Enhanced blind decoding of Tardos codes with new map-based functions

This paper presents a new decoder for probabilistic binary traitor tracing codes under the marking assumption. It is based on a binary hypothesis testing rule which integrates a collusion channel relaxation so as to obtain numerical and simple accusation functions. This decoder is blind as no estimation of the collusion channel prior to the accusation is required. Experimentations show that using the proposed decoder gives better performance than the well-known symmetric version of the Tardos decoder for common attack channels

An Efficient MSB Prediction-Based Method for High-Capacity Reversible Data Hiding in Encrypted Images

International audienceReversible data hiding in encrypted images (RDHEI) is an effective technique to embed data in the encrypted domain. An original image is encrypted with a secret key and during or after its transmission, it is possible to embed additional information in the encrypted image, without knowing the encryp-tion key or the original content of the image. During the decoding process, the secret message can be extracted and the original image can be reconstructed. In the last few years, RDHEI has started to draw research interest. Indeed, with the development of cloud computing, data privacy has become a real issue. However, none of the existing methods allow us to hide a large amount of information in a reversible manner. In this paper, we propose a new reversible method based on MSB (most significant bit) prediction with a very high capacity. We present two approaches, these are: high capacity reversible data hiding approach with correction of prediction errors and high capacity reversible data hiding approach with embedded prediction errors. With this method, regardless of the approach used, our results are better than those obtained with current state of the art methods, both in terms of reconstructed image quality and embedding capacity

An Efficient Data-hiding Method Based on Lossless JPEG2000 for a Scalable and Synchronized Visualization of 3D Terrains

International audienceReal-time on-line 3D visualization of terrain is a memory intensive process accompanied by considerably large data transfer across the network and thus data compression is inevitable. The upcoming standard of JPEG2000 is well suited for such network based transfers since it offers the additional advantage of resolution scalability resulting in incremental improvement of quality. The 3D visualization process is, essentially, the linking of the texture image with the terrain geometry obtained from DEM; the data are heterogeneous and normally involves more than one file. This work is concerned with the interleaving of these files into one jp2 file in a synchronized way so that the file format is conserved for compliance to the JPEG2000 standard. This synchronization is achieved by using a scalable data hiding method to embed the lossless wavelet transformed DEM in the corresponding lossless JPEG2000 coded texture. For the DEM and the texture, the level of transform is the same. With this approach the 3D visualization is efficient even if a small fraction of the initial data is transmitted

An Adaptive Spread Spectrum (SS) Synchronous Data Hiding Strategy for Scalable 3D Terrain Visualization

International audienceThe diversity of clients in today's network environment compels us to think about solutions that more than satisfy their needs according to their resources. For 3D terrain visualization this translates into two main requirements, namely the scalability and synchronous unification of a disparate data that requires at least two files, the texture image and its corresponding digital elevation model (DEM). In this work the scalability is achieved through the multiresolution discrete wavelet transform (DWT) of the JPEG2000 codec. For the unification of data, a simple DWT-domain spread spectrum (SS) strategy is employed in order to synchronously hide the DEM in the corresponding texture while conserving the JPEG2000 standard file format. Highest possible quality texture is renderable due to the reversible nature of the SS data hiding. As far as DEM quality is concerned, it is ensured through the adaptation of synchronization in embedding that would exclude some highest frequency subbands. To estimate the maximum tolerable error in the DEM according to a given viewpoint, a human visual system (HVS) based psycho-visual analysis is being presented. This analysis is helpful in determining the degree of adaptation in synchronization

Adaptively Synchronous Scalable Spread Spectrum (A4S) Data-Hiding Strategy for Three-Dimensional Visualization

International audienceWe propose an adaptively synchronous scalable spread spectrum (A4S) data-hiding strategy to integrate disparate data, needed for a typical 3-D visualization, into a single JPEG2000 for- mat file. JPEG2000 encoding provides a standard format on one hand and the needed multiresolution for scalability on the other. The method has the potential of being imperceptible and robust at the same time. While the spread spectrum (SS) methods are known for the high robustness they offer, our data-hiding strategy is removable at the same time, which ensures highest possible visualization qual- ity. The SS embedding of the discrete wavelet transform (DWT)- domain depth map is carried out in transform domain YCrCb com- ponents from the JPEG2000 coding stream just after the DWT stage. To maintain synchronization, the embedding is carried out while taking into account the correspondence of subbands. Since security is not the immediate concern, we are at liberty with the strength of embedding. This permits us to increase the robustness and bring the reversibility of our method. To estimate the maximum tolerable error in the depth map according to a given viewpoint, a human visual system (HVS)-based psychovisual analysis is also presented

A Lossy JPEG2000-based Data Hiding Method for Scalable 3D Terrain Visualization

International audienceThe data needed for 3D terrain visualization consists, essentially, of a texture image and its corresponding digital elevation model (DEM). A blind data hiding method is proposed for the synchronous unification of this disparate data whereby the lossless discrete wavelet transformed (DWTed) DEM is embedded in the tier-1 coded quantized and DWTed Y component of the texture image from the lossy JPEG2000 pipeline. The multiresolution nature of wavelets provides us the scalability that can cater for the diversity of client capacities in terms of computing, memory and network resources in today's network environment. The results have been interesting and for a bitrate as low as $0.012$ bit per pixel (bpp), a satisfactory visualization was realized. We compare the obtained results with those of a previous method that interrupt the lossless JPEG2000 codec immediately after the DWT step and embeds lossless DWTed DEM in the reversibly DWTed Y component of texture. The proposed method proved to be more effective in the sense that for the same bitrate one observed lesser quality loss for respective resolutions

Scalable Data Hiding for Online Textured 3D Terrain Visualization

International audienceA method for 3D scalable visualization, in a client/server environment is presented. The main idea presented in this paper is to increase the quality of 3D visualization for low bit rate transmission. All informations like texture, digital elevation model and projection systems are merged into a single file. The integration is achieved via data hiding whereas the scalability is realized through the multiresolution nature of JPEG2000 encoding. The embedding step is done in the lossless DWT domain. The strategy is flexible and it is up to the user to decide the level of transform of texture and DEM. In this context a comparison between various possibilities is presented by applying the method to a practical example. It is shown that a very good visualization can be realized with even a tiny fraction of the encoded coefficients

JPEG2000-Based Data Hiding and its Application to 3D Visualization

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Energy Consumption Improvement Through a Visualization Software

In the actual world frame, energy efficiency becomes a necessity. Since 1995, Kyoto protocol has highlighted that humans need to improve their energy consumption and reduce CO2 signature. Building consumption represent a third of the global energy consumption and Information Technology (IT) equipment is weighing heavily on energy expenses. For example

JPEG2000-Based Data Hiding to Synchronously Unify Disparate Facial Data for Scalable 3D Visualization

International audienceWe present a scalable encoding strategy for the 3D facial data in various bandwidth scenarios. The scalability, needed to cater diverse clients, is achieved through the multiresolution characteristic of JPEG2000. The disparate 3D facial data is synchronously unified by the application of data hiding wherein the 2.5D facial model is embedded in the corresponding 2D texture in the discrete wavelet transform (DWT) domain. The unified file conforms to the JPEG2000 standard and thus no novel format is introduced. The method is effective and has the potential to be applied in videosurveillance and videoconference applications