  We investigate the effects of the regularization parameter for the norm ()
and penalty parameter () in the alternating direction method of multipliers
(ADMM) on the quality of restored medical images. Simulation studies are
performed using images degraded by a point spread function (PSF) and Gaussian
noise. The j-th column of the system matrix () is calculated by convolving the
image with unity at pixel j and zero at all other pixels and the PSF. The
simulation studies show that the mean structural similarity index is maximal
when is approximately 10 to 20, where , with and being the transpose of A and
the observed data, respectively. The restored image became blurred with a
decrease in . This study will be useful for identifying optimal parameter
values in the ADMM when applied to medical image restoration.
