Experimental research of image digital watermark based on DWT technology

In view of the safety and genuineness protection of the image while traveling over the internet, a novel digital watermarking scheme based on discrete wavelet transform (DWT) is proposed. The theory of digital watermark based on DWT for electronic seal is discussed. The digital watermark is scrambled with logistic chaotic sequences to improve the security of the system. Then the watermark signals are converted into a binary sequence embedded to the high (HL and HH) frequency band of the document in DWT domain. The algorithm of how to embed and extract the watermark is shown in the paper. Image quality is checked with a number of widely used parameters such as PSNR, Normalized correlation and JPEG compression. The experimental results demonstrate the efficiency of the proposed scheme, which is practicality perfect by means of good balance between transparency and robustness.