Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028170
N. Karayiannis, J. Chookiarti
This paper presents adaptive multiuser CDMA detection techniques for wireless communication systems. Directly estimated adaptive (DEA) detectors are developed by formulating multiuser CDMA detection as an inverse problem in the presence of channel-induced interference and noise. The estimation of the detector parameters is accomplished using elements of regularization theory. The regularized solutions are computed by an adaptive algorithm that can be implemented on-line.
{"title":"Directly estimated multiuser detectors for code-division multiple-access signals and their adaptive implementation","authors":"N. Karayiannis, J. Chookiarti","doi":"10.1109/ICDSP.2002.1028170","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028170","url":null,"abstract":"This paper presents adaptive multiuser CDMA detection techniques for wireless communication systems. Directly estimated adaptive (DEA) detectors are developed by formulating multiuser CDMA detection as an inverse problem in the presence of channel-induced interference and noise. The estimation of the detector parameters is accomplished using elements of regularization theory. The regularized solutions are computed by an adaptive algorithm that can be implemented on-line.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127674719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028182
I. Grinias, G. Tziritas
We propose a method for estimating the motion parameters for a rotating camera with a possibly changing focal length. This method is suitable for analysing sport event videos. The estimation process consists of three stages: (1) robust estimation of the 2D translational components; (2) 2D block-based motion estimation; (3) robust estimation of a parametric motion model. For more reliability, confidence measures for the 2D motion vectors are introduced. The reliability of the method is illustrated on some difficult real image sequences.
{"title":"Robust pan, tilt and zoom estimation","authors":"I. Grinias, G. Tziritas","doi":"10.1109/ICDSP.2002.1028182","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028182","url":null,"abstract":"We propose a method for estimating the motion parameters for a rotating camera with a possibly changing focal length. This method is suitable for analysing sport event videos. The estimation process consists of three stages: (1) robust estimation of the 2D translational components; (2) 2D block-based motion estimation; (3) robust estimation of a parametric motion model. For more reliability, confidence measures for the 2D motion vectors are introduced. The reliability of the method is illustrated on some difficult real image sequences.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121426005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028340
A. Dziech, B. Tibken, P. Slusarczyk
In this paper an image data compression scheme based on the periodic Haar piecewise-linear (PHL) transform and quantization tables is proposed. Effectiveness of the compression for different classes of images is evaluated. The comparison of the compression quality using PHL and DCT transforms is given.
{"title":"Image compression using periodic Haar piecewise-linear PHL transform","authors":"A. Dziech, B. Tibken, P. Slusarczyk","doi":"10.1109/ICDSP.2002.1028340","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028340","url":null,"abstract":"In this paper an image data compression scheme based on the periodic Haar piecewise-linear (PHL) transform and quantization tables is proposed. Effectiveness of the compression for different classes of images is evaluated. The comparison of the compression quality using PHL and DCT transforms is given.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129290358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028173
D. Darsena, G. Gelli, L. Paura, L. Verdoliva
This paper deals with the performance assessment of receivers employing linear conjugate-linear (LCL) periodically time-varying (PTV) filters, proposed to suppress narrowband interference (NBI) in code-division multiple-access (CDMA) overlay systems. The bit-error-rate (BER) at the output of the matched-filter receiver is evaluated analytically, by resorting to the standard Gaussian approximation. The comparison with Monte Carlo simulation results validates the analysis over a wide range of signal-to-noise ratio and signal-to-interference ratio values.
{"title":"Performance analysis of LCL-PTV narrowband interference suppression algorithms","authors":"D. Darsena, G. Gelli, L. Paura, L. Verdoliva","doi":"10.1109/ICDSP.2002.1028173","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028173","url":null,"abstract":"This paper deals with the performance assessment of receivers employing linear conjugate-linear (LCL) periodically time-varying (PTV) filters, proposed to suppress narrowband interference (NBI) in code-division multiple-access (CDMA) overlay systems. The bit-error-rate (BER) at the output of the matched-filter receiver is evaluated analytically, by resorting to the standard Gaussian approximation. The comparison with Monte Carlo simulation results validates the analysis over a wide range of signal-to-noise ratio and signal-to-interference ratio values.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117029650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028195
I. Kostopoulos, S. Gilani, A. Skodras
In the paper an approach for digital image authentication is described. The authentication process is achieved by means of a watermarking scheme that embeds an approximation of the image into itself. Specifically, the luminance of the image is inserted into the three colour channels, using a mapping function. The embedding process is implemented using a secret key k that maps the position of the pixel, where the luminance information is taken from, to the position of the pixel in which the watermark information is embedded. The quality of the watermarked images remains very high both subjectively and objectively. The proposed approach belongs to the category of semi-fragile techniques used for image authentication.
{"title":"Colour image authentication based on a self-embedding technique","authors":"I. Kostopoulos, S. Gilani, A. Skodras","doi":"10.1109/ICDSP.2002.1028195","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028195","url":null,"abstract":"In the paper an approach for digital image authentication is described. The authentication process is achieved by means of a watermarking scheme that embeds an approximation of the image into itself. Specifically, the luminance of the image is inserted into the three colour channels, using a mapping function. The embedding process is implemented using a secret key k that maps the position of the pixel, where the luminance information is taken from, to the position of the pixel in which the watermark information is embedded. The quality of the watermarked images remains very high both subjectively and objectively. The proposed approach belongs to the category of semi-fragile techniques used for image authentication.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114859771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028196
V. Ruiz
This paper presents the theoretical development of a nonlinear adaptive filter based on a concept of filtering by approximated densities (FAD). The most common procedures for nonlinear estimation apply the extended Kalman filter. As opposed to conventional techniques the proposed recursive algorithm does not require any linearisation. The prediction uses a maximum entropy subject to constraints. Thus, the densities created are of an exponential type and depend on a finite number of parameters. The filtering yields recursive equations involving these parameters. The update applies the Bayes' theorem. Through simulation on a generic exponential model, the proposed nonlinear filter proves to be superior to the extended Kalman filter and a class of nonlinear filters based on the partitioning algorithm.
{"title":"An efficient approach to highly non-linear estimation","authors":"V. Ruiz","doi":"10.1109/ICDSP.2002.1028196","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028196","url":null,"abstract":"This paper presents the theoretical development of a nonlinear adaptive filter based on a concept of filtering by approximated densities (FAD). The most common procedures for nonlinear estimation apply the extended Kalman filter. As opposed to conventional techniques the proposed recursive algorithm does not require any linearisation. The prediction uses a maximum entropy subject to constraints. Thus, the densities created are of an exponential type and depend on a finite number of parameters. The filtering yields recursive equations involving these parameters. The update applies the Bayes' theorem. Through simulation on a generic exponential model, the proposed nonlinear filter proves to be superior to the extended Kalman filter and a class of nonlinear filters based on the partitioning algorithm.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127165768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028155
N. Doulamis, A. Doulamis, K. Ntalianis
An adaptive neural network architecture is proposed for efficient video object segmentation and tracking of stereoscopic video sequences. The scheme includes (a) a retraining algorithm for adapting network weights to current conditions; (b) a semantically meaningful object extraction module for creating a retraining set; (c) a decision mechanism, which detects the time instances of a new network retraining. The retraining algorithm optimally adapts network weights by exploiting information of the current conditions and simultaneously minimally degrading the obtained network knowledge. The algorithm results in the minimization of a convex function subject to linear constraints, thus, one minimum exists. Furthermore, a decision mechanism is included to detect the time instances that a new network retraining is required. A description of the current conditions is provided by a segmentation fusion algorithm, which appropriately combines color and depth information.
{"title":"Adaptive classification-based articulation and tracking of video objects employing neural network retraining","authors":"N. Doulamis, A. Doulamis, K. Ntalianis","doi":"10.1109/ICDSP.2002.1028155","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028155","url":null,"abstract":"An adaptive neural network architecture is proposed for efficient video object segmentation and tracking of stereoscopic video sequences. The scheme includes (a) a retraining algorithm for adapting network weights to current conditions; (b) a semantically meaningful object extraction module for creating a retraining set; (c) a decision mechanism, which detects the time instances of a new network retraining. The retraining algorithm optimally adapts network weights by exploiting information of the current conditions and simultaneously minimally degrading the obtained network knowledge. The algorithm results in the minimization of a convex function subject to linear constraints, thus, one minimum exists. Furthermore, a decision mechanism is included to detect the time instances that a new network retraining is required. A description of the current conditions is provided by a segmentation fusion algorithm, which appropriately combines color and depth information.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127210061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028233
H. Own, A. Hassanien
This paper presents a registration algorithm with a new approach for automatic control point selection within a wavelet transform of astronomical images. It simply looks at the evolution of the coefficients across the different scales and extracts more significant points according to its contribution weight to the multiresolution local contrast entropy. In the proposed algorithm mutual information is applied as a similarity measure to get the best matching between extracted control points. A wavelet multiresolution approach is used to accelerate the matching process while maintaining the accuracy of mutual information. The proposed algorithm has been applied on single sensor astronomical data. The result shows that the algorithm improves computational efficiency and yields robust and consistent image registration results.
{"title":"Multiresolution image registration algorithm in wavelet transform domain","authors":"H. Own, A. Hassanien","doi":"10.1109/ICDSP.2002.1028233","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028233","url":null,"abstract":"This paper presents a registration algorithm with a new approach for automatic control point selection within a wavelet transform of astronomical images. It simply looks at the evolution of the coefficients across the different scales and extracts more significant points according to its contribution weight to the multiresolution local contrast entropy. In the proposed algorithm mutual information is applied as a similarity measure to get the best matching between extracted control points. A wavelet multiresolution approach is used to accelerate the matching process while maintaining the accuracy of mutual information. The proposed algorithm has been applied on single sensor astronomical data. The result shows that the algorithm improves computational efficiency and yields robust and consistent image registration results.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127549005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028329
Y. Wen, S. Chan, K. Ho
Subspace tracking is an efficient method to reduce the complexity in estimating the signal subspace required in subspace-based multiuser detection algorithm. Recursive least square (RLS)-based subspace tracking algorithms such as the PAST algorithm can be used to estimate the signal subspace adaptively with relatively low computational complexity. However, it is shown in this paper that subspace estimation using conventional autocorrelation matrix is very sensitive to impulse noise. A new robust correlation matrix, based on robust statistics, is proposed to overcome this problem. Moreover, a new robust PAST algorithm is developed, again using robust statistics, for robust subspace tracking. A new restoring mechanism is also proposed to handle long bursts of impulses, which sporadically occur in communications systems. Simulation results show that the proposed robust subspace tracking-based blind multiuser detector performs better than the conventional approach, especially under consecutive impulses. The adaptation of the proposed scheme in a dynamic multiple access channel, where users may enter and exit the shared mobile channel, is also found to be satisfactory.
{"title":"A robust subspace tracking algorithm for subspace-based blind multiuser detection in impulsive noise","authors":"Y. Wen, S. Chan, K. Ho","doi":"10.1109/ICDSP.2002.1028329","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028329","url":null,"abstract":"Subspace tracking is an efficient method to reduce the complexity in estimating the signal subspace required in subspace-based multiuser detection algorithm. Recursive least square (RLS)-based subspace tracking algorithms such as the PAST algorithm can be used to estimate the signal subspace adaptively with relatively low computational complexity. However, it is shown in this paper that subspace estimation using conventional autocorrelation matrix is very sensitive to impulse noise. A new robust correlation matrix, based on robust statistics, is proposed to overcome this problem. Moreover, a new robust PAST algorithm is developed, again using robust statistics, for robust subspace tracking. A new restoring mechanism is also proposed to handle long bursts of impulses, which sporadically occur in communications systems. Simulation results show that the proposed robust subspace tracking-based blind multiuser detector performs better than the conventional approach, especially under consecutive impulses. The adaptation of the proposed scheme in a dynamic multiple access channel, where users may enter and exit the shared mobile channel, is also found to be satisfactory.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127561467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/ICDSP.2002.1028181
J. Condell, B. Scotney, P. Morrow
A Galerkin finite element approach is described for computing optical flow which uses an adaptive triangular mesh in which the resolution increases where motion is found to occur. The mesh facilitates a reduction in computational effort by enabling processing to focus on particular objects of interest in a scene, specifically those areas where motion is detected. The method is applied to real image sequences where a significant part of the image is static.
{"title":"Detection and estimation of motion using adaptive grids","authors":"J. Condell, B. Scotney, P. Morrow","doi":"10.1109/ICDSP.2002.1028181","DOIUrl":"https://doi.org/10.1109/ICDSP.2002.1028181","url":null,"abstract":"A Galerkin finite element approach is described for computing optical flow which uses an adaptive triangular mesh in which the resolution increases where motion is found to occur. The mesh facilitates a reduction in computational effort by enabling processing to focus on particular objects of interest in a scene, specifically those areas where motion is detected. The method is applied to real image sequences where a significant part of the image is static.","PeriodicalId":351073,"journal":{"name":"2002 14th International Conference on Digital Signal Processing Proceedings. DSP 2002 (Cat. No.02TH8628)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126205539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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