Title :
Identification of image and blur parameters in frequency domain using the EM algorithm
Author :
Anarim, Emin ; Ucar, H. ; Istefanopulos, Yorgo
Author_Institution :
Dept. of Electr. & Electron. Eng., Bogazici Univ., Istanbul, Turkey
fDate :
1/1/1996 12:00:00 AM
Abstract :
We extend a method presented previously, which considers the problem of the semicausal autoregressive (AR) parameter identification for images degraded by observation noise only. We propose a new approach to identify both the causal and semicausal AR parameters and blur parameters without a priori knowledge of the observation noise power and the PSF of the degradation. We decompose the image into 1-D independent complex scalar subsystems resulting from the vector state-space model by using the unitary discrete Fourier transform (DFT). Then, by applying the expectation-maximization (EM) algorithm to each subsystem, we identify the AR model and blur parameters of the transformed image. The AR parameters of the original image are then identified by using the least squares (LS) method. The restored image is obtained as a byproduct of the EM algorithm
Keywords :
autoregressive processes; discrete Fourier transforms; frequency-domain analysis; image restoration; least squares approximations; noise; parameter estimation; state-space methods; 1D independent complex scalar subsystems; DFT; EM algorithm; PSF; blur parameters; causal AR parameters; expectation-maximization algorithm; frequency domain; image identification; image parameters; image restoration; least squares method; observation noise; observation noise power; semicausal autoregressive parameter identification; transformed image; unitary discrete Fourier transform; vector state-space model; Degradation; Discrete Fourier transforms; Equations; Frequency domain analysis; Image representation; Image restoration; Least squares methods; Parameter estimation; Power system modeling; Statistics;
Journal_Title :
Image Processing, IEEE Transactions on