Down-sampling design in DCT domain with arbitrary ratio for image/video transcoding

  • Authors:

  • Xiang Yu;En-hui Yang;Haiquan Wang

  • Affiliations:

  • Research In Motion/Slip Stream and Department of Electrical and Computer Engineering, University of Waterloo and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo ...;Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario, Canada;College of Communication Engineering, Hangzhou Dianzi University, Xiasha, Hangzhou, China and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario, ON, Cana ...

  • Venue:
  • IEEE Transactions on Image Processing
  • Year:
  • 2009

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Abstract

This paper proposes a designing framework for down-sampling compressed images/video with arbitrary ratio in the discrete cosine transform (DCT) domain. In this framework, we first derive a set of DCT-domain down-sampling methods which can be represented by a linear transform with double-sided matrix multiplication (LTDS) in the DCT domain and show that the set contains a wide range of methods with various complexity and visual quality. Then, for a preselected spatial-domain down-sampling method, we formulate an optimization problem for finding an LTDS to approximate the given spatial-domain down-sampling method for a trade-off between the visual quality and the complexity. By modeling LTDS as a multiple layer network, a so-called structural learning with forgetting algorithm is then applied to solve the optimization problem. The proposed framework has been applied to discover optimal LTDSs corresponding to a spatial down-sampling method with Butterworth low-pass filtering and bicubic interpolation. Experimental results show that the resulting LTDS achieves a significant reduction on the complexity when compared with other methods in the literature with similar visual quality.