Wavelet Based Watermarking Technique using Digital Images

Abstract

Watermarking is highly demanding in recent times for the protection of multimedia data in network environment from illegal copying, violation of copyright, authentication etc while compression of multimedia signals is essential to save storage space and time to transmit the data. However, the working principles of watermarking and compression seem to be different as perceptual data coding removes inherent redundancy during compression. Compression technique reduces the number of bits in image, but produces better quality of image. Image compression plays very important role in image processing when we want to send large images on the internet. Generally threat to the image is increased on the internet, so compressed image is send to make optimal use of network band-width. Image is easily changed on the internet intentionally or unintentionally. To make sure that the correct image is being delivered at the other end, so we embed watermark to the image .Though watermarking increases the size of the uncompressed image but it has to be done to achieve high degree of robustness. Image storage and transmission have created an important and increasing part for the compression techniques. The main aim of compression is to reduce the number of bits as much as possible, while keeping the pixel resolution and the visual quality of the reconstructed image as close to the original image as possible. The redundancy and similarity among different images make compression easy.