An enhanced technique for digital watermarking using multilevel DWT and error correcting codes

Abstract

Digital Watermarking has attracted researchers’ attention because of its useful applications and, over the past decades, great efforts have been made to develop digital watermarking techniques and algorithms. Most researches use different transform techniques to enhance the robustness and quality of extracted watermark. This paper presents an enhanced technique for digital image watermarking based on multilevel Discrete Wavelet Transform (DWT) in conjunction with the well-known RS codes over finite fields. To observe and appreciate the significance of using the error correcting codes technique for enhancing the digital watermarking performance against attacks, a series of experiments were conducted. The enhanced methodology, presented and implemented in this research, achieved a very good performance. Regarding the significance of using error correcting codes in conjunction with DWT transform digital image watermarking; it was shown that, in all cases investigated, for all the attacks considered, there was an increase in the robustness of the digital watermark, in terms of the performance measure SSIM values. In some cases, it improves, to almost 27 times, the case without using error correcting codes. Among each class of codes, for all the attacks, Reed-Solomon block codes of length n=255 over the Galois field GF(2^8) with k=135, performs better than all others.