Improving CRT based watermarking using integer wavelet projection

摘要

A new watermarking scheme is proposed in this paper to embed the watermark in the high frequency image region. Diagonal integer wavelet filter is used to generate the high frequency sub band to be projected using convolution algorithm within the resolution of host image to define the most high frequency pixels. This is aimed to improve quality within the same robustness from the previous CRT algorithm which embeds the watermark on the host image regardless of the frequency. The experiments are conducted to compare the quality and robustness of the CRT and proposed method. They are measured using Structural Similarity and Normalized Correlation. The result shows that the proposed method has better quality with the average value of 0.9995 compared to the CRT method which has average value of 0.9981. In the meantime the compression and additive noise are used to measure the robustness of both methods. The CRT and the proposed method have similar result in robustness. It has successfully improved the quality of the watermarked image and maintaining the robustness of the watermark as well.