Robust data hiding for images

This paper describes a robust data embedding scheme, which uses a source and channel coding framework for data hiding. The data to be embedded, referred to as the signature data, is source coded by vector quantization and the indices obtained in the process are embedded in the transform coefficients of the host image. Transform coefficients of the host are grouped into vectors and perturbed using error-correcting codes derived from BCH codes. Compared to prior work in digital watermarking, the proposed scheme can handle a significantly large quantity of data such as a gray scale images. A trade-off between the quantity of hidden data and the quality of the watermarked image is achieved by varying the number of quantization levels for the signature, the code word length, and the scale factor for embedding. Experimental results on signature recovery from JPEG compressed watermarked images are included.