Now showing items 1-19 of 19

  • Adaptive Digital Image Watermarking Based on Combination of HVS Models 

    Foris, P.; Levicky, D. (Společnost pro radioelektronické inženýrství, 2009-09)
    In this paper two new blind adaptive digital watermarking methods of color images are presented. The adaptability is based on perceptual watermarking which exploits Human Visual System (HVS) models. The first method performs ...
  • Adaptive Goertzel's Algorithm for DFT Computation with Higher Accuracy 

    Levicky, D.; Drutarovsky, M.; Galajda, P.; Kocur, D.; Marchevsky, S. (Společnost pro radioelektronické inženýrství, 1996-04)
    In this paper the adaptive Goertzel's algorithm applied for required DFT coefficient computation in the harmonic analyser is described. This algorithm utilizes effective combination of the synchronous DFT and window method. ...
  • Artificial Neural Network for Displacement Vectors Determination 

    Levicky, D.; Bohmann, P. (Společnost pro radioelektronické inženýrství, 1997-09)
    An artificial neural network (NN) for displacement vectors (DV) determination is presented in this paper. DV are computed in areas which are essential for image analysis and computer vision, in areas where are edges, lines, ...
  • Codebook Code Division Multiple Access Image Steganography 

    Levicky, D.; Surin, S. (Společnost pro radioelektronické inženýrství, 2005-04)
    In this paper, a new modification of spread spectrum image steganography (SSIS) is presented. The proposed modification of SSIS hides and recovers a message of substantial length within digital image while maintaining the ...
  • Digital Image Watermaking in Color Models Using DCT Transformation 

    Hovancak, R.; Levicky, D. (Společnost pro radioelektronické inženýrství, 2004-04)
    In recent years, an access to multimedia data has become much easier due to the rapid growth of the Internet. While this is usually considered an improvement of everyday life, it also makes unauthorized copying and ...
  • Digital Watermarking in Wavelet Transform Domain 

    Candik, M.; Matus, E.; Levicky, D. (Společnost pro radioelektronické inženýrství, 2001-06)
    This paper presents a technique for the digital watermarking of still images based on the wavelet transform. The watermark (binary image) is embedded into original image in its wavelet domain. The original unmarked image ...
  • Fractal Image Coding with Digital Watermarks 

    Candik, M.; Levicky, D.; Klenovicova, Z. (Společnost pro radioelektronické inženýrství, 2000-12)
    In this paper are presented some results of implementation of digital watermarking methods into image coding based on fractal principles. The paper focuses on two possible approaches of embedding digital watermarks into ...
  • Human Visual System Models in Digital Image Watermarking 

    Levicky, D.; Foris, P. (Společnost pro radioelektronické inženýrství, 2004-12)
    In this paper some Human Visual System (HVS) models used in digital image watermarking are presented. Four different HVS models, which exploit various properties of human eye, are described. Two of them operate in transform ...
  • Hybrid Coding of Image Sequences by Using Wavelet Transform 

    Levicky, D.; Petrulak, P.; Radoczi, P.; Surin, M. (Společnost pro radioelektronické inženýrství, 2000-04)
    In this paper, a new method of hybrid coding of image sequences by using wavelet transform is proposed. The basic MPEG scheme with DCT has been modificated in sense of replacement DCT by wavelet transform. In the proposed ...
  • Implementations of HVS Models in Digital Image Watermarking 

    Foris, P.; Levicky, D. (Společnost pro radioelektronické inženýrství, 2007-04)
    In the paper two possible implementations of Human Visual System (HVS) models in digital watermarking of still images are presented. The first method performs watermark embedding in transform domain of Discrete Cosine ...
  • Interactive Progressive Image Transmission 

    Matus, E.; Levicky, D. (Společnost pro radioelektronické inženýrství, 1999-06)
    In progressive image transmission (PIT) the image is transmitted progressively i.e. the low detail image is transmitted as first followed by transmission of detail signals. In our contribution we consider interactivity in ...
  • A novel JPEG steganography method based on modulus function with histogram analysis 

    Banoci, V.; Bugar, G.; Levicky, D.; Klenovicova, Z. (Společnost pro radioelektronické inženýrství, 2012-06)
    In this paper, we present a novel steganographic method for embedding of secret data in still grayscale JPEG image. In order to provide large capacity of the proposed method while maintaining good visual quality of ...
  • Pixel Decimation in Block Matching Techniques 

    Radoczi, P.; Levicky, D. (Společnost pro radioelektronické inženýrství, 2000-12)
    Block motion estimation using full search algorithm is computationally extensive. Previously proposed fast algorithms reduce the computation cost by limiting the number of locations searched. In this paper we present ...
  • Progressive Image Reconstruction Using Morphological Skeleton 

    Levicky, D.; Chromek, P. (Společnost pro radioelektronické inženýrství, 1992-5)
    This paper presents the results of a study on use of morphological skeleton to represent, progressive transmission and reconstruction of binary images. For images containing blobs and large areas, the skeleton subsets are ...
  • Robust Digital Watermarking Based on the Log-Polar Mapping 

    Ridzon, R.; Levicky, D. (Společnost pro radioelektronické inženýrství, 2007-12)
    The geometrical attacks are still an open problem for many digital watermarking algorithms used in present time. Most of geometrical attacks can be described by using affine transforms. This article deals with digital ...
  • Some Modifications of Fractal Image Coding 

    Levicky, D.; Candik, M.; Pundzak, R. (Společnost pro radioelektronické inženýrství, 1999-09)
    In this paper some modifications of fractal image coding are presented. Proposed methods are based on correlation coefficients computing as an alternative approach to searching of similarity between blocks. The convergence ...
  • A Two Layer Hybrid Image Coder 

    Levicky, D.; Matus, E.; Kral, P. (Společnost pro radioelektronické inženýrství, 1995-04)
    This paper presents a new idea of a two layer hybrid image coder based on visual pattern image coding of original image and residual image by means of the wavelet transform. At first contours are extracted from the original ...
  • Universal Image Steganalytic Method 

    Banoci, V.; Broda, M.; Bugar, G.; Levicky, D. (Společnost pro radioelektronické inženýrství, 2014-12)
    In the paper we introduce a new universal steganalytic method in JPEG file format that is detecting well-known and also newly developed steganographic methods. The steganalytic model is trained by MHF-DZ steganographic ...
  • Using of Hand Geometry in Biometric Security Systems 

    Varchol, P.; Levicky, D. (Společnost pro radioelektronické inženýrství, 2007-12)
    In this paper, biometric security system for access control based on hand geometry is presented. Biometric technologies are becoming the foundation of an extensive array of highly secure identification and personal ...