Catálogo de publicaciones - libros

Distributing video contents via broadcasting network mechanisms has become a promising business opportunity for the entertainment industry. However, since content piracy is always a serious problem, broadcasted contents must be adequately protected. Rather than implementing sophisticate key-management schemes for access control, an animation broadcast system based on colorization techniques is proposed. In the proposed system, gray-level animation video sequences are delivered via broadcast mechanisms, such as multicast, to reduce the overhead in server processing and network bandwidth. Moreover, color seeds labeled with fingerprint codes are delivered to each client through low-bandwidth auxiliary connections and then used to generate high-quality full-color animations with slight differences between versions received by each client-side device. When a user illegally duplicates and distributes the received video, his identity can be easily found out by examining features extracted from the pirated video. The proposed scheme also shows good resistance to collusion attacks where two or more users cooperate to generate an illegal copy in expectation of getting rid of legal responsibility. The proposed scheme exhibits advantages in network bandwidth, system performance and content security.

In this paper, we propose an adaptive blind video watermarking method using video characteristics based on human visual system (HVS) in three-dimensional discrete cosine transform (3D-DCT) domain. In order to optimize the weight factors for watermarking, we classify the patterns of 3D-DCT cubes and the types of video segments by using the texture and motion information of 3D-DCT cubes. Then we embed an optimal watermark into the mid-range coefficients of 3D-DCT cubes by using the trained optimal weight factors. Experimental results show that the proposed method achieves better performance in terms of invisibility and robustness than the previous method under the various possible attacks such as MPEG compression, frame dropping, frame insertion and frame swapping to experimental videos.

In this paper, we propose an encryption algorithm to protect scalable video coding (SVC) bitstream and a method for conditional access control to consume the encrypted SVC bitstream. To design an encryption algorithm, we analyzed the encryption requirements to support scalability function in the scalable video and proposed an effective encryption method developed in the network abstraction layer (NAL). In addition, conditional access control scheme and key management scheme are proposed to consume the SVC bitstream protected with proposed method. Experiments were performed to verify the proposed method and results showed that proposed algorithms could provide an effective access control of scalable video as well as support a video encryption with scalability function.

This paper proposes a wavelet-based fragile watermarking scheme for secure image authentication. In the proposed scheme, the embedded watermark is generated using the discrete wavelet transform (DWT), and then the improved security watermark by scrambling encryption is embedded into the least significant bit (LSB) of the host image. The proposed algorithm not only possesses excellent tamper localization properties and greater security against many attacks, but also demonstrates a new useful feature that can indicate whether the modification made to the image is on the contents or the embedded watermark. If only the watermark is modified, the authenticity of the image is assured, instead of being declared as a counterfeit. Experimental results illustrate the effectiveness of our method.

Secure watermark embedding allows to securely embed a watermark into a piece of content at an untrusted user device without compromising the security of the watermark key, the watermark or the original. In this paper, we show how secure embedding can be achieved by using traditional watermarking schemes in conjunction with partial encryption techniques, which were primarily developed to facilitate fast encryption of media content. Based on this concept, we develop two new efficient secure embedding mechanisms, one for the MASK watermarking scheme operating on baseband audio and one for a spread spectrum watermarking scheme operating on MPEG-2 encoded video streams.

Robustness and security are the key issues in the development of image watermarking algorithm. A new rotation invariant security image watermarking algorithm based on steerable pyramid transform is proposed in this paper. The algorithm is characterized as follows: (1) the rotation invariance and robust watermarking are achieved concurrently on the same transform domain; (2) the rotation synchronization is obtained through template matching by using steerable pyramid transform, which satisfies the shiftability in orientation condition; (3) the watermarks are embedded into an oriented subband at angle θ , which can be interpolated with base filter kernels and used as a key in watermark detection to increase the security of watermark; (4) the watermark detector is designed based on the steerable vector HMM model. High robustness is observed against StirMark attacks and their joint attacks.

The pervasive distribution of digital images triggers an emergent need of authenticating degraded images by lossy compression and transmission. This paper proposes a robust content-based image authentication scheme for image transmissions over lossy channels. Content-based image authentication typically assesses authenticity based on a distance measure of feature differences between the testing image and its original. Commonly employed distance measures such as the Minkowski measures may not be adequate for content-based image authentication since they do not exploit statistical and spatial properties of the feature differences. This proposed error resilient scheme is based on a statistics- and spatiality-based measure ( SSM ) of feature differences. This measure is motivated by an observation that most malicious manipulations are localized whereas acceptable manipulations cause global distortions. Experimental results show that SSM is better than previous used measures in distinguishing malicious manipulations from acceptable ones, and the proposed SSM -based scheme is robust to transmission errors and other acceptable manipulations, and is sensitive malicious image modifications.