2-D FIR Filter Design Using the NDFT

Two-dimensional (2-D) digital filters find applications in diverse areas such as image processing and coding, robotics and computer vision, seismology, sonar, radar and astronomy. In applications such as image processing, preservation of the phase information is important [Huang et al., 1975]. In this respect, FIR filters offer a distinct advantage over IIR filters, since they can easily attain linear-phase or zero-phase characteristics. Besides, they are guaranteed to be stable. In this chapter, we use the 2-D NDFT, defined in Chapter 2 (Section 2.5), to design 2-D FIR filters by nonuniform frequency sampling of the specified frequency response.