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Intelligent hybrid watermarking ancient-document wavelet packet decomposition-singular value decomposition-based schema

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IET IMAGE PROCESSING 2014年第12期8卷 708-717页

作者： Maatouk, Mohamed Neji Ben Amara, Najoua Essoukri Natl Engn Sch Sousse Res Unit Adv Syst Elect Engn Tunis Tunisia

The ancient documents represent one of the author's history pillars that preserve the historical events for the next generation. Many digitisation projects have been launched to preserve and to diffuse them to the public. However, ensuring security is a challenge since digital documents are susceptible to be hacked. Thus, watermarking the images of the documents seems to be a promising solution mainly for protect the copyright. Many watermarking algorithms have been proposed particularly in the medical field. However, no solution has been recommended for the images of ancient documents. In this study, the authors present a watermarking approach devoted to store images. Their algorithm is based on a wavelet packet decomposition, an intelligent choice of the best base carrier points by way of the singular value decomposition. In their approach, the insertion base and the carrier points of the signature are dynamic, varying from one image to another. For a better preservation of the watermark, they exploited a convolutional encoder to encode data. The results recorded in a set of images of ancient documents taken from the National Library of Tunisia and from the National Archives of Tunis have shown promising results.

关键词： Wavelet packets National libraries schema convolutional coder Tunisia Watermarking

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Simulation and visualization of the Viterbi decoder using a spreadsheet

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IEEE TRANSACTIONS ON EDUCATION 2003年第3期46卷 379-386页

作者： Rha, PS Univ Miami Dept Elect & Comp Engn Coral Gables FL 33124 USA

This paper demonstrates that a spreadsheet is an excellent tool for the simulation of the Viterbi decoder for educational purposes. Spreadsheet programming is streamlined by using complex number representations for metrics computation, allowing two values associated with each state at each time to be stored in a cell, thus providing a one-to-one correspondence between the spreadsheet cells and the nodes in the trellis diagram. The decoded path is plotted in a trellis diagram on the same spreadsheet so that the results can be readily visualized and examined. Either soft-decision or hard-decision decoding can be performed. A simple convolutional code of rate 1/2 and constraint length 3 is used for illustration, but the spreadsheet program, is structured in such a way that it can be readily modified to simulate other codes.

关键词： communication convolutional coder excel spreadsheet Viterbi decoder

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COMPUTATIONAL-COMPLEXITY OF SEQUENTIAL SEQUENCE ESTIMATION FOR INTERSYMBOL INTERFERENCE CHANNELS

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IEEE TRANSACTIONS ON COMMUNICATIONS 1993年第2期41卷 332-337页

作者： XIONG, FQ DAI, QY SHWEDYK, E UNIV MANITOBA DEPT ELECT ENGNWINNIPEG R3T 2N2MANITOBACANADA UNIV MANITOBA DEPT ELECT & COMP ENGNWINNIPEG R3T 2N2MANITOBACANADA

A receiver consisting of a whitened matched filter (WMF) followed by a sequential algorithm (SA) had been developed previously for intersymbol interference (ISI) channels. The channel-WMF system can be modeled as a finite-state machine (FSM). This paper presents an analysis of SA computational complexity. To determine the computational complexity, the FSM can be interpreted as a special convolutional encoder followed by a binary symbol to Q-ary symbol mapping. It follows that the computational distribution is Pareto, and that there exists a computational cutoff rate R(comp). For the uncoded data considered, the rate is fixed and the R(comp) criterion translates into a signal-to-noise ratio (SNR) criterion, i.e., for bounded computation per node, the SNR should exceed SNR(comp). An upper bound SNR(comp)' on SNR(comp) is found analytically by assuming a uniform input distribution. Arimoto's iteration equations are adapted to find the true SNR(comp) numerically.

关键词： filtration system complexity classes sequential algorithm convolutional coder matched filters finite state machines state machines Map symbols intersymbolic interference

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A convolutional autoencoder as a generative model of images for problems of distinguishing attributes and restoring images in missing regions

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JOURNAL OF OPTICAL TECHNOLOGY 2015年第8期82卷 528-532页

作者： Shcherbakov, O. V. Zhdanov, I. N. Lushin, Ya A. ITMO Univ St Petersburg Russia

This paper discusses an approach to the description of the structure of models capable of being trained to recognize representations of items of generative models-in particular, the architecture of a convolutional autoencoder is considered in detail. Reliable qualitative results of the operation of a convolutional encoder are also presented that show that it is valid to regard this model as generative because it is possible to implement output and sampling procedures, using as an example the solution of the problem of restoring images in missing regions. (C) 2015 Optical Society of America.

关键词： Valid America Output representations convolutional coder PROBLEM SOLUTION sampling of program

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Revisiting the calculation of effective free distance of turbo codes

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ELECTRONICS LETTERS 2008年第1期44卷 43-U55页

作者： Chatzigeorgiou, I. Wassell, I. J. Univ Cambridge Comp Lab Cambridge CB3 0FD England

The expression for the minimum Hamming weight of the output of a constituent convolutional encoder, when its input is a weight-2 sequence is revisited. The new expression particularly facilitates the calculation of the effective free distance of recently proposed schemes, namely non-systematic turbo codes and pseudo-randomly punctured turbo codes.

关键词： Hamming weight convolutional coder turbo codes

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XOR-FREE Implementation of convolutional Encoder for Reconfigurable Hardware

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INTERNATIONAL JOURNAL OF RECONFIGURABLE COMPUTING 2016年第1期2016卷 1-9页

作者： Purohit, Gaurav Raju, Kota Solomon Chaubey, Vinod Kumar BITS Pilani Dept EEE Pilani 333031 Rajasthan India Cent Elect Engn Res Inst Digital Syst Grp Pilani 333031 Rajasthan India

This paper presents a novel XOR-FREE algorithm to implement the convolutional encoder using reconfigurable hardware. The approach completely removes theXORprocessing of a chosen nonsystematic, feedforward generator polynomial of larger constraint length. The hardware (HW) implementation of new architecture uses Lookup Table (LUT) for storing the parity bits. The design implements architectural reconfigurability by modifying the generator polynomial of the same constraint length and code rate to reduce the design complexity. The proposed architecture reduces the dynamic power up to 30% and improves the hardware cost and propagation delay up to 20% and 32%, respectively. The performance of the proposed architecture is validated in MATLAB Simulink and tested on Zynq-7 series FPGA.

关键词： new buildings convolutional coder constraint length reconfigurable hardware code rate generator polynomial Propagation delay

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convolutional codes over integer rings suitable for parallel and serial concatenation

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ELECTRONICS LETTERS 2003年第9期39卷 726-727页

作者： Berkmann, J Infineon Technol AG D-81669 Munich Germany

Choosing a convolutional encoder over a ring with feedback may not lead to a suitable component code for parallel or serial concatenation. A simple criterion is derived that allows to check whether a rational encoding matrix generating some convolutional code over the integer ring Z(pm) (p prime) has exclusively infinite impulse responses.

关键词： Parallel Lines encoding matrix Feedback convolutional coder IMPULSE RESPONSE convolutional coding Integer

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On the Equivalence of TCM Encoders

On the Equivalence of TCM Encoders

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IEEE International Symposium on Information Theory

作者： Alvarado, Alex Graell i Amat, Alexandre Brannstrom, Fredrik Agrell, Erik Univ Cambridge Dept Engn Cambridge CB2 1TN England Chalmers Dept Signals & Syst Gothenburg Sweden

ISBN: (纸本)9781467325790

Optimal trellis-coded modulation (TCM) schemes are obtained by jointly designing the convolutional encoder and the binary labeling of the constellation. Unfortunately this approach is infeasible for large encoder memories or constellation sizes. Traditional TCM designs circumvent this problem by using a labeling that follows the set-partitioning principle and by performing an exhaustive search over the encoders. Therefore, traditional TCM schemes are not necessarily optimal. In this paper, we study binary labelings for TCM and show how they can be grouped into classes, which considerably reduces the search space in a joint design. For the particular case of 8-ary modulation the search space for the labelings is reduced from 8! to 240. Using this classification, we formally prove that for any channel it is always possible to design a TCM system based on the binary-reflected Gray code with identical performance to the one proposed by Ungerboeck in 1982. Moreover, the classification is used to tabulate asymptotically optimal TCM schemes.

关键词： ENcoder equivalence convolutional coder CONSTELLATIONS exhaustive search

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Age Progression/Regression by Conditional Adversarial Autoencoder 30

Age Progression/Regression by Conditional Adversarial Autoen...

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30th IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)

作者： Zhang, Zhifei Song, Yang Qi, Hairong Univ Tennessee Knoxville TN 37996 USA

ISBN: (纸本)9781538604571

"If I provide you a face image of mine (without telling you the actual age when I took the picture) and a large amount of face images that I crawled (containing labeled faces of different ages but not necessarily paired), can you show me what I would look like when I am 80 or what I was like when I was 5?" The answer is probably a " No." Most existing face aging works attempt to learn the transformation between age groups and thus would require the paired samples as well as the labeled query image. In this paper, we look at the problem from a generative modeling perspective such that no paired samples is required. In addition, given an unlabeled image, the generative model can directly produce the image with desired age attribute. We propose a conditional adversarial autoencoder (CAAE) that learns a face manifold, traversing on which smooth age progression and regression can be realized simultaneously. In CAAE, the face is first mapped to a latent vector through a convolutional encoder, and then the vector is projected to the face manifold conditional on age through a deconvolutional generator. The latent vector preserves personalized face features (i.e., personality) and the age condition controls progression vs. regression. Two adversarial networks are imposed on the encoder and generator, respectively, forcing to generate more photo-realistic faces. Experimental results demonstrate the appealing performance and flexibility of the proposed framework by comparing with the state-of-the-art and ground truth.

关键词： Face Manifolds Aging Gallium nitride Generators Training Biological system modeling Face Face Biological system modeling Manifolds dynamos gallium nitrides Aging Functional training images aging condition iodine convolutional coder Conditional Imagery (Psychotherapy) Absolute age

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Robust encoded spread spectrum image watermarking in contourlet domain

Robust encoded spread spectrum image watermarking in contour...

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International Conference on Signal Processing and Communication Systems, ICSPCS

作者： F. Garcia-Ugalde M. Cedillo-Hernandez E. Morales-Delgado B. Psenicka Facultad de Ingeniería División de Ingeniería Eléctrica Universidad Nacional Autónoma de México Mexico Distrito Federal Mexico

ISBN: (纸本)9781467323925

This paper presents a new robust watermarking system for digital images. The main challenge in every watermarking algorithm is to create a high capable, robust and imperceptible scheme. Unlike other watermarking methods, our system encodes the watermark using a convolutional encoder and embeds the encoded watermark in the transform domain of an image using a direct sequence spread spectrum technique to accomplish a high robustness. The embedded watermark bits are retrieved computing the correlation between the watermarked coefficients and the pseudorandom sequences used in the watermark embedding. In addition, the retrieved bits are decoded using the Viterbi algorithm to recover the hidden watermark. A low perceptibility of the watermark on the host image is preferred, therefore, some features of the human visual system are considered for achieving a high perceptual quality of the watermarked image. For assessing such quality, a structural similarity index measure is adopted. Our watermarking algorithm is robust to common image processes in the spatial domain.

关键词： Digital watermarking copyright protection contourlet domain convolutional encoder cropping. convolutional coder Watermarking Digital watermarking crop enterprises PSEUDORANDOM SEQUENCES Robustness Viterbi algorithm Imagery (Psychotherapy) images digital image watermarking direct sequence spread spectrum

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