Noise characterization of computed tomography using the covariance matrix.
    
    
        
    
    
        
        Proc. SPIE 7622:76224Z (2010)
    
    
    
		
		
			
				In order to compare different imaging systems, it is necessary to obtain detailed information about the system noise, its deterministic properties and task specic signal-to-noise ratio (SNR). The current standard method for characterizing noise in CT scanners is based on the pixel standard deviation of the image of a water-equivalent uniform phantom. The Fourier-based noise power spectrum (NPS)improves on the limitations of the pixel standard deviation by accounting for noise correlations. However, it has been shown that the Fourier-methods used to describe the system performance result in systematic errors as they make some limiting assumptions such as shift invariance and wide sense stationarity, which are not satised by real CT systems. For a more general characterization of the imaging system noise, a covariance matrix eigenanalysis can be performed. In this paper we present the experimental methodology for the evaluation of the noise of computed tomography systems. We used a bench-top at-panel-based cone-beam CT scanner and a cylindrical water-lled PMMA phantom. For the 3-dimensional reconstructed volume, we calculated the covariance matrix, its eigenvectors and eigenvalues for the xy-plane as well as for the yz-plane, and compared the results with the NPS. Furthermore, we analyzed the location-specic noise in the images. The evaluation of the noise is a rst step toward determining the task-specic SNR.
			
			
				
			
		 
		
			
				
					
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        Publikationstyp
        Artikel: Journalartikel
    
 
    
        Dokumenttyp
        Wissenschaftlicher Artikel
    
 
    
        Typ der Hochschulschrift
        
    
 
    
    
        Schlagwörter
        computed tomography;covariance matrix;SNR;detectability;noise power spectrum
    
 
    
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        Sprache
        englisch
    
 
    
        Veröffentlichungsjahr
        2010
    
 
    
        Prepublished im Jahr 
        
    
 
    
        HGF-Berichtsjahr
        0
    
 
    
    
        ISSN (print) / ISBN
        0277-786X
    
 
    
        e-ISSN
        1996-756X
    
 
    
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	    Band: 7622,  
	    Heft: PA,  
	    Seiten: ,  
	    Artikelnummer: 76224Z 
	    Supplement: ,  
	
    
 
  
        
            Reihe
            Proceedings of SPIE
        
 
        
            Verlag
            SPIE
        
 
        
            Verlagsort
            Bellingham, WA
        
 
	
        
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        Begutachtungsstatus
        Peer reviewed
    
 
     
    
        POF Topic(s)
        30504 - Mechanisms of Genetic and Environmental Influences on Health and Disease
    
 
    
        Forschungsfeld(er)
        Radiation Sciences
    
 
    
        PSP-Element(e)
        G-503600-002
    
 
    
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        Erfassungsdatum
        2011-01-19