Multiplierless 16-point DCT Approximation for Low-complexity Image and Video Coding
This work addresses the need for efficient image and video compression in resource-constrained hardware, though it is incremental as it builds on existing low-complexity transform methods.
The authors introduced a multiplierless 16-point approximate DCT for low-complexity image and video coding, achieving the lowest arithmetic cost of 44 additions and showing 35-37% improvements in VLSI metrics compared to competitors.
An orthogonal 16-point approximate discrete cosine transform (DCT) is introduced. The proposed transform requires neither multiplications nor bit-shifting operations. A fast algorithm based on matrix factorization is introduced, requiring only 44 additions---the lowest arithmetic cost in literature. To assess the introduced transform, computational complexity, similarity with the exact DCT, and coding performance measures are computed. Classical and state-of-the-art 16-point low-complexity transforms were used in a comparative analysis. In the context of image compression, the proposed approximation was evaluated via PSNR and SSIM measurements, attaining the best cost-benefit ratio among the competitors. For video encoding, the proposed approximation was embedded into a HEVC reference software for direct comparison with the original HEVC standard. Physically realized and tested using FPGA hardware, the proposed transform showed 35% and 37% improvements of area-time and area-time-squared VLSI metrics when compared to the best competing transform in the literature.