Digital images are everywhere: consumer, business, industrial, medical, military, scientific. However, the original raw data coming from the acquisition device is often of poor quality because of distortions such as noise, blurring, quantization, geometrical aberrations, etc.
To obtain an image of acceptable quality some processing is necessary to suppress these degradations.

Such processing is called signal restoration/reconstruction.

Restoration is even more important if we consider that, before they reach the end-user, the majority of images undergoes some further processing (resampling, equalization, compression, enhancement) that cannot be directly performed on distorted data.