Spectral methods for multimodal data analysis
      
      
        
      
      
      
      
      
      
      
      
      
      
      
      
        153 p
        
        
      
      
      
      
      
      
      
      Thèse de doctorat: Università della Svizzera italiana, 2016
      
      
      
      
      
      
      
       
      
      
      
        
        English
        
        
        
          Spectral methods have proven themselves as an important and versatile tool in a wide range of problems in the fields of computer  graphics, machine learning, pattern recognition, and computer vision, where many important problems boil down to constructing a  Laplacian operator and finding a few of its eigenvalues and eigenfunctions. Classical examples include the computation of diffusion  distances on manifolds in computer graphics, Laplacian eigenmaps, and spectral clustering in machine learning. In many cases,  one has to deal with multiple data spaces simultaneously. For example, clustering multimedia data in machine learning applications  involves various modalities or ``views'' (e.g., text and images), and finding correspondence between shapes in computer graphics  problems is an operation performed between two or more modalities. In this thesis, we develop a generalization of spectral  methods to deal with multiple data spaces and apply them to problems from the domains of computer graphics, machine learning,  and image processing. Our main construction is based on simultaneous diagonalization of Laplacian operators. We present an  efficient numerical technique for computing joint approximate eigenvectors of two or more Laplacians in challenging noisy  scenarios, which also appears to be the first general non-smooth manifold optimization method. Finally, we use the relation  between joint approximate diagonalizability and approximate commutativity of operators to define a structural similarity measure for  images. We use this measure to perform structure-preserving color manipulations of a given image.
        
        
       
      
      
      
        
        
        
        
        
        
        
        
        
        
        
        
        
        
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                  Computer science and technology
                
              
            
          
        
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          https://n2t.net/ark:/12658/srd1318738