원문정보
초록
영어
In order to improve watermark capacity, image quality and error correction capability of DFT-based watermark algorithm, this paper proposes a novel efficient image watermark algorithm based on DFT transform. Firstly, the watermark information is encoded by using hybrid error correcting code, and the watermark is embedded into an image, and the code ensures that the correct rate of watermark extraction is 100% in the condition of the watermarked image under attacks. Secondly, through changing the way of embedding watermark into the frequency domain data block, watermark capacity can be increased to 2 times of the original algorithm. Thirdly, through extending the frequency domain region of embedding watermark, visual effect of the watermarked image is obviously improved and watermark capacity can be increased. The experimental results show that the proposed algorithm is significantly better than the original algorithm in robustness, and it can ensure that the correct rate of watermark extraction is 100% after the watermarked image suffered with attacks, and the proposed algorithm and the original algorithm are basically the same in PSNR, and the proposed algorithm is better than the original algorithm in visual effect of watermarked image.
목차
1. Introduction
2. Analysis of the Performance of the Original DFT-based Watermark Algorithm
2.1. Transparency
2.2. Robustness
2.3. Shortcomings of the Original Algorithm
3. Compostion of Algorithm Improvement
3.1. Hybrid Error Correcting Code
3.2. Embed 2 Bits Watermark Value in Each 4×4 Block
3.3. Extend the Frequency Domain Region of Embedding Watermark
4. Proposed Watermarking Scheme
4.1. Watermark Embedding
4.2. Watermark Extraction
5. Experimental Results and Performance Analysis
5.1. Transparency
5.2. Robustness
6. Conclusions
References