DCT Based Grey Scale Still Image Watermarking Using 1-D Walsh Code and Biometric Protection

This paper presents a technique using one dimensional Walsh coding to improve the robustness of watermarking in gray scale digital still images. The proposed technique inserts bits of binary biometric image in the DCT blocks of a digital image. During the proposed method, the 1-D Walsh functions are used to encode the fingerprint before being embedded in the host image. The application of Walsh coding is made using the horizontal 1-D Walsh coding. By utilizing this type of coding, each row of the fingerprint’s vectors will be replaced by its equivalent Walsh code where they will make a queue horizontally to get the modulated signal. During the decoding process, the original fingerprint’s bits are recognized by the use of odd and even functions. The proposed technique retains the image quality and produces robustness against JPEG compression.