Colour image coding with wavelets and matching pursuit

  • Ryszard Maciol

    Student thesis: Doctoral ThesisDoctor of Philosophy


    This thesis considers sparse approximation of still images as the basis of a lossy compression system. The Matching Pursuit (MP) algorithm is presented as a method particularly suited for application in lossy scalable image coding. Its multichannel extension, capable of exploiting inter-channel correlations, is found to be an efficient way to represent colour data in RGB colour space. Known problems with MP, high computational complexity of encoding and dictionary design, are tackled by finding an appropriate partitioning of an image. The idea of performing MP in the spatio-frequency domain after transform such
    as Discrete Wavelet Transform (DWT) is explored. The main challenge, though, is to
    encode the image representation obtained after MP into a bit-stream. Novel approaches
    for encoding the atomic decomposition of a signal and colour amplitudes quantisation are
    proposed and evaluated. The image codec that has been built is capable of competing
    with scalable coders such as JPEG 2000 and SPIHT in terms of compression ratio.
    Date of Award2013
    Original languageEnglish
    SupervisorIan T. Nabney (Supervisor)


    • matching pursuit
    • sparse approximations
    • lossy compression
    • colour image coding
    • wavelets
    • run length encoding

    Cite this