M. Pagola

Universidad Pública de Navarra, Pamplona, Navarre, Spain

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Publications (9)9.5 Total impact

  • Article: Image Magnification Using Interval Information
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    ABSTRACT: In this paper, a simple and effective image-magnification algorithm based on intervals is proposed. A low-resolution image is magnified to form a high-resolution image using a block-expanding method. Our proposed method associates each pixel with an interval obtained by a weighted aggregation of the pixels in its neighborhood. From the interval and with a linear K <sub>α</sub> operator, we obtain the magnified image. Experimental results show that our algorithm provides a magnified image with better quality (peak signal-to-noise ratio) than several existing methods.
    IEEE Transactions on Image Processing 12/2011; · 3.04 Impact Factor
  • Article: Image magnification using interval information.
    [show abstract] [hide abstract]
    ABSTRACT: In this paper, a simple and effective image-magnification algorithm based on intervals is proposed. A low-resolution image is magnified to form a high-resolution image using a block-expanding method. Our proposed method associates each pixel with an interval obtained by a weighted aggregation of the pixels in its neighborhood. From the interval and with a linear K(α) operator, we obtain the magnified image. Experimental results show that our algorithm provides a magnified image with better quality (peak signal-to-noise ratio) than several existing methods.
    IEEE Transactions on Image Processing 05/2011; 20(11):3112-23. · 3.04 Impact Factor
  • Chapter: A Method for Constructing V. Young’s Fuzzy Subsethood Measures and Fuzzy Entropies
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    ABSTRACT: In the first part of the chapter we show the three most important axiomatizations of the concept of subsethood measure. Then we present the reasons why we focus on the definition given by V. Young. Next we study a method for constructing said measures and we analyze the conditions in which they satisfy the axioms of Sinha and Dougherty. Afterwards we study the way of obtaining fuzzy entropies that fulfill the valuation property from said subsethood measures.
    09/2008: pages 123-138;
  • Conference Proceeding: Laws for conjunctions and disjunctions in interval type 2 fuzzy sets
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    ABSTRACT: In this paper we study in depth certain properties of interval type 2 fuzzy sets. In particular we recall a method to construct different interval type 2 fuzzy connectives starting from an operator. We further study the law of contradiction and the law of excluded middle for these sets. Furthermore we analyze the properties: idempotency, absorption, and distributiveness.
    Fuzzy Systems, 2008. FUZZ-IEEE 2008. (IEEE World Congress on Computational Intelligence). IEEE International Conference on; 07/2008
  • Article: Generation of interval‐valued fuzzy and atanassov's intuitionistic fuzzy connectives from fuzzy connectives and from Kα operators: Laws for conjunctions and disjunctions, amplitude
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    ABSTRACT: In this paper, we study in-depth certain properties of interval-valued fuzzy sets and Atanassov's intuitionistic fuzzy sets (A-IFSs). In particular, we study the manner in which to construct different interval-valued fuzzy connectives (or Atanassov's intuitionistic fuzzy connectives) starting from an operator. We further study the law of contradiction and the law of excluded middle for these sets. Furthermore, we analyze the following properties: idempotency, absorption, and distributiveness. We conclude relating idempotency with the capacity that some of the connectives studied have for maintaining, in certain conditions, the amplitude (or Atanassov's intuitionistic index) of the intervals on which they act. © 2008 Wiley Periodicals, Inc.
    International Journal of Intelligent Systems 05/2008; 23(6):680 - 714. · 1.65 Impact Factor
  • Conference Proceeding: Construction of Interval Type 2 Fuzzy Images to Represent Images in Grayscale. False Edges
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    ABSTRACT: In this paper we present a method for constructing a special case of interval type 2 fuzzy sets from a grayscale image. We use properties that are exclusive of these sets in order to represent the changes in intensity in the image and so create what in image processing is known as false edges.
    Fuzzy Systems Conference, 2007. FUZZ-IEEE 2007. IEEE International; 08/2007
  • Article: Semiautoduality in a restricted family of aggregation operators
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    ABSTRACT: In this paper we consider aggregation operators satisfying non-decreasingness and some specific boundary conditions. We then analyze some properties of such a family of aggregation operators, introducing the semiautoduality condition, which is weaker than the standard autoduality condition (i.e., the standard self De Morgan identity). Particular families of aggregation operators will appear depending on the context.
    Fuzzy Sets and Systems 01/2007; 158(12):1360-1377. · 1.76 Impact Factor
  • Article: Contrast of a fuzzy relation
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    ABSTRACT: In this paper we address a key problem in many fields: how a structured data set can be analyzed in order to take into account the neighborhood of each individual datum. We propose representing the dataset as a fuzzy relation, associating a membership degree with each element of the relation. We then introduce the concept of interval-contrast, a means of aggregating information contained in the immediate neighborhood of each element of the fuzzy relation. The interval-contrast measures the range of membership degrees present in each neighborhood. We use interval-contrasts to define the necessary properties of a contrast measure, construct several different local contrast and total contrast measures that satisfy these properties, and compare our expressions to other definitions of contrast appearing in the literature. Our theoretical results can be applied to several different fields. In an Appendix A, we apply our contrast expressions to photographic images.
    Information Sciences. 180(8):1326-1344.
  • Article: Relationship between restricted dissimilarity functions, restricted equivalence functions and normal EN-functions: Image thresholding invariant
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    ABSTRACT: In this paper, we present the definition of restricted dissimilarity function. This definition arises from the concepts of dissimilarity and equivalence function. We analyze the relation there is between restricted dissimilarity functions, restricted equivalence functions (see [Bustince, H., Barrenechea, E., Pagola, M., 2006. Restricted equivalence functions. Fuzzy Sets Syst. 157, 2333–2346]) and normal EN-functions. We present characterization theorems from implication operators and automorphisms. Next, by aggregating restricted dissimilarity functions in a special way, we construct distance measures of Liu, proximity measures of Fan et al. and fuzzy entropies. We also study diverse interrelations between the above-mentioned concepts. These interrelations enable us to prove that under certain conditions, the threshold of an image calculated with the algorithm of Huang and Wang [Huang, L.K., Wang, M.J., 1995. Image thresholding by minimizing the measure of fuzziness. Pattern Recognit. 28 (1), 41–51], with the methods of Forero [Forero, M.G., 2003. Fuzzy thresholding and histogram analysis. In: Nachtegael, M., Van der Weken, D., Van de Ville, D., Kerre, E.E. (Eds.), Fuzzy Filters for Image Processing. Springer, pp. 129–152] or with the algorithms developed in [Bustince, H., Barrenechea, E., Pagola, M., 2007. Image thresholding using restricted equivalence functions and maximizing the measures of similarity. Fuzzy Sets Syst. 158, 496–516] is always the same, that is, it remains invariant.
    Pattern Recognition Letters.