An improved algorithm of line detection is proposed to aim at the drawbacks of Hough transform. It reduces algorithm complexity based on the principle of 'many-to-one'. The idea 'from partial to global'...
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An improved algorithm of line detection is proposed to aim at the drawbacks of Hough transform. It reduces algorithm complexity based on the principle of 'many-to-one'. The idea 'from partial to global' is also adopted. The parameters of line are gotten in sub-areas in order to reduce quantization error. Then it searches other points of the line within whole image according to the parameters. algorithm complexity is also analyzed. Experiments show that the algorithm has better properties of computing efficiency and robustness.
In this paper, we present an iterative approach for the cancellation of phase errors induced by local oscillators in an OFDM receiver as well as the distortion resulting from nonlinear amplifiers. We investigate the i...
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In this paper, we present an iterative approach for the cancellation of phase errors induced by local oscillators in an OFDM receiver as well as the distortion resulting from nonlinear amplifiers. We investigate the influence of several parameters on the system performances, such as the modulation scheme, the number of carriers and the clipping ratio. Simulation results prove the effectiveness of the proposed algorithm for the cancellation of phase errors and non-linear distortion. We show that an error floor occurs for high values of the phase noise or the clipping ratio. This effect can be alleviated using an appropriate channel coding scheme, in conjunction with our iterative algorithm, for the correction of residual errors. We also show that the proposed algorithm complexity is nearly a linear function of the number of sub-carriers.
Euclidean Distance Transformation (EDT) converts one binary image into one distance image where each pixel has a value that equals to its Euclidean distance, which is calculated from its nearest foreg
Euclidean Distance Transformation (EDT) converts one binary image into one distance image where each pixel has a value that equals to its Euclidean distance, which is calculated from its nearest foreg
This paper considers the Alamouti's two-branch transmit diversity scheme. This scheme supports a maximum likelihood detection based on linear processing at the receiver. When no knowledge of the channel is availab...
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This paper considers the Alamouti's two-branch transmit diversity scheme. This scheme supports a maximum likelihood detection based on linear processing at the receiver. When no knowledge of the channel is available - at the transmitter and the receiver- the above scheme requires in general the estimation of the two discrete propagation channels seen from the two transmit antennas. Our objective is to evaluate the Alamouti's technique of diversity with a realistic estimation algorithm considering a very fast time-varying channel. For a robust channel estimation, we propose an Em-based maximum a posteriori semi-blind algorithm. This algorithm requires a convenient representation of the time-varying fading channel using a discrete version of the Karhunen-Loeve expansion theorem. The iterative receiver optimally uses pilot as well as unknown data symbols for improving channel estimation quality. The validity of the proposed algorithm is highlighted by simulation results. Moreover, a complexity evaluation of this algorithm and a comparison is provided for different scenarii.
Some applications use data formats (e.g. STL file format), where a set of triangles is used to represent the surface of a 3D object and it is necessary to reconstruct the triangular mesh with adjacency information. It...
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Some applications use data formats (e.g. STL file format), where a set of triangles is used to represent the surface of a 3D object and it is necessary to reconstruct the triangular mesh with adjacency information. It is a lengthy process for large data sets as the time complexity of this process is O(N log N), where N is number of triangles. Triangular mesh reconstruction is a general problem and relevant algorithms can be used in GIS and DTM systems as well as in CAD/ CAM systems. Many algorithms rely on space subdivision techniques while hash functions offer a more effective solution to the reconstruction problem. Hash data structures are widely used throughout the field of computer science. The hash table can be used to speed up the process of triangular mesh reconstruction but the speed strongly depends on hash function properties. Nevertheless the design or selection of the hash function for data sets with unknown properties is a serious problem. This paper describes a new hash function, presents the properties obtained for large data sets, and discusses validity of the reconstructed surface. Experimental results proved theoretical considerations and advantages of hash function use for mesh reconstruction. (C) 2003 Elsevier Science Ltd. All rights reserved.
This paper presents a performance analysis of a procedure for Quality of Service (QoS) negotiation in distributed multimedia applications. The numerical complexity of the procedure is regarded as a measure of its perf...
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ISBN:
(纸本)0780379632
This paper presents a performance analysis of a procedure for Quality of Service (QoS) negotiation in distributed multimedia applications. The numerical complexity of the procedure is regarded as a measure of its performance. The results are derived by combining formal analysis with computer simulation. It is shown that the performance of the considered procedure is better than of some known existing solutions.
We present in this paper the study of two classifications methods used in order to control in real-time some industrials parts. We present the practical frame in which is made the operations, natures of the anomaly to...
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ISBN:
(纸本)0780374029
We present in this paper the study of two classifications methods used in order to control in real-time some industrials parts. We present the practical frame in which is made the operations, natures of the anomaly to be detected as well as the features extractions method. We tested two techniques of classification, with different algorithm complexities and performances. We compare the results obtained on various features spaces. We end by a combinatorial perspective of results of classification.
A new algorithm for clipping a line segment against a pyramid in E-3 is presented. This algorithm avoids computation of intersection points that are not end points of the output line segment. It also solves all cases ...
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A new algorithm for clipping a line segment against a pyramid in E-3 is presented. This algorithm avoids computation of intersection points that are not end points of the output line segment. It also solves all cases more effectively. The performance of this algorithm is shown to be consistently better than that of existing algorithms, including the Cohen-Sutherland, Liang-Barsky, and Cyrus-Beck algorithms.
Based on analyzing disadvantages of the simple adaptive full search bit-plane matching motion estimation algorithm, some modifications such as computing method for the bit-planes, selection for the search origin and p...
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Based on analyzing disadvantages of the simple adaptive full search bit-plane matching motion estimation algorithm, some modifications such as computing method for the bit-planes, selection for the search origin and processing strategy for the inefficacy of the bit-plane matching criterion are proposed. Computer simulation results show that the improved algorithm is better than the old one. It can achieve similar performance to the full-search method and about 5/6 savings in computation for head and shoulder video sequences in videophones.
A comparative analysis was performed on the Monte Carlo collision estimator in the conjugated von-Neumann-Ulam scheme for solving systems of linear algebraic equations. It was found that there exist wide classes of li...
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A comparative analysis was performed on the Monte Carlo collision estimator in the conjugated von-Neumann-Ulam scheme for solving systems of linear algebraic equations. It was found that there exist wide classes of linear systems for which the Monte Carlo algorithm asymptotically (by dimension of system) has a better order of complexity than the iterative method. (C) 2000 Published by Elsevier Science B.V. All rights reserved.
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