| Popis: |
The central idea of this paper is to propose an algorithm that embeds the watermark information in host image. The image is divided into a non-overlapping blocks of size 2x2. A matrix is constructed by obtaining mean from every block. With the help of Fibonacci transform, the resultant matrix is scrambled for three times to improve security. Based on the median value a binary watermark is constructed from the scrambled matrix, which is to be embedded within the host image. The operation of embedding and extraction of watermark is done in high frequency domain of Discrete Wavelet Transform. The proposed technique is checked against different noise attacks like salt & pepper and Gaussian, median filtering, image adjustment and histogram equalization. Peak Signal to Noise Ratio (PSNR) and Similarity Ratio (SR) are computed to measure image quality. This watermarking scheme deals with the extraction of the watermark information in the absence of original image, hence the blind scheme was obtained. |
