摘要：This paper proposes a digital watermarking technique based on discrete wavelet transformation (DWT) to effectively protect the intellectual property rights of digital images. Basically, the proposed technique uses the DWT frequency coefficients of a digital image to preserve important image features and to embed a meaningful digital watermark into the image. In the proposed watermark embedding process, the protected digital image is first transformed into the DWT fre-quency domain and then each digital watermark bit is effectively embedded into four DWT coefficients using the proposed pattern mapping method. From the experi-mental results, we see that a digital watermark of accept-able quality can be extracted from an attacked water-marked image that has undergone the processes of image cropping, JPEG lossy compression, destructive signal, and even mixed attacks; that is, the proposed digital wa-termarking technique has an excellent robust property.
关键词：Discrete wavelet transformation; digital watermarking technique; intellectual property right
