Motion analysis in 3D DCT domain and its application to video coding

• Published in: Signal processing. Image communication Vol. 20; no. 6; pp. 510 - 528
• Main Authors: Božinović, Nikola, Konrad, Janusz
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2005; Elsevier
• Subjects: 3D transform coding; Applied sciences; Coding, codes; Coefficient quantization; Coefficient scanning; DCT; Discrete cosine transform; Exact sciences and technology; Image processing; Information, signal and communications theory; Motion analysis; Sampling, quantization; Signal and communications theory; Signal processing; Telecommunications and information theory; Video coding; Video coding; Coefficient scanning; DCT; Coefficient quantization; 3D transform coding; Motion analysis; Discrete cosine transform; Performance evaluation; Signal compression; Fourier transformation; Image processing; Data compression; Adaptive method; Video signal processing; Block matching; Image coding; Energy characteristic; Signal quantization; Image sequence; Motion detection; Discrete cosine transforms; Spectral method; Motion estimation; Entropy codes; Image compression; Translation motion; Transform coding; Signal processing
• ISSN: 0923-5965; 1879-2677
• DOI: 10.1016/j.image.2005.03.007

Global, constant-velocity, translational motion in an image sequence induces a characteristic energy footprint in the Fourier-transform (FT) domain; spectrum is limited to a plane with orientation defined by the direction of motion. By detecting these spectral occupancy planes, methods have been proposed to estimate such global motion. Since the discrete cosine transform (DCT) is a ubiquitous tool of all video compression standards to date, we investigate in this paper properties of motion in the DCT domain. We show that global, constant-velocity, translational motion in an image sequence induces in the DCT domain spectral occupancy planes, similarly to the FT domain. Unlike in the FT case, however, these planes are subject to spectral folding. Based on this analysis, we propose a motion estimation method in the DCT domain, and we show that results comparable to standard block matching can be obtained. Moreover, by realizing that significant energy in the DCT domain concentrates around a folded plane, we propose a new approach to video compression. The approach is based on 3D DCT applied to a group of frames, followed by motion-adaptive scanning of DCT coefficients (akin to “zig-zag” scanning in MPEG coders), their adaptive quantization, and final entropy coding. We discuss the design of the complete 3D DCT coder and we carry out a performance comparison of the new coder with ubiquitous hybrid coders.