Content-adaptive Watermarking Research Articles

Content adaptive watermarking for multimedia fingerprinting

This paper presents a feasible system for multimedia fingerprinting. One of the important problems of fingerprinting is watermarking strategies for the fingerprints, in other words, where to embed and how to embed. We address these two major problems of fingerprint-watermarking for multimedia in the proposed content-adaptive watermarking scheme. First, the fingerprint codes are often very long if the applicable resisting ability to colluders and large customer bases are needed. As a result, the acute degradation of fingerprinted content may be unacceptable. We design a strength-decision algorithm, on the basis of neural networks, to adaptively embed the long-length fingerprints with suitable magnitudes to different image regions. This adaptive watermarking technique maintains the equilibrium of the robustness and the imperceptibility without the effort to deal with visual models. Second, we analyze the disturbance of collusion attacks on images and propose an optimization algorithm which can select better embedding positions to resist collusion attacks and preserve acceptable transparency of the watermark according to different multimedia contents. In addition, we consider the lossy property of multimedia watermarking and use a sequential detection strategy to identify colluders, which can tolerate erasures and errors possibly induced in the watermarking process or communication channel. Experimental results show the high detection correctness of traitor tracing. It implies that our fingerprinting system, constructed by applying c-TA code to the content-adaptive watermarking scheme and a sequential detection algorithm, is effective for multimedia application. One can replace the fingerprint codes in our system with other existing codes to obtain effective fingerprinting systems with higher tracing correctness and practical parameters (reasonable collusion-resilience and applicable size of customer bases).

Practical fingerprinting system for images

This paper presents a feasible system for image fingerprinting. Two important problems of fingerprinting are the design collusion-secure codes and the watermarking strategies for the fingerprints. We address these problems by proposing hierarchical fingerprint codes and a content adaptive watermarking scheme. It is challenging to find a practical collusion-secure code for fingerprinting because of the trade-offs between the fingerprint code's length, its collusion resiliency, and the size of the customer base. Therefore, instead of pursuing a high-performance code, we construct a new fingerprint code by concatenating existing codes using a hierarchical structure. The resulting code is efficient in decoding, much shorter than existing codes for similar parameters, and thus practical for real systems. In the fingerprinting, the codes are often very long if the applicable colluder-resisting ability and large customer bases are needed. The resulting acute degradation of fingerprinted content may be unacceptable. Hence the long-length watermark must be appropriately embedded into images to preserve the image quality. We design a strength-decision algorithm, on the basis of neural networks, to adaptively embed the long-length fingerprints with suitable magnitudes into different image regions. This adaptive watermarking technique maintains the combination of robustness and imperceptibility without the effort of dealing with visual models. In addition, we analyze the disturbance due to collusion attacks on images and propose an optimization algorithm that can select better embedding positions to resist collusion attacks and preserve acceptable transparency of the watermark according to different multimedia contents. Experimental results show the high detection correctness of the traitor tracing. It implies that our fingerprinting system, constructed by applying a hierarchical fingerprint code to the content-adaptive watermarking scheme, is effective for multimedia application.

DIGITAL IMAGE WATERMARKING CAPACITY ANALYSIS

In watermarking schemes, image can be considered as a communication channel to transmit messages. This paper presents a new adaptive capacity analysis scheme for image watermarking, realizes a content adaptive watermarking algorithm invisibly embedding the strongest watermark, and discusses the watermarking capacity of blind watermarking and non-blind watermarking. This paper also analyzes the relation between watermarking capacity and watermarking detection bit error rate (BER), and derives the relation between capacity and the limit of BER. According to the result of research, watermarking detection BER mainly influenced by the watermarking average energy and watermarking capacity. The BER rises with the increase of watermarking capacity.