Blind watermarking technique for grey scale image using block level Discrete Cosine Transform (DCT)

Abstract

This paper presents a robust watermarking technique to copyright an image. Proposed technique is totally based on DCT and is different from most of the available techniques.We are embedding blockwise watermark against the noise, filtering and cropping attack. Before embedding the watermark for any host image we must calculate the gain factor. According to our approach gain factor will vary for two different host images . The experimental results show that in addition the invisibility and security, the scheme is also robust against signal processing.