Wavelet Based Color Image Watermarking Scheme Giving High Robustness and Exact Corelation

A good quality watermarking scheme should have maximum PSNR, ideally Correlation Factor equals to 1 and should have maximum watermark information hiding capacity. In this paper, a robust digital color image watermarking scheme based on ‘Discrete Wavelet Transform’ is implemented. The RGB color space is converted into YUV color space and then V component is selected for watermark embedding. The scrambled watermark is embedded in middle frequency sub band. The security levels are increased by generating PN sequence depending on periodicity of watermark image. The image scrambling is applied by Arnold Transform. The decomposition is done with ‘Haar’ which is simple, symmetric and orthogonal wavelet and the direct weighting factor is used in watermark embedding and extraction process. The scheme results in exact recovery of watermark with standard database images of size 512x512, giving Correlation Factor equals to 1. The PSNR with weighting factor 0.02 is up to 48.51 dBs. The presented scheme is non blind and embeds binary watermark of 64x64 size.