ABSTRACT
Digital image processing is a very important field by itself that has been treated in many textbooks. This chapter discusses the general procedures used in the digital processing of images, which is performed by means of a window or mask, represented by a matrix of N × N pixels. The simplest operation is detection of a pixel with a gray level that varies too greatly from the surrounding pixels. In the median filter, the value to be inserted at the center of the kernel is not the average value of the surrounding pixels; instead, the median value of these pixels is taken. The square filter just described is not the ideal because it leaves some high frequencies unfiltered due to the secondary maxima in the spectrum of the sinc function. Some frame grabbers have enough memory to store several original frames as well as frames resulting from processing other frames.
