presented. The proposed feature structure combines color and spatial color distribution information. The combination of these two features in ...

  • Employing Cellular Automata for Shaping Accurate Morphology Maps Using Scattered Data from Robotics’ Missions 

    Kapoutsis, Athanasios Ch.; Chatzichristofis, Savvas A.; Sirakoulis, Georgios Ch.; Doitsidis, Lefteris; Kosmatopoulos, Elias B. (Springer, 2015)
    Accurate maps are essential in the case of robot teams, so that they can operate autonomously and accomplish their tasks efficiently. In this work we present an approach which allows the generation of detailed maps, suitable ...

  • Cellular Automata Ants 

    Bitsakidis, Nikolaos P.; Dourvas, Nikolaos I.; Chatzichristofis, Savvas A.; Sirakoulis, Georgios Ch. (Springer, 2017)
    During the last decades much attention was given to bio-inspired techniques able to successfully handle really complex algorithmic problems. As such Ant Colony Optimization (ACO) algorithms have been introduced as a ...

  • Content based radiology image retrieval using a fuzzy rule based scalable composite descriptor 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis S. (2010)
    The rapid advances made in the field of radiology, the increased frequency in which oncological diseases appear, as well as the demand for regular medical checks, led to the creation of a large database of radiology ...

  • Accurate Image Retrieval Based on Compact Composite Descriptors and Relevance Feedback Information 

    Chatzichristofis, Savvas A.; Zagoris, Konstantinos; Boutalis, Yiannis S.; Papamarkos, Nikos (World Scientific Publishing Company, 2010)
    In this paper a new set of descriptors appropriate for image indexing and retrieval is proposed. The proposed descriptors address the tremendously increased need for e±cient content-based image retrieval (CBIR) in many ...

  • Investigating the Behavior of Compact Composite Descriptors in Early Fusion, Late Fusion and Distributed Image Retrieval 

    Chatzichristofis, Savvas A.; Arampatzis, Avi; Boutalis, Yiannis S. (2010)
    In Content-Based Image Retrieval (CBIR) systems, the visual content of the images is mapped into a new space named the feature space. The features that are chosen must be discriminative and sufficient for the description ...

  • A novel cellular automata based technique for visual multimedia content encryption 

    Chatzichristofis, Savvas A.; Mitzias, Dimitris A.; Sirakoulis, Georgios Ch.; Boutalis, Yiannis S. (Elsevier, 2010)
    This paper proposes a new method for visual multimedia content encryption using Cellular Automata (CA). The encryption scheme is based on the application of an attribute of the CLF XOR filter, according to which the original ...

  • Fast Retrieval from Image Databases via Binary Haar Wavelet Transform on the Color and Edge Directivity Descriptor 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis S.; Arampatzis, Avi (IARIA, 2011)
    In this paper, we are evaluating several accelerating techniques for content-based image retrieval, suitable for the Color and Edge Directivity Descriptor (CEDD). To date, the experimental results presented in the ...

  • Text localization using standard deviation analysis of structure elements and support vector machines 

    Zagoris, Konstantinos; Chatzichristofis, Savvas A.; Papamarkos, Nikos (Springer, 2011)
    A text localization technique is required to successfully exploit document images such as technical articles and letters. The proposed method detects and extracts text areas from document images. Initially a connected ...

  • Dynamic two-stage image retrieval from large multimedia databases 

    Arampatzis, Avi; Zagoris, Konstantinos; Chatzichristofis, Savvas A. (Elsevier, 2013)
    Content-based image retrieval (CBIR) with global features is notoriously noisy, especially for image queries with low percentages of relevant images in a collection. Moreover, CBIR typically ranks the whole collection, ...

  • Co.Vi.Wo.: Color Visual Words Based on Non-Predefined Size Codebooks 

    Chatzichristofis, Savvas A.; Iakovidou, Chryssanthi; Boutalis, Yiannis; Marques, Oge (IEEE, 2012)
    Due to the rapid development of information technology and the continuously increasing number of available multimedia data, the task of retrieving information based on visual content has become a popular subject of scientific ...

  • Mean Normalized Retrieval Order (MNRO): a new content-based image retrieval performance measure 

    Chatzichristofis, Savvas A.; Iakovidou, Chryssanthi; Boutalis, Yiannis S.; Angelopoulou, Elli (Springer, 2014)
    The results of a content based image retrieval system can be evaluated by several performance measures, each one employing different evaluation criteria. Many of the methods used in the field of information retrieval have ...

  • Bag-of-visual-words vs global image descriptors on two-stage multimodal retrieval 

    Zagoris, Konstantinos; Chatzichristofis, Savvas A.; Arampatzis, Avi (ACM SIGIR 2011, 2011)
    The Bag-Of-Visual-Words (BOVW) paradigm is fast becoming a popular image representation for Content-Based Image Retrieval (CBIR), mainly because of its better retrieval effectiveness over global feature representations ...

  • Comparative Performance Evaluation of Image Descriptors Over IEEE 802.11b NoisyWireless Networks 

    Chatzistavros, Evaggelos; Chatzichristofis, Savvas A.; Stamatellos, Georgios; Zagoris, Konstantinos (IEEE (Computer Society), 2011)
    Abstract—In this paper we evaluate the image retrieval procedure over an IEEE 802.11b Ad Hoc network, operating in 2.4GHz, using IEEE Distributed Coordination Function CSMA/CA as the multiple access scheme. IEEE 802.11 ...

  • Fusion vs. Two-Stage for Multimodal Retrieval 

    Arampatzis, Avi; Zagoris, Konstantinos; Chatzichristofis, Savvas A. (Springer, 2011)
    We compare two methods for retrieval from multimodal collections. The first is a score-based fusion of results, retrieved visually and textually. The second is a two-stage method that visually re-ranks the top-K results ...

  • Dynamic Two-Stage Image Retrieval from Large Multimodal Databases 

    Arampatzis, Avi; Zagoris, Konstantinos; Chatzichristofis, Savvas A. (Springer-Verlag, 2011)
    Content-based image retrieval (CBIR) with global features is notoriously noisy, especially for image queries with low percentages of relevant images in a collection. Moreover, CBIR typically ranks the whole collection, ...

  • www.MMRetrieval.net: a multimodal search engine 

    Zagoris, Konstantinos; Chatzichristofis, Savvas A.; Arampatzis, Avi (Association for Computing Machinery (ACM), United States, 2010)
    We introduce an experimental search engine for multilin- gual and multimedia information, employing a holistic web interface and enabling the use of highly distributed indices. Modalities are searched in parallel, and ...