An Efficient Method for Protecting Digital Watermark Data against Image Compression

Abstract

This paper presents an effective digital watermarking technique used for protecting the watermark data from the digital processing based data compression schemes such as JPEG compression standard. In this research work, a wavelet packet transform is considered, and applied in the watermark embedding process. Moreover, the direct sequence spread spectrum technique is used to generate the watermark retrieval process. From the experimental results, it is found that employing wavelet packet transform instead of ordinary wavelet transform improves the performance of digital watermarked image. Furthermore, the embedded watermark signal is robust against JPEG compression, at the compression rate up to 70%, requantizing, subsampling and rescaling processes, which is measured from the correctly retrieved watermark signal obtained after passing through those processes.