Adaptive Reversible Visible Watermarking Based on Total Variation for BTC-Compressed Images

Few previous Reversible Visible Watermarking(RVW)schemes have both good transparency and watermark visibility.An adaptive RVW scheme that integrates Total Variation and visual perception in Block Truncation Coding(BTC)compressed domain,called TVB-RVW is proposed in this paper.A new mean image estimation method for BTC-compressed images is first developed with the help of Total Variation.Then,a visual perception factor computation model is devised by fusing texture and luminance characteristics.An adaptive watermark embedding strategy is used to embed the visible watermark with the effect of the visual perception factor in the BTC domain.Moreover,a lossless embedding method of the encrypted visible watermark is exploited to deter illegal watermark removal.The visible watermark can be removed since the visual perception factor and the estimated mean image remain unchanged before and after watermark embedding.Extensive experiments validate the superiority of the proposed algorithm over previous RVW schemes in BTC in terms of the visual quality of watermarked images and watermark visibility,and it can achieve a good balance between transparency and watermark visibility.

Spatial Domain Technique for Visible Watermarking

A new technique for embedding visible watermarks into a digital image isdescribed in this paper, which uses statistical properties of each pixel and its immediatesurrounding pixels in the host image, and also the statistical properties of the host image and thatof the image to be embedded (watermark), as the pixels in the host image are replaced one by one bythe pixels in the watermark image. The aim is to establish a relationship between pixels in theimages that will make the embedded watermark robust and semitransparent, and to minimize errorscaused by watermark addition and subtraction. Also, the original image can be completelyreconstructed from the watermarked images.

Visible Watermarking Technique for MPEG-2 Downsampling Transcoding in the DCT Domain

To locate the right places for embedding watermark signals, and to set the proper streng-th of the embedded watermark signal are two critical problems for obtaining a robust and transpar-ent watermark in color images. In this paper, a DCT domain visible watermarking scheme based on the luminance and texture features and alligned with transcoding from MPEG-2 to MPEG-1 is proposed. In this scheme, the location of the visible watermark is chosen at the block with minimum number of nonzero DCT coefficients in the I-frames. When embedding the visible watermark （ such as video DC image ） into the unmarked original image, the embedding factors are determined with the local luminance feature and texture features of the original image and watemark image by utilizing DC and 3AC coefficients only. Experimental results demonstrate that the proposed scheme not only provides good fidelity and robustness against MPEG-2 downscaling transcoding, but also achieves a low Computational complexity.

DCT based multipurpose watermarking technique for image copyright notification and protection

A multipurpose image watermarking technique based on DCT is proposed to notify and protect the copyright of digital products. In order to achieve this objective, the DCT coefficients of each image block are divided into two parts for embedding the visible and invisible watermarks. The visible watermark is embedded in each DC DCT coefficient and most of the AC DCT coefficients of every block, and the invisible watermark in the rest. Based on the characteristics of Human Visual System (HVS), the embedding strength of the visible watermark is varied in accordance with the underlying content of the host image. The invisible watermark is embedded in a quaternity of midrange frequencies. Experimental results show that the visible watermark is hard to remove and the invisible watermark is robust to common digital signal processing operations.