AN INVESTIGATION OF DIFFERENT VIDEO WATERMARKING TECHNIQUES

Watermarking is an advanced technology that identifies to solve the problem of illegal manipulation and distribution of digital data. It is the art of hiding the copyright information into host such that the embedded data is imperceptible. The covers in the forms of digital multimedia object, namely image, audio and video. The extensive literature collected related to the performance improvement of video watermarking techniques is critically reviewed and presented in this paper. Also, comprehensive review of the literature on the evolution of various video watermarking techniques to achieve robustness and to maintain the quality of watermarked video sequences

Digital rights management techniques for H.264 video

This work aims to present a number of low-complexity digital rights management (DRM) methodologies for the H.264 standard. Initially, requirements to enforce DRM are analyzed and understood. Based on these requirements, a framework is constructed which puts forth different possibilities that can be explored to satisfy the objective. To implement computationally efficient DRM methods, watermarking and content based copy detection are then chosen as the preferred methodologies. The first approach is based on robust watermarking which modifies the DC residuals of 4×4 macroblocks within I-frames. Robust watermarks are appropriate for content protection and proving ownership. Experimental results show that the technique exhibits encouraging rate-distortion (R-D) characteristics while at the same time being computationally efficient. The problem of content authentication is addressed with the help of two methodologies: irreversible and reversible watermarks. The first approach utilizes the highest frequency coefficient within 4×4 blocks of the I-frames after CAVLC en- tropy encoding to embed a watermark. The technique was found to be very effect- ive in detecting tampering. The second approach applies the difference expansion (DE) method on IPCM macroblocks within P-frames to embed a high-capacity reversible watermark. Experiments prove the technique to be not only fragile and reversible but also exhibiting minimal variation in its R-D characteristics. The final methodology adopted to enforce DRM for H.264 video is based on the concept of signature generation and matching. Specific types of macroblocks within each predefined region of an I-, B- and P-frame are counted at regular intervals in a video clip and an ordinal matrix is constructed based on their count. The matrix is considered to be the signature of that video clip and is matched with longer video sequences to detect copies within them. Simulation results show that the matching methodology is capable of not only detecting copies but also its location within a longer video sequence. Performance analysis depict acceptable false positive and false negative rates and encouraging receiver operating charac- teristics. Finally, the time taken to match and locate copies is significantly low which makes it ideal for use in broadcast and streaming applications

Human Vision Models of Perceptual Image Distortions

Digital media's prevalence in today's society is placing an increasing strain on the technology to provide, transmit and store these contents. The demand for higher quality content in digital media has led to drastic increase in storage requirements over the past three decades. To meet the challenge of storing and securing digital media, this thesis proposes an insight into how the human vision system (HVS) can be characterized to determine thresholds of visibility of visual distortions. The use of these results can increase the amount of watermarking information applied to an image as well as applications in quantization error detection. In this thesis, we first propose a framework for predicting the regions of natural images that visually disguise distortions created as a result of modification of wavelet domain coefficients. The visual error perception algorithm adaptively predicts the visual perceptibility threshold of spread spectrum watermarking added in the wavelet subband. Spatial statistical feature maps combined with ground truth data from psychophysical experiments enabled the generation of an activity scaling parameter that evaluates the masking thresholds of image regions. We also demonstrate the correlation with an image quality assessment algorithm to the detectability of distortions in an image. Subsequently the algorithm is combined with a compression scheme to yield compressed images of higher visual quality. Secondly, we presents the results of another psychophysical experiment designed to investigate the effect of a scene's context on the detection of distortions presented in natural-image patches. Via a two-alternative forced-choice experiment, we measured thresholds for detecting 6.2 c/deg gabor target in image patches which were placed in various image surrounds (contexts), including various textures, a solid-gray background, and the patch's original context. The contexts were adjusted using histogram specification to control for differences in brightness, contrast, and other first-order statistical properties of the luminance distribution. Our results revealed that the context in which a patch is placed does indeed affect the ability to detect distortions in that patch. The findings suggest that characterization and implementation of a human visual system's ability to detect errors has potential in providing perceivable greater quality in image applications.School of Electrical & Computer Engineerin

A Video Steganography Method based on Transform Block Decision for H.265/HEVC

High definition video application has drawn a lot of interest both from academy and industry. The relevant latest video coding technology, H.265/HEVC has been a promising area for video steganography. In this paper, we present a novel and efficient video steganography method based on transform block decision for H.265. In order to improve the visual quality of carrier video, we analyze the embedding error of data hiding with modifying partitioning parameters of CB, PB and TB, and modify the transform block decision to embed secret message and update corresponding residuals synchronously. In order to limit embedding error, we utilize an efficient embedding mapping rule which can embed N (N>1) bits message and at most modify one bit transform partitioning flag. Our experimental results show that the proposed method can achieve better visual quality, larger embedding capacity and less bit-rate increase than state-of-the-art researches

Study and Implementation of Watermarking Algorithms

Water Making is the process of embedding data called a watermark into a multimedia object such that watermark can be detected or extracted later to make an assertion about the object. The object may be an audio, image or video. A copy of a digital image is identical to the original. This has in many instances, led to the use of digital content with malicious intent. One way to protect multimedia data against illegal recording and retransmission is to embed a signal, called digital signature or copyright label or watermark that authenticates the owner of the data. Data hiding, schemes to embed secondary data in digital media, have made considerable progress in recent years and attracted attention from both academia and industry. Techniques have been proposed for a variety of applications, including ownership protection, authentication and access control. Imperceptibility, robustness against moderate processing such as compression, and the ability to hide many bits are the basic but rat..

Digital watermarking and novel security devices

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