Images may be blurred due to diffusion. This paper investigates the inverse diffusion algorithms for restoration of such images. The conventional One Shoot(OS) algorithm and the Successive Recursion (SR) algorithm are analysed

their performance are compared

and the limits to their validity scopes are revealed and formulated in terms of the blur scales; all these lead to propose a novel "Search and One Shoot" (SOS) algorithm

where the unknown blur scale of a diffused image is detected in a successive approximation manner and the inverse diffusion computing is accomplished in One Shoot with an as small accumulative error as possible. Then

both natural and artificial blurred images are used for tests on the restoration algorithms

including their sensitivity to blur scales of images

their validity scopes

and the effects of SOS algorithm applied to blurred images of incoherent textural structure or scene depth

etc.The experimental results provides evidence that the digital image restoration using inverse diffusion technique can make images of high clarity in scene depth that is beyond the capability of common optical` photographic techniques.