author = "Rangayyan, R. M. and Ferrari, R. J. and Desautels, J. E. L. and 
                         Fr{\`e}re, A. F.",
                title = "Directional analysis of images with Gabor wavelets",
                 year = "2000",
               editor = "Carvalho, Paulo Cezar Pinto and Walter, Marcelo",
                pages = "170--177",
         organization = "Brazilian Symposium on Computer Graphics and Image Processing, 13. 
            publisher = "IEEE Computer Society",
              address = "Los Alamitos",
                 note = "The conference was held in Gramado, RS, Brazil, from October 17 to 
             keywords = "wavelet transforms linear directional component analysis images 
                         multiresolution representation Gabor wavelets Gabor filter 
                         dictionary tuning frequency orientation redundancy reduction 
                         filter responses Karhunen-Loeve transform thresholding principal 
                         components Rose diagrams phase images oriented patterns mammogram 
                         asymmetry feature extraction parametric statistical classifier 
                         distortion cases Mini-MIAS database leave-one-out methodology 
                         diagnostic accuracy.",
             abstract = "The paper presents a new scheme for analysis of linear directional 
                         components in images by using a multiresolution representation 
                         based on Gabor wavelets. A dictionary of Gabor filters with 
                         varying tuning frequency and orientation, specifically designed in 
                         order to reduce the redundancy in the wavelet-based 
                         representation, is applied to the given image. The filter 
                         responses for different scales and orientation are analyzed by 
                         using the Karhunen-Loeve (KL) transform and Otsu's (1979) method 
                         of thresholding. The KL transform is applied to select the 
                         principal components of the filter responses, preserving only the 
                         most relevant directional elements appearing at all scales. The 
                         first N principal components, thresholded by using Otsu's method, 
                         are used to reconstruct the magnitude and phase of the directional 
                         components of the image. Rose diagrams computed from the phase 
                         images are used for quantitative and qualitativeanalysis of the 
                         oriented patterns. The proposed scheme is applied to the analysis 
                         of asymmetry between left and right mammograms. For this purpose, 
                         a set of three features is extracted from the Rose diagrams and 
                         used in a parametric statistical classifier. A total of 80 images 
                         from 20 normal cases, 14 asymmetric cases, and 6 distortion cases 
                         from the Mini-MIAS database were used to evaluate the scheme using 
                         the leave-one-out methodology, resulting in an average diagnostic 
                         accuracy of 72.5%.",
  conference-location = "Gramado, RS, Brazil",
      conference-year = "October",
         organisation = "SBC - Brazilian Computer Society",
           targetfile = "170-177.pdf",
        urlaccessdate = "2020, Nov. 28"