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Record 61 of
Title:A new DFT based channel estimation method for OFDM systems over multipath channels
Author(s):Wang, Jing(1); Qiu, Yuehong(1)
Source: Proceedings of the 2012 National Conference on Information Technology and Computer Science, CITCS 2012 Volume: Issue: DOI: 10.2991/citcs.2012.263 Published: 2012
Abstract:Channel estimation is one of the most significant technologies in the orthogonal frequency division multiplexing (OFDM) system and its accuracy will influence the performance of the whole system directly. Among all kinds of channel estimation algorithms, the least square(LS)estimation and the linear minimum mean-squared error (LMMSE) estimation are the most classic ones. However, both the two estimator are not able to reach a compromise between accuracy and computational complexity. The discrete Fourier transform (DFT) -based channel estimation can get a better performance by a time domain processing. In this paper, we proposed an improved DFT based channel estimation which suppresses the noise by a new threshold setting method. The computer simulation results demonstrate that the proposed algorithm can reach accuracy close to the LMMSE algorithm and its computational complexity is much lower than the LMMSE estimator. ? 2012. The authors - Published by Atlantis Press.
Accession Number: 20132216378704
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Record 62 of
Title:Automatic white balance of digital camera based on global probability distribution
Author(s):Guo, Huinan(1); Cao, Jianzhong(1)
Source: Advanced Materials Research Volume: 433-440 Issue: DOI: 10.4028/www.scientific.net/AMR.433-440.5443 Published: 2012
Abstract:The white balance is an important parameter of digital camera which makes a great impact on the application of digital cameras. However, due to the limitations of hardware of digital camera, the output image of digital camera cannot restore true colors of the objects under the different light sources conditions. And existing automatic white balance (AWB) algorithms have many application restrictions, particularly the single color image, the algorithms always failure to adjust. To solve this problem, this paper proposes an optimized algorithm based on the gray world assumption and HSI color model. According to the R, G and B color components probability distribution, the algorithm adjusts the image by using the difference value of color. Experimental results show that our algorithm can adjust images in complex situations; meanwhile these confirm that this method is not only effective, but also has the advantage of easy realization. ? (2012) Trans Tech Publications, Switzerland.
Accession Number: 20120414713041
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Record 63 of
Title:Optical system design of full-disc magnetic field telescope
Author(s):Zhao, Yiyi(1,2); Yang, Jianfeng(1); Ma, Xiaolong(1); Yan, Xingtao(1,2)
Source: Proceedings - 2012 5th International Symposium on Computational Intelligence and Design, ISCID 2012 Volume: 2 Issue: DOI: 10.1109/ISCID.2012.224 Published: 2012
Abstract:Full-Disc magnetic field telescope is an important instrument for astronomical observations.In order to meet the optical performance of the full-Disc magnetic field Telescope and the harsh coupling conditions of its filters, determined the optical parameters of the optical system by calculation. According to the calculation of the optical parameters, we puts forward a feasible optical structure which can make the system more compact under the premise of meeting the telescope In optical properties and filters coupling conditions. For the system, we have adopted the basic Idea of modular design, and the overall system is divided Into several subsystems were designed. The results show that the maximum wave front distortion(pv) of the system of all field of view Is 0.1327; the value of MTF at the spatial frequency of 67 Ip/mm is higher than 0.45 in every field. The Image quality of the system approximates to the dlffractive limit. ? 2012 IEEE.
Accession Number: 20130716008349
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Record 64 of
Title:Research on the first class m subsequence
Author(s):Duan, Yingni(1); Zhang, Haifeng(2); Lv, Hong(3); Fang, Junchu(3)
Source: Proceedings of the 2012 8th International Conference on Computational Intelligence and Security, CIS 2012 Volume: Issue: DOI: 10.1109/CIS.2012.119 Published: 2012
Abstract:For the difficulty of pseudo-random sequence generation, on the basis of construction research of the first class m subsequence, this paper realizes m subsequence based on shift register theory and deduces feedback function expression of m subsequence and analyses linear complexity of sequence by applying B-M algorithm. The analysis shows that linear complexity of m subsequence is larger than linear complexity of m sequence, close to a half of m sequence period. ? 2012 IEEE.
Accession Number: 20130716023328
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Record 65 of
Title:An auto-focus algorithm based on maximum gradient and threshold
Author(s):Mo, Chunhong(1); Liu, Bo(1)
Source: 2012 5th International Congress on Image and Signal Processing, CISP 2012 Volume: Issue: DOI: 10.1109/CISP.2012.6469961 Published: 2012
Abstract:In order to overcome the disadvantages of the traditional auto-focus algorithms which are poor in real-time performance, weak in anti-noise capability and vulnerable to the influence of contrast and background pixels, this paper proposes an auto-focus algorithm based on maximum gradient and threshold. It introduces a threshold factor and takes a new kind of adaptive threshold to remove the pixels contaminated by noise and background in the image, then uses improved Sobel operators to extract maximum gray gradient after image preprocessing and calculates evaluation value. The experimental results show that the proposed algorithm has good real-time performance, strong unimodality, high sensitivity and strong anti-noise capability. In addition, the algorithm is less influenced by contrast and background pixels of the image. It can also control the sensitivity and focusing range of the focusing function. So the proposed algorithm is most suitable for auto-focus subsystem of video monitoring and tracking system. ? 2012 IEEE.
Accession Number: 20131216134022
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Record 66 of
Title:A study on identification and suppressing algorithm of FOG's random noise
Author(s):Yuan, Hui(1); Liu, Zhaohui(2); Liang, Dongsheng(3); Cui, Kai(1)
Source: 2012 IEEE 5th International Conference on Advanced Computational Intelligence, ICACI 2012 Volume: Issue: DOI: 10.1109/ICACI.2012.6463365 Published: 2012
Abstract:In this paper, the Allan variance technique is used in analyzing the output signal of a fiber optic gyroscope, by which the characteristics of the noise terms in the angular velocity data was determined. Then we process the random drift data of the FOG with a Kalman Filter based on the theory of time series analysis. On the other hand, an LMS adaptive filter is also applied to the random drift data. Comparative analysis on the filtering effect and their advantages and disadvantages of both algorithms is carried out. The results show both algorithms has a certain role on suppressing the random drift of the gyroscope, and the LMS adaptive filter is more effective and has a better adaptability in practice. ? 2012 IEEE.
Accession Number: 20131116105481
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Record 67 of
Title:Research on image registration and mosaic based on vector similarity matching principle
Author(s):Qin, Jia(1,2); Yang, Jianfeng(1); Xue, Bin(1); Bu, Fan(1,2)
Source: Proceedings - 2012 5th International Symposium on Computational Intelligence and Design, ISCID 2012 Volume: 2 Issue: DOI: 10.1109/ISCID.2012.232 Published: 2012
Abstract:Scale invariant feature transform (SIFT) is a better corner extraction algorithm, but there are still mismatching problems in the feature matching step. A new matching principle based on vector similarity is proposed and then it is compared with traditional matching principle. Firstly, the matching feature points are detected by the new principle. Mismatching points are further removed by using the mutual mapping theory. Secondly, transformation matrix is calculated by random sample consensus (RANSAC). Furthermore, the matrix is optimized by Levenberg-Marquardt algorithm (L-M). Lastly, image mosaic is realized by image fusion. Experimental results indicate that compared with traditional matching principle, new matching principle has improved matching accuracy. It is able to apply new principle to image registration and image mosaic. ? 2012 IEEE.
Accession Number: 20130716008357
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Record 68 of
Title:A design of versatile image processing platform based on the dual multi-core DSP and FPGA
Author(s):Zhan, Zhen Huan(1,2); Hao, Wei(2); Tian, Yan(2); Yao, Da Wei(2); Wang, Xian Hong(2)
Source: Proceedings - 2012 5th International Symposium on Computational Intelligence and Design, ISCID 2012 Volume: 2 Issue: DOI: 10.1109/ISCID.2012.210 Published: 2012
Abstract:As an application of TI's latest multi-core DSP chip TMS320C6678 and Xilinx's FPGA chip XC5VLX110T, This paper designed and implemented a dual-DSP and FPGA real-time image processing system based on the Serial Rapid IO (SRIO), Hyperlink and reconfigurable technology. It used TMS320C6678 on-chip SRIO and Hyperlink interface module, XC5VLX110T on-chip Rocket IO modules, reconfigurable technology to implement a DSP and FPGA loosely coupled parallel interconnection reconfigurable system. On Embedded operating system's DSP / BIOS architecture, this paper implemented the program of hardware driver of bottom layer and the corresponding data transfer procedures, and also completed the transmission of digital images. ? 2012 IEEE.
Accession Number: 20130716008336
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Record 69 of
Title:The study on image compression methods
Author(s):Chen, Zhi(1,2); Qiu, Yuehong(1)
Source: Advances in Intelligent and Soft Computing Volume: 137 AISC Issue: DOI: 10.1007/978-3-642-27866-2_34 Published: 2012
Abstract:Because of the higher resolution, the data volume of remote sensing image is very large. To communicate and use them on network, efficient compression is very important. In this study, we present the main subjects in the theory of data compression and some image compression methods. ? 2012 Springer-Verlag GmbH.
Accession Number: 20121814986461
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Record 70 of
Title:High precision edge detecting algorithm and realization of linear CCD based on FPGA
Author(s):Gao, Lina(1); Hu, Xiaodong(2)
Source: Advances in Information Sciences and Service Sciences Volume: 4 Issue: 20 DOI: 10.4156/AISS.vol4.issue20.38 Published: November 2012
Abstract:In order to improve the precision and speed of the linear CCD edge detecting system, in this paper, we proposed a new digital system which was used to detect the sub-pixel edge of the picture based on FPGA. Firstly, the CCD signal had been filtered by average filter before it entered the edge detecting system; secondly, the pixel edge can be detected by the algorithm that was used to detect the edge of the picture automatically, because the grads of grey scale breaks at the edge of the picture; lastly, cubic polynomials algorithm was used to detect the sub-pixel edge of picture. The edge detecting algorithm based on FPGA was designed with VHDL and Quartus II software, and the precision of the edge detecting algorithm was simulated and testes by using of MATLAB. The simulation and test results proved that the edge detecting algorithm in this paper had the characteristic of high precision, speed, and integration.
Accession Number: 20124715702023
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Record 71 of
Title:A new automatic exposure algorithm for astronomical image and Its FPGA implementation
Author(s):Wang, Hao(1,2); Cao, Jianzhong(1); Zhou, Zuofeng(1); Yan, Su(1); yan, Aqi(1,2)
Source: Advanced Materials Research Volume: 546-547 Issue: DOI: 10.4028/www.scientific.net/AMR.546-547.691 Published: 2012
Abstract:Automatic exposure control is the process of controlling the exposure time of the digital imaging system to obtain the desired image which can fit the human vision during the imaging process. A new automatic exposure algorithm for astronomical image is proposed. The pixel value weight is determined by exploring the maximum range of the image histogram. Additionally, the structure of the implementation based on FPGA and experiment results for real data are given. The experiment results show that the proposed algorithm can effectively achieve the real-time automatic exposure control. ? (2012) Trans Tech Publications, Switzerland.
Accession Number: 20124815716299
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Record 72 of
Title:Research on motion blurred image restoration
Author(s):Li, Bing(1,2); Zhan, Zhenhuan(1,2)
Source: 2012 5th International Congress on Image and Signal Processing, CISP 2012 Volume: Issue: DOI: 10.1109/CISP.2012.6469900 Published: 2012
Abstract:Motion Blurred Image Restoration is an important part of the image processing. We begin with an analysis of the degradation model of motion-blurred images. In this paper, we introduce and compare several recovery algorithms. We select one of them for in-depth specific experiments. We have analyzed correctly the reason for motion blur simulation images, the relationship between the ringing effect and the selection of algorithm parameters for restoring images. Finally, we briefly analyze the reasons for poor quality in image restoration. ? 2012 IEEE.
Accession Number: 20131216133961
