Image restoration is the process of restoring the original image which has been degraded due to various factors. It means to eliminate or take out the defects of image and brings a clear and clean image. The images can be degraded because of blur, motion, noise and camera misfocus. In other words, the removal of these defects to get the original image is known as image restoration. It is found quite easy to remove the defects of blur and motion by coming up with a very good estimate of the actual blurring function and undo the blur to get the original image. But in cases when the image is blurred by noise factor, the best way to do is to compensate for the degradation it caused. There are number of methods under the degradation model employed in image processing to restore the image like inverse filter, weiner filtering, wavelet restoration and blind deconvolution. Inverse filtering is used to restore image degraded due to blur factor and inverse filtering to restore images degraded by atmospheric turbulence. Hence all the techniques are used for particular purposes.