Computation of two N-point IDCT s via a single N-point IFFT using radix-4 algorithm & its proposed architecture

Abstract

This paper addresses the problem of the evaluation of inverse discrete cosine transform (IDCT) using existing radix-2 IFFT algorithm applicable for image and signal processing where a huge number of data points are required for a particular operation. Since radix-4 architecture has fewer multiplications than radix-2, then it is judicial to carry out the IDCT operation via radix-4 IFFT for a huge savings of number of computations for the data points which are power of four. In this paper the authors have modified the existing IDCT-DFT algorithm to allow the computation of two concurrent N Point IDCT s via a single N point radix-4 IFFT instead of using radix-2 IFFT. As a result the total amount of arithmetic workload is greatly reduced. A supporting architecture which can be applicable for real time operation is also suggested to realize a 16 point IDCT algorithm.