Spatial-frequency composite watermarking for digital image copyright protection

Po Chyi Su, C. C.Jay Kuo

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations


Digital watermarks can be classified into two categories according to the embedding and retrieval domain, i.e. spatial- and frequency-domain watermarks. Because the two watermarks have different characteristics and limitations, combination of them can have various interesting properties when applied to different applications. In this research, we examine two spatial-frequency composite watermarking schemes. In both cases, a frequency-domain watermarking technique is applied as a baseline structure in the system. The embedded frequency-domain watermark is robust against filtering and compression. A spatial-domain watermarking scheme is then built to compensate some deficiency of the frequency-domain scheme. The first composite scheme is to embed a robust watermark in images to convey copyright or author information. The frequency-domain watermark contains owner's identification number while the spatial-domain watermark is embedded for image registration to resist cropping attack. The second composite scheme is to embed a fragile watermark for image authentication. The spatial-domain watermark helps in locating the tampered part of the image while the frequency-domain watermark indicates the source of the image and prevents double watermarking attack. Experimental results show that the two watermarks do not interfere with each other and different functionalities can be achieved. Watermarks in both domains are detected without resorting to the original image. Furthermore, the resulting watermarked image can still preserve high fidelity without serious visual degradation.

Original languageEnglish
Pages (from-to)295-305
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2000
EventSecurity and Watermarking of Multimedia Contents II - San Jose, CA, USA
Duration: 24 Jan 200026 Jan 2000


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