1,105 research outputs found
A NOVEL JOINT PERCEPTUAL ENCRYPTION AND WATERMARKING SCHEME (JPEW) WITHIN JPEG FRAMEWORK
Due to the rapid growth in internet and multimedia technologies, many new
commercial applications like video on demand (VOD), pay-per-view and real-time
multimedia broadcast etc, have emerged. To ensure the integrity and confidentiality of
the multimedia content, the content is usually watermarked and then encrypted or vice
versa. If the multimedia content needs to be watermarked and encrypted at the same
time, the watermarking function needs to be performed first followed by encryption
function. Hence, if the watermark needs to be extracted then the multimedia data
needs to be decrypted first followed by extraction of the watermark. This results in
large computational overhead. The solution provided in the literature for this problem
is by using what is called partial encryption, in which media data are partitioned into
two parts - one to be watermarked and the other is encrypted. In addition, some
multimedia applications i.e. video on demand (VOD), Pay-TV, pay-per-view etc,
allow multimedia content preview which involves „perceptual‟ encryption wherein all
or some selected part of the content is, perceptually speaking, distorted with an
encryption key. Up till now no joint perceptual encryption and watermarking scheme
has been proposed in the literature.
In this thesis, a novel Joint Perceptual Encryption and Watermarking (JPEW)
scheme is proposed that is integrated within JPEG standard. The design of JPEW
involves the design and development of both perceptual encryption and watermarking
schemes that are integrated in JPEG and feasible within the „partial‟ encryption
framework. The perceptual encryption scheme exploits the energy distribution of AC
components and DC components bitplanes of continuous-tone images and is carried
out by selectively encrypting these AC coefficients and DC components bitplanes.
The encryption itself is based on a chaos-based permutation reported in an earlier
work. Similarly, in contrast to the traditional watermarking schemes, the proposed
watermarking scheme makes use of DC component of the image and it is carried out
by selectively substituting certain bitplanes of DC components with watermark bits.
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Apart from the aforesaid JPEW, additional perceptual encryption scheme, integrated
in JPEG, has also been proposed. The scheme is outside of joint framework and
implements perceptual encryption on region of interest (ROI) by scrambling the DCT
blocks of the chosen ROI.
The performances of both, perceptual encryption and watermarking schemes are
evaluated and compared with Quantization Index modulation (QIM) based
watermarking scheme and reversible Histogram Spreading (RHS) based perceptual
encryption scheme. The results show that the proposed watermarking scheme is
imperceptible and robust, and suitable for authentication. Similarly, the proposed
perceptual encryption scheme outperforms the RHS based scheme in terms of number
of operations required to achieve a given level of perceptual encryption and provides
control over the amount of perceptual encryption. The overall security of the JPEW
has also been evaluated. Additionally, the performance of proposed separate
perceptual encryption scheme has been thoroughly evaluated in terms of security and
compression efficiency. The scheme is found to be simpler in implementation, have
insignificant effect on compression ratios and provide more options for the selection
of control factor
Improving Robustness of TCM-based Robust Steganography with Variable Robustness
Recent study has found out that after multiple times of recompression, the
DCT coefficients of JPEG image can form an embedding domain that is robust to
recompression, which is called transport channel matching (TCM) method. Because
the cost function of the adaptive steganography does not consider the impact of
modification on the robustness, the modified DCT coefficients of the stego
image after TCM will change after recompression. To reduce the number of
changed coefficients after recompression, this paper proposes a robust
steganography algorithm which dynamically updates the robustness cost of every
DCT coefficient. The robustness cost proposed is calculated by testing whether
the modified DCT coefficient can resist recompression in every step of STC
embedding process. By adding robustness cost to the distortion cost and using
the framework of STC embedding algorithm to embed the message, the stego images
have good performance both in robustness and security. The experimental results
show that the proposed algorithm can significantly enhance the robustness of
stego images, and the embedded messages could be extracted correctly at almost
all cases when recompressing with a lower quality factor and recompression
process is known to the user of proposed algorithm.Comment: 15 pages, 5 figures, submitted to IWDW 2020: 19th International
Workshop on Digital-forensics and Watermarkin
Multiple image watermarking using the SILE approach
Digital copyright protection has attracted a great spectrum of studies. One of the optimistic techniques is digital watermarking. Many digital watermarking algorithms were proposed in recent literature. One of the highly addressed issues within the watermarking literature is robustness against attacks. Considering this major issue, we propose a new robust image watermarking scheme. The proposed watermarking scheme achieves robustness by watermarking several images simultaneously. It firstly splits the watermark (which is a binary logo) into multiple pieces and then embeds each piece in a separate image, hence, this technique is termed 'Multiple Images Watermarking'. The binary logo is generated by extracting unique features from all the images which have to be watermarked. This watermark is first permuted and then embedded using SILE algorithm [7]. Permutation is important step to uniformly distribute the unique characteristics acquired from multiple logos. The proposed watermarking scheme is robust against a variety of attacks including Gamma Correction, JPEG, JPEG2000, Blur, Median, Histogram Equalization, Contrast, Salt and Pepper, Resize, Crop, Rotation 90, Rotation 180, Projective, Row Column Blanking and Row Column Copying and Counterfeit attack
Locally Adaptive Resolution (LAR) codec
The JPEG committee has initiated a study of potential technologies dedicated to future generation image compression systems. The idea is to design a new norm of image compression, named JPEG AIC (Advanced Image Coding), together with advanced evaluation methodologies, closely matching to human vision system characteristics. JPEG AIC thus aimed at defining a complete coding system able to address advanced functionalities such as lossy to lossless compression, scalability (spatial, temporal, depth, quality, complexity, component, granularity...), robustness, embed-ability, content description for image handling at object level... The chosen compression method would have to fit perceptual metrics defined by the JPEG community within the JPEG AIC project. In this context, we propose the Locally Adaptive Resolution (LAR) codec as a contribution to the relative call for technologies, tending to fit all of previous functionalities. This method is a coding solution that simultaneously proposes a relevant representation of the image. This property is exploited through various complementary coding schemes in order to design a highly scalable encoder. The LAR method has been initially introduced for lossy image coding. This efficient image compression solution relies on a content-based system driven by a specific quadtree representation, based on the assumption that an image can be represented as layers of basic information and local texture. Multiresolution versions of this codec have shown their efficiency, from low bit rates up to lossless compressed images. An original hierarchical self-extracting region representation has also been elaborated: a segmentation process is realized at both coder and decoder, leading to a free segmentation map. This later can be further exploited for color region encoding, image handling at region level. Moreover, the inherent structure of the LAR codec can be used for advanced functionalities such as content securization purposes. In particular, dedicated Unequal Error Protection systems have been produced and tested for transmission over the Internet or wireless channels. Hierarchical selective encryption techniques have been adapted to our coding scheme. Data hiding system based on the LAR multiresolution description allows efficient content protection. Thanks to the modularity of our coding scheme, complexity can be adjusted to address various embedded systems. For example, basic version of the LAR coder has been implemented onto FPGA platform while respecting real-time constraints. Pyramidal LAR solution and hierarchical segmentation process have also been prototyped on DSPs heterogeneous architectures. This chapter first introduces JPEG AIC scope and details associated requirements. Then we develop the technical features, of the LAR system, and show the originality of the proposed scheme, both in terms of functionalities and services. In particular, we show that the LAR coder remains efficient for natural images, medical images, and art images
Robust image steganography against lossy JPEG compression based on embedding domain selection and adaptive error correction
Transmitting images for communication on social networks has become routine,
which is helpful for covert communication. The traditional steganography
algorithm is unable to successfully convey secret information since the social
network channel will perform lossy operations on images, such as JPEG
compression. Previous studies tried to solve this problem by enhancing the
robustness or making the cover adapt to the channel processing. In this study,
we proposed a robust image steganography method against lossy JPEG compression
based on embedding domain selection and adaptive error correction. To improve
anti-steganalysis performance, the embedding domain is selected adaptively. To
increase robustness and lessen the impact on anti-steganalysis performance, the
error correction capacity of the error correction code is adaptively adjusted
to eliminate redundancy. The experimental results show that the proposed method
achieves better anti-steganalysis and robustness
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