Description

The common methodology in data embedding is that in the sender side the data that is to be hided is placed with in the pixel values of the cover image producing the stego image. In the receiver side the embedded data in the stego image is retrieved by reversing the same process that is employed for embedding. The data that is to be hided is embedded in the images using DCT is proposed. The input cover and watermark images were obtained. The obtained images were combined with the help of calculation of average of cover and the watermark images. The images were converted into string for transmission. In the receiver side the string is converted into integer inorder to retrieve the data. Watermarking is a basic secure communication method. It is used for embedding a recognizable pattern in media in such a manner that modification of the media also modifies the pattern, thus making it easy to detect the modification. This technique and its variants have many practical applications pertaining to secure communications, media verification, etc. Digital image watermarking is a technique for embedding data within an image signal in such a way that the original and the modified image signals are essentially identical. The embedded data can be used for various purposes such as secure communication in military applications, owner identification and verifiation, content authentication, etc. In this study a watermark image signal is hidden in a message image signal by using a discrete cosine transform (DCT) domain approach. The tests of fidelity between the original and the watermarked signal and robustness applied to the watermarked signal. The results with both the Human Visual System (HVS) and numeric/graphic aspects are presented. The results show that an embedded watermark is not easily detectable using either the HVS or other techniques. Additionally, it can be detected successfully in the simulation domain, but it may be susceptible to some noise and channel limitations in the real world replaced from the original frames. The performance of the process is measured with the help of PSNR, MSE and Detection rate.