83 research outputs found

    Information-Theoretic Multiclass Classification Based on Binary Classifiers: On Coding Matrix Design, Reliability and Maximum Number of Classes

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    In this paper, we consider the multiclass classification problem based on sets of independent binary classifiers. Each binary classifier represents the output of a quantized projection of training data onto a randomly generated orthonormal basis vector thus producing a binary label. The ensemble of all binary labels forms an analogue of a coding matrix. The properties of such kind of matrices and their impact on the maximum number of uniquely distinguishable classes are analyzed in this paper from an information-theoretic point of view. We also consider a concept of reliability for such kind of coding matrix generation that can be an alternative to other adaptive training techniques and investigate the impact on the bit error probability. We demonstrate that it is equivalent to the considered random coding matrix without any bit reliability information in terms of recognition rat

    Towards geometrically robust data-hiding with structured codebooks

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    In this paper we analyze performance of practical robust data-hiding in channels with geometrical transformations. By applying information-theoretic argument we show that performance of a system designed based on both random coding and random binning principles is bounded by the same maximal achievable rate for the cases when communication channel includes geometrical transformations or not. Targeting to provide theoretic performance limits of practical robust data-hiding we model it using a multiple access channel (MAC) with side information (SI) available at one of encoders and present the bounds on achievable rates of reliable communications to such a protocol. Finally, considering template-based and redundant-based design of geometrically robust data-hiding systems, we perform security analysis of their performance and present results in terms of number of trial efforts the attacker needs to completely remove hidden informatio

    Generalized radar/radiometry imaging problems, Journal of Telecommunications and Information Technology, 2001, nr 4

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    In the paper the results of spatio-temporal imaging simulation based on radar, synthetic aperture radar (SAR) and radiometry systems are presented. The analytical relationship between object scattering/emitting and the formed image is given and the general approach for the description of imaging system by means of Frendholm equation solution is developed. The potential limit of image resolution based on Rao-Cramer inequality is estimated

    ROBUST IMAGE RESTORATION BASED ON M-ESTIMATION CONCEPT AND PARAMETRIC MODEL OF IMAGE SPECTRUM

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    Abstract: The paper presents robust approach to image restoration problem that combines the properties of classical regularized iterative algorithms and robust features based on the concept of M-estimators. The proposed approach makes possible to suppress the influence of impulse noise on restoration process. To enhance the convergence rate of iterations, remove ringing effect and preserve edges and fine details in the restored image the parametric constrain on amplitude image spectrum is used that bounds from below the energy of the restored image at high frequencies opposite regularization. The robustness of the proposed algorithm is demonstrated. Key words: image restoration, robust estimation, regularization, iterative algorithm. 1

    In Pursuit of an Optimum Optical Imaging Technology for Early Detection of Dental Caries

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    Clinical caries detection techniques, such as radiographs, are not sensitive to detect and monitor the progression of caries at early stages. In recent years, several optics-based imaging modalities have been proposed for early detection of caries. In this thesis, we report on a systemic comparative study on the performances of optical coherence tomography and thermophotonic lock-in imaging (TPLI) as early caries detection imaging modalities based on light scattering and absorption, respectively. Through controlled demineralization on extracted human teeth, our results suggest that TPLI provides better sensitivity and detection threshold in detecting early stages of caries. The outcome justifies the need for a light-absorption based imaging modality to produce depth-resolved images. Therefore, preliminary imaging studies on a 3-D imaging platform known as a Truncated-Correlation Photothermal Coherence Tomography (TC-PCT) system was conducted to achieve optimal diagnostic yield. The results demonstrate that TC-PCT can detect early caries with significant enhancement in depth-resolution

    Information-theoretic data-hiding: Recent achievements and open problems

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    In this paper we introduce and develop a framework for visual data-hiding technologies that aim at resolving emerging problems of modern multimedia networking. First, we introduce the main open issues of public network security, quality of services control and secure communications. Secondly, we formulate digital data-hiding into visual content as communications with side information and advocate an appropriate informationtheoretic framework for the analysis of different data-hiding methods in various applications. In particular, Gel’fand-Pinsker channel coding with side information at the encoder and Wyner-Ziv source coding with side information at the decoder are used for this purpose. Finally, we demonstrate the possible extensions of this theory for watermark-assisted multimedia processing and indicate its perspectives for distributed communications. Keywords: Data-hiding; robust watermarking; copyright protection; tamper proofing; secure communications; steganography; network security; network quality-of-service. 1

    Outline

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    2. Watermarking as Communication with Side Information 3. Adaptive diversity watermarking 4. Affine transform
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