Articles: Recent submissions

Now showing items 41-60 of 70

  • 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 ...

  • Automatic summarization and annotation of videos with lack of metadata information 

    Papadopoulos, Dim P.; Kalogeiton, Vicky S.; Chatzichristofis, Savvas A.; Papamarkos, Nikos (Elsevier, 2013)
    The advances in computer and network infrastructure together with the fast evolution of multimedia data has resulted in the growth of attention to the digital video’s development. The scientific community has increased the ...

  • A Multi-Objective Exploration Strategy for Mobile Robots Under Operational Constraints 

    Amanatiadis, Angelos A.; Chatzichristofis, Savvas A.; Charalampous, Konstantinos; Doitsidis, Lefteris; Kosmatopoulos, Elias B.; Tsalides, Phillipos; Gasterato, Antonios; Roumeliotis, Stergios I. (IEEE, 2013)
    Multi-objective robot exploration constitutes one of the most challenging tasks for autonomous robots performing in various operations and different environments. However, the optimal exploration path depends heavily on ...

  • Content-based image retrieval over IEEE 802.11b noisy wireless networks 

    Chatzistavros, Evaggelos; Chatzichristofis, Savvas A.; Zagoris, Konstatinos; Stamatelos, George (Wiley, 2014)
    Mobile devices such as smartphones and tablets are widely used in everyday life to perform a variety of operations, such as e-mail exchange, connection to social media, bank/financial transactions, and so on. Moreover, ...

  • Image Encryption using the Recursive Attributes of the eXclusive-OR Filter 

    Chatzichristofis, Savvas A.; Marques, Oge; Lux, Mathias; Boutalis, Yiannis (Springer, 2014)
    This paper describes a visual multimedia content encryption approach based on cellular automata (CA), expanding the work proposed in [4]. The presented algorithm relies on an attribute of the eXclusive-OR (XOR) filter, ...

  • Vision-Controlled Micro Flying Robots: From System Design to Autonomous Navigation and Mapping in GPS-Denied Environments 

    Scaramuzza, Davide; Achtelik, Michael; Doitsidis, Lefteris; Fraundorfer, Friedrich; Kosmatopoulos, Elias; Martinelli, Agostino; Achtelik, Markus Wilhelm; Chli, Margarita; Chatzichristofis, Savvas A.; Kneip, Laurent; Gurdan, Daniel; Heng, Lionel; Lee, Gim Hee; Lynen, Simon; Meier, Lorenz; Pollefeys, Marc; Renzaglia, Alessandro; Siegwart, Roland; Stumpf, Jan Carsten; Tanskanen, Petri; Troiani, Chiara; Weiss, Stephan (IEEE, 2014)
    Autonomous micro helicopters are about to play a major role in tasks like search and rescue, environment monitoring, security surveillance, inspection, etc. If they are further realized in small scale, they can also be ...

  • How Smart Are Smartphones?: Bridging the marketing and information technology gap. 

    Amanatiadis, Angelos; Chatzichristofis, Savvas A. (IEEE, 2014)
    The term "smart" has become widespread in consumer electronics in recent years, reflecting the consumers' need for devices that assist them in their daily activities. The term has a long history of usage in marketing science ...

  • Hybrid Cellular Ants for Clustering Problems 

    Bitsakidis, Nikolaos P.; Chatzichristofis, Savvas A.; Sirakoulis, Georgios Ch. (Old City Publishing, 2014)
    In the last decade the amount of the stored data related to almost all areas of life has rapidly increased. However, the overall process of discovering knowledge from data demands more powerful clustering techniques to ...

  • Real-time indexing for large image databases: color and edge directivity descriptor on GPU 

    Bampis, Loukas; Iakovidou, Chryssanthi; Chatzichristofis, Savvas A.; Boutalis, Yiannis S.; Amanatiadis, Angelos (Springer, 2014)
    In this paper, we focus on implementing the extraction of a well-known low-level image descriptor using the multicore power provided by general-purpose graphic processing units (GPGPUs). The color and edge directivity ...

  • Image Moment Invariants as Local Features for Content Based Image Retrieval using the Bag-of-Visual-Words Model 

    Karakasis, Evangelos G.; Amanatiadis, Angelos; Gasteratos, Antonios; Chatzichristofis, Savvas A. (Elsevier, 2015)
    This paper presents an image retrieval framework that uses affine image moment invariants as descriptors of local image areas. Detailed feature vectors are generated by feeding the produced moments into a Bag-of-Visual-Words ...

  • What, Where and How? Introducing pose manifolds for industrial object manipulation 

    Kouskouridas, R.; Amanatiadis, A.; Chatzichristofis, Savvas A.; Gasteratos, A. (Elsevier, 2015)
    In this paper we propose a novel method for object grasping that aims to unify robot vision techniques for 24 efficiently accomplishing the demanding task of autonomous object manipulation. Through ontological 25 concepts, ...

  • Localizing global descriptors for content-based image retrieval 

    Iakovidou, Chryssanthi; Anagnostopoulos, Nektarios; Kapoutsis, Athanasios; Boutalis, Yiannis; Lux, Mathias; Chatzichristofis, Savvas A. (Springer, 2015)
    In this paper, we explore, extend and simplify the localization of the description ability of the well-established MPEG-7 (Scalable Colour Descriptor (SCD), Colour Layout Descriptor (CLD) and Edge Histogram Descriptor ...

  • Real-time adaptive multi-robot exploration with application to underwater map construction 

    Kapoutsis, Athanasios Ch.; Chatzichristofis, Savvas A.; Doitsidis, Lefteris; Borges de Sousa, João; Pinto, Jose; Braga, Jose; Kosmatopoulos, Elias B. (Springer, 2016)
    This paper deals with the problem of autonomous exploration of unknown areas using teams of Autonomous X Vehicles (AXVs)—with X standing for Aerial, Underwater or Sea-surface—where the AXVs have to autonomously navigate ...