Watermark Embedding in DC Components of DCT for Binary Image

摘要

This paper investigates the feasibility of watermark embedding in the discrete cosine transform (DCT) domain for binary images. Watermark embedding is known difficult for binary images due to their binary nature. For frequency domain approach to binary image watermarking, a post-embedding bina-rization is a necessary step to ensure that the watermarked image is still a binary image. This step disturbs the watermark embed-ded and is likely to remove the watermark. We have succeeded in combating this interference by embedding watermarks in the DC components of DCT and employing a biased binarization thresh-old. This algorithm can be applied to binary images in general and experiments show that the embedding algorithm proposed can not only survive binarization, but also provide some degree of robustness against common image processing.