Multimedia fingerprinting (robust hashing) as a content identification technology is emerging as an effective tool
for preventing unauthorized distribution of commercial content through user generated content (UGC) sites.
Research in the field has mainly considered content types with slow distribution cycles, e.g. feature films, for
which reference fingerprint ingestion and database indexing can be performed offline. As a result, research focus
has been on improving the robustness and search speed.
Live events, such as live sports broadcasts, impose new challenges on a fingerprinting system. For instance,
highlights from a soccer match are often available-and viewed-on UGC sites well before the end of the match.
In this scenario, the fingerprinting system should be able to ingest and index live content online and offer
continuous search capability, where new material is identifiable within minutes of broadcast. In this paper, we
concentrate on algorithmic and architectural challenges we faced when developing a video fingerprinting solution
for live events. In particular, we discuss how to effectively utilize fast sorting algorithms and a master-slave
architecture for fast and continuous ingestion of live broadcasts.
Electronic Music Distribution (EMD) is undergoing two fundamental shifts. The delivery over wired broadband
networks to personal computers is being replaced by delivery over heterogeneous wired and wireless networks,
e.g. 3G and Wi-Fi, to a range of devices such as mobile phones, game consoles and in-car players. Moreover,
restrictive DRM models bound to a limited set of devices are being replaced by flexible standards-based DRM
schemes and increasingly forensic tracking technologies based on watermarking. Success of these EMD services
will partially depend on scalable, low-complexity and bandwidth eficient content protection systems.
In this context, we propose a new partial encryption scheme for Advanced Audio Coding (AAC) compressed
audio which is particularly suitable for emerging EMD applications. The scheme encrypts only the scale-factor
information in the AAC bitstream with an additive one-time-pad. This allows intermediate network nodes to
transcode the bitstream to lower data rates without accessing the decryption keys, by increasing the scale-factor
values and re-quantizing the corresponding spectral coeficients. Furthermore, the decryption key for each user
is customized such that the decryption process imprints the audio with a unique forensic tracking watermark.
This constitutes a secure, low-complexity watermark embedding process at the destination node, i.e. the player.
As opposed to server-side embedding methods, the proposed scheme lowers the computational burden on servers
and allows for network level bandwidth saving measures such as multi-casting and caching.
Successful watermarking algorithms have already been developed for various applications ranging from meta-data tagging to forensic tracking. Nevertheless, it is commendable to develop alternative watermarking techniques that provide a broader basis for meeting emerging services, usage models and security threats. To this end, we propose a new multiplicative watermarking technique for video, which is based on the principles of our successful MASK audio watermark. <i>Audio</i>-MASK has embedded the watermark by modulating the short-time envelope of the audio signal and performed detection using a simple envelope detector followed by a SPOMF (symmetrical phase-only matched filter). <i>Video</i>-MASK takes a similar approach and modulates the image luminance envelope. In addition, it incorporates a simple model to account for the luminance sensitivity of the HVS (human visual system). Preliminary tests show algorithms transparency and robustness to lossy compression.
The goal of image steganography is to embed information in a cover
image using modifications that are undetectable. In actual practice,
however, most techniques produce stego images that are perceptually
identical to the cover images but exhibit statistical irregularities
that distinguish them from cover images. Statistical steganalysis
exploits these irregularities in order to provide the best
discrimination between cover and stego images. In general, the process
utilizes a heuristically chosen feature set along with a classifier
trained on suitable data sets. In this paper, we propose an
alternative feature set for steganalysis based on rate-distortion
characteristics of images. Our features are based on two key
observations: i) data hiding methods typically increase the image
entropy in order to encode hidden messages; ii) data hiding methods
are limited to the set of small, imperceptible distortions. The proposed
feature set is used as the basis of a steganalysis algorithm and its
performance is investigated using different data hiding methods.
Proc. SPIE. 5020, Security and Watermarking of Multimedia Contents V
KEYWORDS: Image compression, Imaging systems, Signal attenuation, Image processing, Image restoration, Digital watermarking, Data processing, Digital imaging, Reconstruction algorithms, Analog electronics
A novel framework is proposed for lossless authentication watermarking of images which allows authentication and recovery of original images without any distortions. This overcomes a significant limitation of traditional authentication watermarks that irreversibly alter image data in the process of watermarking and authenticate the watermarked image rather than the original. In particular, authenticity is verified before full reconstruction of the original image, whose integrity is inferred from the reversibility of the watermarking procedure. This reduces computational requirements in situations when either the verification step fails or the zero-distortion reconstruction is not required. A particular instantiation of the framework is implemented using a hierarchical authentication scheme and the lossless generalized-LSB data embedding mechanism. The resulting algorithm, called localized lossless authentication watermark (LAW), can localize tampered regions of the image; has a low embedding distortion, which can be removed entirely if necessary; and supports public/private key authentication and recovery options. The effectiveness of the framework and the instantiation is demonstrated through examples.
A novel watermarking algorithm for watermarking low bit-rate MPEG-4 compressed video is developed and evaluated in this paper. Spatial spread spectrum is used to invisibly embed the watermark into the host video. A master synchronization template is also used to combat geometrical distortion such as cropping, scaling, and rotation. The same master synchronization template is used for watermarking all video objects (VOP) in the bit-stream, but each object can be watermarked with a unique payload. A gain control algorithm is used to adjust the local gain of the watermark, in order to maximize watermark robustness and minimize the impact on the quality of the video. A spatial and temporal drift compensator is used to eliminate watermark self-interference and the drift in quality due to AC/DC prediction in I-VOPs and motion compensation in P- and B-VOPs, respectively. Finally, a bit-rate controller is used to maintain the data-rate at an acceptable level after embedding the watermark. The developed watermarking algorithm is tested using several bit-streams at bit-rates ranging from 128-750 Kbit/s. The visibility and the robustness of the watermark after decompression, rotation, scaling, sharpening, noise reduction, and trans-coding are evaluated.
Digital video has become increasingly susceptible to spatio-temporal manipulations as a result of recent advances in video editing tools. In this paper, we propose a secure and flexible fragile digital video authentication watermark which also enables the self-recovery of video content after malicious manipulations. In the proposed block-based method, the watermark payload of a block is composed of two parts: authentication and recovery packets. The authentication packet is a digital signature with a special structure and carries the spatio-temporal position of the block. The digital signature guarantees the authenticity and integrity of the block as well as the recovery packet, whereas the localization information prevents possible cut & paste attacks. On the other hand, the recovery packet contains a highly compressed version of a spatio-temporally distant block. This information enables the recovery of the distant block, upon detection of tampering by its authentication packet. A spatio-temporal interleaving scheme and a simple multiple description coding mechanism increase the probability of self recovery by diffusing recovery information throughout the sequence. Finally, watermark payload is embedded by least significant bit modulation.
Proc. SPIE. 4314, Security and Watermarking of Multimedia Contents III
KEYWORDS: Image processing algorithms and systems, Detection and tracking algorithms, Sensors, Image segmentation, Image processing, Digital watermarking, Feature extraction, Image registration, Digital imaging, Signal processing
In this paper, we present an analysis of feature-based geometry invariant watermarking algorithms. A discussion of the requirements on each building block is followed by potential solutions to meet these requirements. Furthermore, we present theoretical and practical limitations of these solutions via examples. In particular, segmentation based feature point extractors and triangulation based elementary patch formations are evaluated.