DCT approximations based on Chen’s factorization

• Published in: Signal processing. Image communication Vol. 58; pp. 14 - 23
• Main Authors: Tablada, C.J., da Silveira, T.L.T., Cintra, R.J., Bayer, F.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-10-2017; Elsevier BV
• Subjects: Algorithms; Approximate DCT; Approximation; Chen’s factorization; Coding; Complexity; Digital imaging; Experiments; Factorization; Fast algorithms; Image and video compression; Image compression; JPEG encoders-decoders; Low-complexity transforms; Transformations; Video compression; Image and video compression; Low-complexity transforms; Chen’s factorization; Approximate DCT; Fast algorithms
• ISSN: 0923-5965; 1879-2677
• DOI: 10.1016/j.image.2017.06.014

In this paper, two 8-point multiplication-free DCT approximations based on the Chen’s factorization are proposed and their fast algorithms are also derived. Both transformations are assessed in terms of computational cost, error energy, and coding gain. Experiments with a JPEG-like image compression scheme are performed and results are compared with competing methods. The proposed low-complexity transforms are scaled according to Jridi–Alfalou–Meher algorithm to effect 16- and 32-point approximations. The new sets of transformations are embedded into an HEVC reference software to provide a fully HEVC-compliant video coding scheme. We show that approximate transforms can outperform traditional transforms and state-of-the-art methods at a very low complexity cost.
•We propose two 8-point multiplication-free DCT approximations.•We consider a scaled algorithm to propose 16- and 32-point low complexity transforms.•We measure the quality of the proposed transforms compared with competing methods.•Still JPEG-like image and video compression experiments were performed.•Introduced transforms were embedded into an HEVC reference software.