关键词: 小波变换, 快速傅立叶变换, 相关理论, 锐化处理, 模板匹配

Abstract: A new blind digital watermarking algorithm was proposed. In embedding process, an unit module was used to represent a pixel, in detecting process correlation value of the unit module and watermarked image wavelet coefficients was calculated and was processed with proper threshold to detect the embedded watermark. The detecting process doesnt need original image and position information, so the scheme realizes blind detecting and self-synchronization. Sharpening the watermarked image with Laplacian before detecting could make the watermarking scheme more robust to attacks and get better detecting result. Furthermore, adding sharpening step could lower the demand of embedding strength without affect the detecting result. Thus it improved watermark invisibility. Experiments show that the algorithm has good invisibility and robustness.

Key words: wavelet transform, fast Fourier transform, correlation theory, sharpening processing, module matching