Showing papers in "Signal Processing in 1998"

TL;DR: The proposed method is robust and of much lower complexity than a complete decoding process followed by watermarking in the pixel domain and re-encoding, and is also applicable to other hybrid transform coding schemes like MPEG-1, MPEG-4, H.263.

TL;DR: In this paper, a Fourier-Mellin-based approach is used to construct watermarks which are designed to be unaffected by any combination of rotation and scale transformations, and a novel method of CDMA spread spectrum encoding is introduced which allows one to embed watermark messages of arbitrary length and which need only a secret key for decoding.

TL;DR: A new watermarking algorithm is presented: the method, which operates in the frequency domain, embeds a pseudo-random sequence of real numbers in a selected set of DCT coefficients, which is adapted to the image by exploiting the masking characteristics of the human visual system, thus ensuring the watermark invisibility.

TL;DR: This paper generalizes the GVF formulation to include two spatially varying weighting functions, which improves active contour convergence to long, thin boundary indentations, while maintaining other desirable properties of GVf, such as an extended capture range.

TL;DR: A copyright protection method that is based on hiding an ‘invisible’ signal, known as digital watermark, in the image is presented and a variation that generates image dependent watermarks as well as a method to handle geometrical distortions are presented.

TL;DR: This work presents a watermarking procedure to embed copyright protection into digital audio by directly modifying the audio samples and introduces the notion of a dual watermark: one which uses the original signal during detection and one which does not.

TL;DR: A review of perceptual image quality metrics and their application to still image compression can be found in this article, where a broad range of metrics ranging from simple mathematical measures to those which incorporate full perceptual models are examined.

TL;DR: This paper presents a comprehensive analysis and classification of the numerous coding artifacts which are introduced into the reconstructed video sequence through the use of the hybrid MC/DPCM/DCT video coding algorithm.

TL;DR: This paper categorizes the various active contour systems according to the definition of the deformable model, and presents in detail one particular formulation for deformable templates which combines edge, texture, color and region information for the external energy and model deformations using wavelets, splines or Fourier descriptors.

TL;DR: It is shown that in fact, ICA can be performed by very simple Hebbian or anti-Hebbian learning rules, which may have only weak relations to such information-theoretical quantities.

TL;DR: This task may be accomplished at the coder site to support the functionalities foreseen by new multimedia scenarios, and in particular the content-based functionalities focused by the MPEG-4 activity, allowing the user to access and decode single objects of a video sequence.

TL;DR: A Viterbi search-based dual active contour algorithm is able to overcome many of the problems of initialisation and minimisation and achieve over 99% accurate segmentation on a database of 20 130 Pap stained cell images.

TL;DR: This paper presents an additive watermarking technique for grey-scale pictures that consists in secretly embedding copyright information (a binary code) into the picture without degrading its quality through the phase of maximal length sequences (MLS).

TL;DR: It is demonstrated, through both a statistical study and some computer simulations, that the proposed method has a much reduced noise sensitivity with respect to the linear unsharp masking technique and it permits to obtain perceptually pleasant results.

TL;DR: A two-layer perceptron is used as a de-mixing system to separate sources in non-linear mixture to derive the learning equations for the hidden layer.

TL;DR: An algorithm for automatic, noise robust 2D shape estimation of moving objects in video sequences is presented, which considers a moving camera, and the resulting object shapes look subjectively much better than those from the reference algorithm.

TL;DR: It is suggested that the next step in improving color image fidelity metrics is to redefine color difference formula such as CIELAB Δ E 94 in terms of local contrast.

TL;DR: This model has been able to mimic quite accurately the temporally varying subjective picture quality of video sequences as recorded by the ITU-R SSCQE method.

TL;DR: A method for optimizing the echo times in order to maximize the signal-to-noise ratio (SNR) in the resulting R 2 image for both methods and for both fitting algorithms is presented.

TL;DR: An algorithm for combined acoustic echo control and noise reduction that consists of a (conventional) echo canceller and an additional noise and residual echo reduction filter and a special feature of the algorithm is the procedure for estimating the residual echo power spectral density.

TL;DR: This paper develops a 2D DFRFT which can preserve the rotation properties and provide similar results to continuous FRFT.

TL;DR: In this paper, the authors make use of a matched filter bank (MAFI) approach to derive spectral estimators for stationary signals with mixed spectra, and they show that the Capon spectral estimator as well as the more recently recently proposed CCA estimator can be computed using the same approach.

TL;DR: An original motion segmentation algorithm based on 2D polynomial motion models, a multiresolution robust estimator to compute these motion model models, and appropriate local observations supplying both motion relevant information and their reliability are presented.

TL;DR: This paper describes a blind demodulator design which has proven practical, and illustrates several implementations of the design, and closes with a list of open theoretical questions, which, if answered, can lead to the next generation ofblind demodulators.

TL;DR: This work shows that applying a global transformation on a surface template, is equivalent to applying certain global forces on a deformable model, and proposes a scheme which combines the registration and free-form deformation, which allows us to control the amount of deformation from the reference shape with a single parameter.

TL;DR: Both moment and cumulant fourth-order TV-HOS, referred to as the Wigner-Ville trispectra are shown to be superior to the second-order methods for this application and are demonstrated in the context of FM signals affected by multiplier noise.

TL;DR: This paper proposes a general merging algorithm that can be used to create new connected operators (in particular self-dual operators) and efficient segmentation algorithms (robust criteria and efficient implementation).

TL;DR: This work proposes the application of two filterbanks with bark-scaled frequency bands: a discrete wavelet transformation and a nonuniform polyphase filterbank, and their enhancement results as well as their expenditures are compared to each other and to those obtained with uniform spectral transformations.

TL;DR: The use of Wiener filtering to simultaneously reduce all the perturbations at the sound pick-up of hands-free terminals is investigated and the use of psychoacoustic properties is also considered in order to improve the quality of the transmitted speech signals.

TL;DR: In this paper, a variable selection method based on stochastic exploration of the input space referring to the input variables neighborhood is presented, where the ANN structure properly instructed to perform the required mapping, had been submitted to the known input variables, but contaminated with noise to reduce the initial number of used variables through the determination of the relevancy of each variable initially used.