Efficient VLSI Architecture for 16-Point Discrete Cosine Transform

The Discrete Cosine Transform (DCT) is an important transform in image and video processing systems. The perception of human visualization permits us to be numerically approximate rather than exact with slight compromise in accuracy. In this paper, we have proposed a digital implementation of 16-point approximate DCT architecture based on Modified Gate Diffusion Input (MGDI) technique. The 8-point DCT architecture can be realized in digital Very Large Scale Integration (VLSI) hardware with only 12 additions. The proposed 8-transistor MGDI full adder is used instead of existing 10-transistor MGDI full adder in the DCT architecture. It results in reduced circuit complexity, power and delay. Approximate multiplier-free MGDI DCT is simulated in Tanner SPICE for 90-nm CMOS process technology at 100 MHz. The simulation result shows that 20%, 16% and 7% of area, power and delay are reduced, respectively, when compared with approximate DCT by using 14 additions. The performance was evaluated based on peak signal-to-noise ratio (PSNR), and the proposed architecture shows enhancement in terms of hardware complexity, regularity and modularity with a little compromise in accuracy.