With digital equipment becoming increasingly networked, either on wired or wireless networks, for personal and professional use alike, distributed software systems have become a crucial element in information and communications technologies. The study of these systems forms the core of the ARLES' work, which is specifically concerned with defining new system software architectures, based on the use of emerging networking technologies. In this context, we concentrate on the study of distributed systems which bring to life the vision of ubiquitous computing systems, also known as ambient intelligence.

반도체 공정 overview

National Institute of Standards and Technology における超伝導研究及び生活

A novel reversible data hiding algorithm, which can recover the original image without any distortion from the marked image after the hidden data have been extracted, is presented in this paper. This algorithm utilizes the zero or the minimum points of the histogram of an image and slightly modifies the pixel grayscale values to embed data into the image. It can embed more data than many of the existing reversible data hiding algorithms. It is proved analytically and shown experimentally that the peak signal-to-noise ratio (PSNR) of the marked image generated by this method versus the original image is guaranteed to be above 48 dB. This lower bound of PSNR is much higher than that of all reversible data hiding techniques reported in the literature. The computational complexity of our proposed technique is low and the execution time is short. The algorithm has been successfully applied to a wide range of images, including commonly used images, medical images, texture images, aerial images and all of the 1096 images in CorelDraw database. Experimental results and performance comparison with other reversible data hiding schemes are presented to demonstrate the validity of the proposed algorithm.

Reversible data hiding

A morphable model for the synthesis of 3D faces

Multimedia watermarking technology has evolved very quickly during the last few years. A digital watermark is information that is imperceptibly and robustly embedded in the host data such that it cannot be removed. A watermark typically contains information about the origin, status, or recipient of the host data. In this tutorial paper, the requirements and applications for watermarking are reviewed. Applications include copyright protection, data monitoring, and data tracking. The basic concepts of watermarking systems are outlined and illustrated with proposed watermarking methods for images, video, audio, text documents, and other media. Robustness and security aspects are discussed in detail. Finally, a few remarks are made about the state of the art and possible future developments in watermarking technology.

http://www.frank-hartung.com/publications/ProcIEEEHartungKutter.pdf

Multimedia watermarking techniques

We present a high capacity reversible watermarking scheme using companding technique over integer DCT
coefficients of image blocks. This scheme takes advantage of integer DCT coefficients' Laplacian-shape-like
distribution, which permits low distortion between the watermarked image and the original one caused by the bit-shift
operations of the companding technique in the embedding process.
In our scheme, we choose AC coefficients in the integer DCT domain for the bit-shift operation, and therefore the
capacity and the quality of the watermarked image can be adjusted by selecting different numbers of coefficients of
different frequencies. To prevent overflows and underflows in the spatial domain caused by modification of the DCT
coefficients, we design a block discrimination structure to find suitable blocks that can be used for embedding without
overflow or underflow problems. We can also use this block discrimination structure to embed an overhead of location
information of all blocks suitable for embedding. With this scheme, watermark bits can be embedded in the saved LSBs
of coefficient blocks, and retrieved correctly during extraction, while the original image can be restored perfectly.

Integer DCT-based reversible watermarking for images using companding technique

Digital watermarking has been increasingly applied to hide information in digital multimedia data, thus enlisting the watermarking technology in the difficult fight against intellectual property rights infringement. The authors have developed a secure, robust watermarking algorithm and applied it in digital streaming MPEG-2 format video-the format of choice in the broadcast and video stock industry.

/pdf/digital-watermarking-from-concepts-to-real-time-video-4f3ft1ej1e.pdf

Digital watermarking: from concepts to real-time video applications

A variety of widely accepted and efficient compression methods do exist for still images. To name a few, there are standardised schemes like JPEG and JPEG2000 which are well suited for photorealistic true colour and grey scale images and usually operated in lossy mode to achieve high compression ratios. These schemes are well suited for images that are processed within face recognition systems. In the case of forensic biometric systems, compression of fingerprint images has already been applied in automatic fingerprint identification systems (AFIS) applications, where the size of the digital fingerprint archives would be tremendous for uncompressed images. In these large scale applications wavelet scalar quantization has a long tradition as an effective encoding scheme. This paper gives an overview of the study BioCompress that has been conducted at Fraunhofer IGD on behalf of the Federal Office for Information Security (BSI). Based on fingerprint and face image databases and different biometric algorithms we evaluated the impact of lossy compression algorithms on the recognition performance of biometric recognition systems.

Evaluation of image compression algorithms for fingerprint and face recognition systems

We present an automatic face recognition approach, which relies on the analysis of the three-dimensional facial surface. The proposed approach consists of two basic steps, namely a precise fully automatic normalization stage followed by a histogram-based feature extraction algorithm. During normalization the tip and the root of the nose are detected and the symmetry axis of the face is determined using a PCA analysis and curvature calculations. Subsequently, the face is realigned in a coordinate system derived from the nose tip and the symmetry axis, resulting in a normalized 3D model. The actual region of the face to be analyzed is determined using a simple statistical method. This area is split into disjoint horizontal subareas and the distribution of depth values in each subarea is exploited to characterize the face surface of an individual. Our analysis of the depth value distribution is based on a straightforward histogram analysis of each subarea. When comparing the feature vectors resulting from the histogram analysis we apply three different similarity metrics. The proposed algorithm has been tested with the FRGC v2 database, which consists of 4950 range images. Our results indicate that the city block metric provides the best classification results with our feature vectors. The recognition system achieved an equal error rate of 5.89% with correctly normalized face models.

A 3D face recognition algorithm using histogram-based features

In this paper, benchmarking results of watermarking techniques are presented. The benchmark includes evaluation of the watermark robustness and the subjective visual image quality. Four different algorithms are compared, and exhaustively tested. One goal of these tests is to evaluate the feasibility of a Common Functional Model (CFM) developed in the European Project OCTALIS and determine parameters of this model, such as the length of one watermark. This model solves the problem of image trading over an insecure network, such as Internet, and employs hybrid watermarking. Another goal is to evaluate the resistance of the watermarking techniques when subjected to a set of attacks. Results show that the tested techniques do not have the same behavior and that no tested methods has optimal characteristics. A last conclusion is that, as for the evaluation of compression techniques, clear guidelines are necessary to evaluate and compare watermarking techniques.

Wolfgang Funk

Papers

Integer DCT-based reversible watermarking for images using companding technique

Digital watermarking: from concepts to real-time video applications

Evaluation of image compression algorithms for fingerprint and face recognition systems

A 3D face recognition algorithm using histogram-based features

OCTALIS benchmarking : comparison of four watermarking techniques