Browsing Conference papers by Author "Chatzichristofis, Savvas A."

Now showing items 1-20 of 31

  • Accelerating Image Retrieval Using Binary Haar Wavelet Transform on the Color and Edge Directivity Descriptor 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis; Arampatzis, Avi (Institute of Electrical and Electronics Engineers (IEEE), United States, 2010)
    In this paper, a new accelerating technique for content-based image retrieval is proposed, suitable for the Color and Edge Directivity Descriptor (CEDD). To date, the experimental results presented in the literature ...

  • Automatic Image Annotation and Retrieval Using the Joint Composite Descriptor 

    Zagoris, Konstantinos; Chatzichristofis, Savvas A.; Papamarkos, Nikos; Boutalis, Yiannis (Institute of Electrical and Electronics Engineers (IEEE), United States, 2010)
    Capable tools are needed in order to successfully search and retrieve a suitable image from large image collections. Many content-based image retrieval systems employ low-level image features such as color, texture and ...

  • Autonomous Navigation of Teams of Unmanned Aerial or Underwater Vehicles for Exploration of Unknown Static & Dynamic Environments 

    Kapoutsis, A. Ch.; Chatzichristofis, Savvas A.; Doitsidis, L.; Borges de Sousa, Joao; Kosmatopoulos, E. B. (MED’13, 2013)
    In this paper, we present a new approach that is able to efficiently and fully-autonomously navigate a team of Unmanned Aerial or Underwater Vehicles (UAUV’s) when deployed in exploration of unknown static and dynamic ...

  • 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 ...

  • CEDD: Color and Edge Directivity Descriptor: A Compact Descriptor for Image Indexing and Retrieval 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis (Springer-Verlag, 2008)
    This paper deals with a new low level feature that is extracted from the images and can be used for indexing and retrieval. This feature is called “Color and Edge Directivity Descriptor” and incorporates color and texture ...

  • Color and Edge Directivity Descriptor on GPGPU 

    Iakovidou, Chrysanthi; Bampis, L.; Chatzichristofis, Savvas A.; Boutalis, Yiannis; Amanatiadis, A. (IEEE (Computer Society), 2015)
    Image indexing refers to describing the visual multimedia content of a medium, using high level textual information or/and low level descriptors. In most cases, images and videos are associated with noisy and incomplete ...

  • 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 ...

  • 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 ...

  • Content based MRSI image indexing and retrieval involving a fuzzy descriptor 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis; Karras, D. A.; Mertzios, B. G. (Institute of Electrical and Electronics Engineers (IEEE), United States, 2010)
    Magnetic resonance spectroscopic imaging (MRSI) integrates both spectroscopic and imaging methods to produce spatially localized spectra from within the sample or patient. Although MRSI is a relatively new imaging technology ...

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

    Chatzichristofis, Savvas A.; Boutalis, Yiannis (Springer Nature, 2009)
    The rapid advances made in the field of radiology, the increased frequency in which oncological diseases appear, as well as the demand for prevailing medical checks, led to the creation of a large database of radiology ...

  • Distributed Multi-Robot Coverage using Micro Aerial Vehicles 

    Renzaglia, A.; Doitsidis, L.; Chatzichristofis, Savvas A.; Martinelli, A.; Kosmatopoulos, E. B. (IEEE (Computer Society), 2013)
    In this paper we present a solution to the problem of positioning a team of Micro Aerial Vehicles for a surveillance task in an environment of arbitrary and unknown morphology. The problem is addressed taking into account ...

  • 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, ...

  • FCTH: Fuzzy color and texture histogram. A low level feature for accurate image retrieval 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis (IEEE (Institute of Electrical and Electronics Engineers , United States), 2008)
    This paper deals with the extraction of a new low level feature that combines, in one histogram, color and texture information. This feature is named FCTH - Fuzzy Color and Texture Histogram - and results from the combination ...

  • 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 ...

  • Golden Retriever - A Java Based Open Source Image Retrieval Engine 

    Tsochatzidis, Lazaros T.; Iakovidou, Chrysanthi; Chatzichristofis, Savvas A.; Boutalis, Yiannis (ACM, 2013)
    Golden Retriever Image Retrieval Engine (GRire) is an open source light weight Java library developed for Content Based Image Retrieval (CBIR) tasks, employing the Bag of Visual Words (BOVW) model. It provides a complete ...

  • Hybrid scheme for fast and accurate image retrieval based on color descriptors 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis (ACTA Press, Canada, 2007)
    This paper proposes a new image retrieval system, thatuses only color features and it's based on a hybrid scheme which combines crisp and fuzzy techniques, in order to retrieve color based similar images. The system ...

  • Identification and Retrieval of DNA Genomes Using Binary Image Representations Produced by Cellular Automata 

    Konstantinidis, K.; Amanatiadis, A.; Chatzichristofis, Savvas A.; Sandaltzopoulos, R.; Sirakoulis, G. Ch. (IEEE (Computer Society), 2014)
    We have developed a novel method for the identification and retrieval of DNA sequences which are represented as binary images. This type of representation emanates from the evolution of one-dimensional nucleotide arrays ...

  • img(Anaktisi): A Web Content Based Image Retrieval System 

    Zagoris, Konstantinos; Chatzichristofis, Savvas A. (IEEE, 2009)
    img(Anaktisi) is a C#/.NET content base image retrieval application suitable for the web. It provides efficient retrieval services for various image databases using as a query a sample image, an image sketched by the ...

  • Img(Rummager): An Interactive Content Based Image Retrieval System 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis; Lux, Mathias (IEEE (Institute of Electrical and Electronics Engineers , United States), 2009)
    This paper presents an image retrieval suite called img(Rummager) which brings into effect a number of new as well as state of the art descriptors. The application can execute an image search based on a query image, either ...

  • Late fusion of compact composite descriptors for retrieval from heterogeneous image databases 

    Chatzichristofis, Savvas A.; Arampatzis, Avi (Association for Computing Machinery (ACM), United States, 2010)
    Compact composite descriptors (CCDs) are global image features, capturing more than one types of information at the same time in a very compact representation. Their quality has so far been evaluated in retrieval from ...