The quality control by visual perception maybe done by processing the information obtained from a TV camera by mean of a computer. In the most simple cases, the computer can by substituted by a microcomputer and a specialized interface. This paper shows the electronic devic for video signal codification and preprocessing, which allows to give a very reduced information to the microcomputer. This feature lets perform the control algorithm in a real time. This interface is not general purpose for all applications. It is useful only in some cases, classifying objects not very complex. Finally the results obtained from the application of the systems to the corks quality control are presented.