Over the past few years a number of research papers about reversible watermarks has been produced. Reversible watermarking is a novel category of watermarking schemes. It not only can strengthen the ownership of the original media but also can completely recover the original media from the watermarked media. This feature is suitable for some important media, such as medical and military images, because these kinds of media do not allow any losses. The aim of this paper is to define the purpose of reversible watermarking, reflecting recent progress, and provide some research issues for the future.

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Reversible Watermarking: Current Status and Key Issues

This paper proposes a lossless data hiding technique for JPEG images based on histogram pairs It embeds data into the JPEG quantized 8x8 block DCT coefficients and can achieve good performance in terms of PSNR versus payload through manipulating histogram pairs with optimum threshold and optimum region of the JPEG DCT coefficients It can obtain higher payload than the prior arts In addition, the increase of JPEG file size after data embedding remains unnoticeable These have been verified by our extensive experiments

Reversible data hiding for JPEG images based on histogram pairs

Lossless data hiding in JPEG bitstream

We propose an algorithm to embed data directly in the bitstream of JPEG imagery. The motivation for this approach is that images are seldom available in uncompressed form. Algorithms that operate in spatial domain, or even in coefficient domain, require full (or at best) partial decompression. Our approach exploits the fact that only a fraction of JPEG code space is actually used by available encoders. Data embedding is performed by mapping a used variable length code (VLC) to an unused VLC. However, standard viewers unaware of the change will not properly display the image. We address this problem by a novel error concealment technique. Concealment works by remapping run/size values of marked VLCs so that standard viewers do not lose synchronization and displays the image with minimum loss of quality. It is possible for the embedded image to be visually identical to the original even though the two files are bitwise different. The algorithm is fast and transparent and embedding is reversible and file-size preserving. Under certain circumstances, file size may actually decrease despite carrying a payload.

Data Embedding in JPEG Bitstream by Code Mapping

This article presents a detailed discussion of different prospects of digital image watermarking. This discussion of watermarking included: brief comparison of similar information security techniques, concept of watermark embedding and extraction process, watermark characteristics and applications, common types of watermarking techniques, major classification of watermarking attacks, brief summary of various secure watermarking techniques. Further, potential issues and some existing solutions are provided. Furthermore, the performance comparisons of the discussed techniques are presented in tabular format. Authors believe that this article contribution will provide as catalyst for potential researchers to implement efficient watermarking systems.

Secure data hiding techniques: a survey

In lossless watermarking, it is possible to completely remove the embedding distortion from the watermarked image
and recover an exact copy of the original unwatermarked image. Lossless watermarks found applications in fragile
authentication, integrity protection, and metadata embedding. It is especially important for medical and military
images. Frequently, lossless embedding disproportionably increases the file size for image formats that contain lossless
compression (RLE BMP, GIF, JPEG, PNG, etc...). This partially negates the advantage of embedding information as
opposed to appending it. In this paper, we introduce lossless watermarking techniques that preserve the file size. The
formats addressed are RLE encoded bitmaps and sequentially encoded JPEG images. The lossless embedding for the
RLE BMP format is designed in such a manner to guarantee that the message extraction and original image
reconstruction is insensitive to different RLE encoders, image palette reshuffling, as well as to removing or adding
duplicate palette colors. The performance of both methods is demonstrated on test images by showing the capacity,
distortion, and embedding rate. The proposed methods are the first examples of lossless embedding methods that
preserve the file size for image formats that use lossless compression.

/pdf/lossless-data-embedding-with-file-size-preservation-4s3xkf5czg.pdf

Lossless data embedding with file size preservation

For most data hiding applications, the main source of concern is the effect of lossy compression on hidden information. The objective of watermarking is fundamentally in conflict with lossy compression. The latter attempts to remove all irrelevant and redundant information from a signal, while the former uses the irrelevant information to mask the presence of hidden data. Compression on a watermarked image can significantly affect the retrieval of the watermark. Past investigations of this problem have heavily relied on simulation. It is desirable not only to measure the effect of compression on embedded watermark, but also to control the embedding process to survive lossy compression. In this paper, we focus on oblivious watermarking by assuming that the watermarked image inevitably undergoes JPEG compression prior to watermark extraction. We propose an image-adaptive watermarking scheme where the watermarking algorithm and the JPEG compression standard are jointly considered. Watermark embedding takes into consideration the JPEG compression quality factor and exploits an HVS model to adaptively attain a proper trade-off among transparency, hiding data rate, and robustness to JPEG compression. The scheme estimates the image-dependent payload under JPEG compression to achieve the watermarking bit allocation in a determinate way, while maintaining consistent watermark retrieval performance.

http://biblio.telecom-paristech.fr/cgi-bin/download.cgi?id=2231

Qing Chen

Papers

Lossless data embedding with file size preservation

Oblivious image watermarking combined with JPEG compression