Marking and detection of text documents using transform-domain techniques

Yong Liu, Jonathon Mant, Edward Wong, Steven Low

    Research output: Contribution to journalConference articlepeer-review


    We investigate the use of frequency domain techniques to watermark text documents. A text image is essentially binary and hence contains large high-frequency components. This has several implications on the obtrusiveness and detection performance of frequency domain marking of text images, as illustrated by our extensive experiments. Generally marking is more obtrusive on a text than pictorial image. It almost always creates a 'dirty' background. 'Cleaning' the background by thresholding light greys to white renders the watermark less obtrusive but also sharply reduces the detector response, making it unrobust against noise. Both text and pictorial images seem very susceptible to shifting; this contrasts with extreme robustness against shifting of spatial domain marking through line or word shifting. Finally, we explore the combination of spatial domain marking and frequency domain detection and present preliminary experimental results on the combined approach.

    Original languageEnglish (US)
    Pages (from-to)317-328
    Number of pages12
    JournalProceedings of SPIE - The International Society for Optical Engineering
    StatePublished - 1999
    EventProceedings of the 1999 Security and Watermarking of Multimedia Contents - San Jose, CA, USA
    Duration: Jan 25 1999Jan 27 1999

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Computer Science Applications
    • Applied Mathematics
    • Electrical and Electronic Engineering


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