4.3. REAL IMAGE RECOVERY SYSTEMS

In section 4.1 were formulated the conditions necessary for accurate image recovery. From the original image, you need to take samples with a frequency twice the highest spatial frequency of its spectrum. In addition, the recovery filter (or equivalent interpolator) must be calculated so that the main spectrum passes without distortion and completely suppressed all the side spectra when . Below are some considerations about what the results of using non-ideal regenerative filters may be.

In most digital image processing systems, electrical signals, which are image samples, are received from the output of the computer sequentially, according to the usual scanning pattern. These “electrical readings” should be submitted to a playback device (synthesis) of continuous images, for example, a cathode ray tube (CRT) or photo recorder. Below are three ways to perform such an operation.