13.1 INTRODUCTION

Multidimensional digital filters are used in several areas of digital signal processing. Two-dimensional (2-D) digital filters are used for image processing applications such as image enhancement and noise removal. Three-dimensional (3-D) digital filters are used to process consecutive frames of images such as video data and medical imaging, such as computerized tomography (CT) and magnetic resonance imaging (MRI) scans. Another interesting example of 3-D filters is velocity filters. Velocity filters can be used to detect the speed of an object in a video sequence. Velocity filters are used also in the processing of seismic data sets or signal streams from microphone arrays to separate different signal components.