We describe the point spread function (PSF) as
h(m,n), which is the 2D impulse response produced from
a point source of light passing through the degradation
system in the absence of noise. Although we have the
method to estimate the PSF’s (such as defocus, camera
shaking, object motion, etc.), in practical forensic image
restoration, it is not easy for us to obtain the exact parameters
of PSF’s. That is because the real degradation
may come from several PSF’s simultaneously. What we
often do is to choose one or several “proper” PSF models
from what we have so far. Those PSF’s include 1-D
motion blur, uniform 2-D motion blur, Gaussian blur,atmospheric turbulence blur, and uniform out-of-focus
blur [1,10]. We summarize them as follows: