Digital Video Processing for Engineers

4

Introduction to Digital Filtering

Chapter Outline

4.1 Median Filtering

4.2 FIR Filters

4.3 FIR Filter Construction

4.4 Computing Frequency Response

Digital filtering is used in different aspects of video signal processing. One application is reducing random noise effects or corrupted pixels in images or video. Finite Impulse Response (FIR) filters can be used to smooth out an image, and to reduce random noise, but the drawback is that it will soften or blur sharp edges in the image.

4.1 Median Filtering

Another type of filter often better suited to reducing noise in an image is the median filter. A median filter is a non-linear filter, which does not use multipliers. It analyzes the image pixel by pixel, and replaces each pixel with the median ...