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2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.最新文献

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Planar homography from Fourier domain representation 傅里叶域表示的平面单应性
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458522
M.P. Kumar, S. Kuthirummal, C. V. Jawahar, P J Narayanan
{"title":"Planar homography from Fourier domain representation","authors":"M.P. Kumar, S. Kuthirummal, C. V. Jawahar, P J Narayanan","doi":"10.1109/SPCOM.2004.1458522","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458522","url":null,"abstract":"Computing the transformation between two views of a planar scene is an important step in many computer vision applications. Spatial approaches to solve this problem need corresponding sets of primitives-points, lines, conies, etc. Identification of corresponding primitives in two images is non-trivial, limiting the applicability of such approaches. In this paper, we present a novel Fourier domain based approach that makes use of image intensities for computing the image-to-image transformation. Our approach transforms the images to the Fourier domain and then represents them in a coordinate system in which the affine transformation is reduced to an anisotropic scaling. The anisotropic scale factors can be computed using cross correlation methods, and working backwards from this, we compute the entire transformation. It does not require any correspondences thereby making it practically very useful. Applications to registration and recognition are discussed.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116684004","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}
引用次数: 17
Comparison of clustered and antenna interleaving OFDM in multiple-antenna systems with amplifier nonlinearities 放大器非线性多天线系统中集群OFDM与天线交错OFDM的比较
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458367
F. Gregorio, T. Laakso, R. Wichman
{"title":"Comparison of clustered and antenna interleaving OFDM in multiple-antenna systems with amplifier nonlinearities","authors":"F. Gregorio, T. Laakso, R. Wichman","doi":"10.1109/SPCOM.2004.1458367","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458367","url":null,"abstract":"The transmit power requirements are one of the key issues in future wireless orthogonal frequency division multiplexing (OFDM) systems. Diversity techniques applied in OFDM systems help to reduce nonlinear effects produced by the power amplifier. In this paper, low peak to average power ratio (PAPR) techniques clustered OFDM (COFDM) and antenna interleaving OFDM (AIOFDM) applied in a wireless LAN systems are evaluated under nonlinear power amplifier. This paper shows that the bit error rate (BER) obtained using antenna interleaving OFDM is lower compared to the BER obtained applying clustered OFDM and conventional OFDM in fading channels subject to amplifier nonlinearities. The implementation of these low PAPR techniques can help to reduce the power amplifier linearity restrictions increasing the power efficiency. Power amplifier efficiency is crucial in mobile systems since it has a dominant effect on the battery charge life.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116693942","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}
引用次数: 5
Performance evaluation of space-time coded OFDM systems employing cyclic prefix estimation techniques 基于循环前缀估计技术的空时编码OFDM系统性能评价
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458381
V. K. Shrivastava, D. K. Mehra
{"title":"Performance evaluation of space-time coded OFDM systems employing cyclic prefix estimation techniques","authors":"V. K. Shrivastava, D. K. Mehra","doi":"10.1109/SPCOM.2004.1458381","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458381","url":null,"abstract":"Space-time coding (STC) offers an effective transmit-antenna diversity technique to combat fading. On the other hand, the orthogonal frequency division multiplexing (OFDM) technique transforms a frequency-selective fading channel into parallel correlated fading channels. Hence, in the presence of frequency selectivity, it is natural to combine STC with the OFDM systems. The channel state information is an essential requirement in the case of ST OFDM systems. In this paper, a unique channel estimation technique for MIMO OFDM systems exploiting the cyclic prefix of OFDM symbols has been proposed. The performance of the ST coded OFDM systems have been evaluated for realistic channel conditions.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117139091","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}
引用次数: 0
BER performance improvement of an FNN based equaliser using fuzzy tuned sigmoidal activation function 利用模糊调谐s型激活函数改进基于FNN的均衡器误码率性能
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458504
J. Satapathy, S. Das
{"title":"BER performance improvement of an FNN based equaliser using fuzzy tuned sigmoidal activation function","authors":"J. Satapathy, S. Das","doi":"10.1109/SPCOM.2004.1458504","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458504","url":null,"abstract":"Adaptive equalisers are characterised in general by their structures, the learning algorithms and the use of training sequences. This paper presents a novel technique of improving the performance of conventional multilayer perceptron (MLP) based decision feedback equaliser (DFE) of reduced structural complexity by adapting the slope of the sigmoidal activation function using fuzzy logic control technique. The adaptation of the slope parameter increases the degrees of freedom in the weight space of the conventional feedforward neural network (CFNN) configuration. Application of this technique reduces the structural complexity of a conventional FNN equaliser, provides faster learning and significant performance gain.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115663777","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}
引用次数: 1
improved Bayesian estimation of weak signals in non-Gaussian noise by optimal quantization 通过最优量化改进非高斯噪声中弱信号的贝叶斯估计
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458412
P. R. Bhat, D. Rousseau, G. V. Anand
{"title":"improved Bayesian estimation of weak signals in non-Gaussian noise by optimal quantization","authors":"P. R. Bhat, D. Rousseau, G. V. Anand","doi":"10.1109/SPCOM.2004.1458412","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458412","url":null,"abstract":"In this paper, we present a new improved method for signal shape estimation in non-Gaussian noise with low signal to noise ratio. We combine a nonlinear preprocessing with Wiener filtering. In the proposed method, the data received is first quantized by a symmetric 3-level quantizer before processing by the Wiener filter. A complete theoretical analysis of this quantizer-estimator is worked out under low signal to noise ratio conditions. In this framework, we show that if the noise is sufficiently non-Gaussian and the quantizer thresholds are optimally chosen, the quantization, although limited to 3-levels, leads to an enhancement of the estimation performed by the Wiener filter. Numerical results comparing the quantizer-estimator with the Wiener filter applied alone are presented to confirm the theory. Non-Gaussian noise distributions specifically relevant for an underwater acoustic environment are chosen for illustration.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127129319","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}
引用次数: 0
Harmonic mean of squared product distances: a new criterion to design codes for independent fading channels 平方积距离的谐波平均值:设计独立衰落信道码的新准则
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458512
R. Deepak, K. Hari
{"title":"Harmonic mean of squared product distances: a new criterion to design codes for independent fading channels","authors":"R. Deepak, K. Hari","doi":"10.1109/SPCOM.2004.1458512","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458512","url":null,"abstract":"A new performance criterion which is called harmonic mean of squared product distances (HMSPD) to design codes for an independent fading channel is proposed. The bound on symbol error probability due to HMSPD criterion is shown to be tighter than the one due to the popular minimum product distance (MPD) criterion. HMSPD criterion is applied to obtain the optimum pre-rotating matrices for a BPSK transmission over a fast fading channel. The optimum 2/spl times/2 pre-rotating matrix is derived analytically and a new ad-hoc method is proposed to do numerical optimization for rotation matrices of higher dimensions. The BER performance of the codes designed using them is compared with that of the one designed based on the MPD criterion. The HMSPD criterion gives a slightly better performance.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127407409","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}
引用次数: 1
Real time visual control of two-axis robotic arm using motion estimation 基于运动估计的二轴机械臂实时视觉控制
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458404
C. Mohan, M.V. Badhrinarayanan, R. Janarthanan
{"title":"Real time visual control of two-axis robotic arm using motion estimation","authors":"C. Mohan, M.V. Badhrinarayanan, R. Janarthanan","doi":"10.1109/SPCOM.2004.1458404","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458404","url":null,"abstract":"Visual servoing is the fusion of results from many elemental areas including high speed image processing, kinematics, dynamics, control system, and real-time computing. This paper presents the use of vision to control a two-axis robotic arm with active tracking of the probe. On specifying the target position in image coordinates, a suitable linear/non-linear mapping is used to transform it to real world coordinates. This is changed to joint level inputs and given to the actuators/drives. Once the probe starts moving the image acquisition is done continuously using NI-IMAQ 1407. The acquired image is processed real time using an accurate object-tracking algorithm, which has low computational cost and gives better performance. Predictor-corrector filter (Kalman filter) is used for real-time filtering of the noise. All the experimental results are presented.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"2004 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127327972","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}
引用次数: 2
Speaker adaptation through speaker specific compensation 通过说话人特定补偿来适应说话人
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458361
S. Laxman, P. Sastry
{"title":"Speaker adaptation through speaker specific compensation","authors":"S. Laxman, P. Sastry","doi":"10.1109/SPCOM.2004.1458361","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458361","url":null,"abstract":"This paper describes a new speaker adaptation strategy that we term speaker specific compensation. The basic idea is to transform speech of a speaker in a way that renders it recognizable by a speaker dependent classifier built for another speaker. The compensating filter is learnt as a cepstral vector using labeled speech samples of the speaker. Using some ideas about combining multiple pattern classifiers, we present a new speaker independent speech recognition system that uses a few speaker dependent classifiers along with a bank of cepstral compensating vectors learnt for a large number of other speakers. Each of the speaker dependent classifiers is trained on the given speech samples of only one speaker and is never retrained or adapted thereafter. We present some results to illustrate the effectiveness of this speaker specific compensation idea.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121864269","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}
引用次数: 0
An agent based approach to QoS routing in mobile ad-hoc networks 移动自组织网络中基于代理的QoS路由方法
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458362
S. Manvi, V. Telsang
{"title":"An agent based approach to QoS routing in mobile ad-hoc networks","authors":"S. Manvi, V. Telsang","doi":"10.1109/SPCOM.2004.1458362","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458362","url":null,"abstract":"Multimedia applications require stringent QoS (quality of service) requirements such as guaranteed bandwidth, bounded end-to-end delays, bounded jitters, etc. Hence there is a necessity to find QoS aware paths for data transfer to satisfy the application requirements. This is very complex to achieve in MANETs (mobile ad-hoc networks) due to its inherent characteristics such as dynamic topology, node mobility, scarce resources, etc. In this paper we propose a scheme to perform on-demand QoS routing in MANETs by using agents. The scheme uses two types of agents: static agents and mobile agents. The static agents collect the resource information of the neighboring nodes. The mobile agents roam in the network hosted by a source to find the QoS path (bandwidth and delay constrained) by interacting with static agents. The scheme is simulated in various network scenarios to test its operation effectiveness. The proposed method offers adaptability, flexibility and supports component based software engineering concepts such as maintainability, customization, software reuse, etc.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122778455","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}
引用次数: 4
Estimation of LOS rates and angles using EKF from noisy seeker measurements 利用噪声导引头测量的EKF估计LOS速率和角度
2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04. Pub Date : 2004-12-11 DOI: 10.1109/SPCOM.2004.1458515
M. Ananthasayanam, A. Sarkar, Prashant Vohra, A. Bhattacharya, R. Srivastava
{"title":"Estimation of LOS rates and angles using EKF from noisy seeker measurements","authors":"M. Ananthasayanam, A. Sarkar, Prashant Vohra, A. Bhattacharya, R. Srivastava","doi":"10.1109/SPCOM.2004.1458515","DOIUrl":"https://doi.org/10.1109/SPCOM.2004.1458515","url":null,"abstract":"This paper deals with estimation of line of sight rates and angles of evader with respect to pursuer from available noisy active seeker measurements. During terminal guidance, on board seeker of pursuer acquires the required measurements, which are very noisy, non-Gaussian and correlated due to glint, eclipsing and thermal noise. Also there is an aperiodic data loss in the inner gimbal pitch and yaw rate measurement channels due to eclipsing. An extended Kalman filter has been used to estimate the line of sight rates and angles along with observer states from seeker measurements under such practical situations. The estimation algorithm has been validated under simulated environment and the results are encouraging. Future research to be carried out is also discussed at the end.","PeriodicalId":424981,"journal":{"name":"2004 International Conference on Signal Processing and Communications, 2004. SPCOM '04.","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132299951","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}
引用次数: 11
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