2013
2013
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Record 49 of
Title:Mean shift based gradient vector flow for image segmentation
Author(s):Zhou, Huiyu(1); Li, Xuelong(2); Schaefer, Gerald(3); Celebi, M. Emre(4); Miller, Paul(1)Source: Computer Vision and Image Understanding Volume: 117 Issue: 9 DOI: 10.1016/j.cviu.2012.11.015 Published: 2013Abstract:In recent years, gradient vector flow (GVF) based algorithms have been successfully used to segment a variety of 2-D and 3-D imagery. However, due to the compromise of internal and external energy forces within the resulting partial differential equations, these methods may lead to biased segmentation results. In this paper, we propose MSGVF, a mean shift based GVF segmentation algorithm that can successfully locate the correct borders. MSGVF is developed so that when the contour reaches equilibrium, the various forces resulting from the different energy terms are balanced. In addition, the smoothness constraint of image pixels is kept so that over- or under-segmentation can be reduced. Experimental results on publicly accessible datasets of dermoscopic and optic disc images demonstrate that the proposed method effectively detects the borders of the objects of interest. ? 2013 Elsevier Inc. All rights reserved.Accession Number: 20134216859371 -
Record 50 of
Title:Calculation method of earth-atmosphere stray light illuminance on low-orbit space cameras
Author(s):Du, Yujun(1); He, Yinghong(2); Chen, Haibin(1); Xin, Weijuan(1); Xue, Bing(2)Source: Journal of Multimedia Volume: 8 Issue: 6 DOI: 10.4304/jmm.8.6.699-704 Published: 2013Abstract:The earth-atmosphere stray light can lower contrast ratio and SNR of spatial optical remote sensors, or even fail the system at certain conditions. Errors in the calculation of the stray light illuminance based on point source are very large, for the satellite's altitude is only several hundred kilometers and far less than the radius of the earth. This paper proposed a stray light illuminance calculating method which viewed the earth as a plane stray source and introduced the method in detail. Using the calculating method, earth-atmosphere stray light illuminance on the camera image plane for a low-orbit space camera at a typical position is calculated, and the results were compared with those calculated by viewing the earth as a point source, which evidently show that, when considering the earth-atmosphere stray light's effects on low-orbit space cameras, it's necessary to treat the earth as a plane extended light source. ? 2013 Academy Publisher.Accession Number: 20134817030991 -
Record 51 of
Title:Double image encryption scheme by using random phase encoding and pixel exchanging in the gyrator transform domains
Author(s):Liu, Zhengjun(1,2); Zhang, Yu(1); Li, She(3); Liu, Wei(3); Liu, Wanyu(1); Wang, Yanhua(4); Liu, Shutian(3)Source: Optics and Laser Technology Volume: 47 Issue: DOI: 10.1016/j.optlastec.2012.09.007 Published: April 2013Abstract:We present a double image encryption scheme by using random pixel exchanging and phase encoding in gyrator domains. Two original images are regarded as the amplitude and phase of a function in the encryption algorithm. The pixels of the two images are exchanged randomly by controlling of a matrix. The same random matrix is used in the process of pixel exchanging and phase encoding for saving space in the application of transmission and storage of key. Some numerical simulation results are made for demonstrating the performance and security of the double image encryption. ? 2012 Elsevier Ltd.Accession Number: 20124715686002 -
Record 52 of
Title:Coordination fault diagnosis based on RBF
Author(s):Xu, Rui Hua(1); Wang, Zheng Zhou(1); Yan, Ya Dong(1); Ma, Cai Wen(1)Source: Applied Mechanics and Materials Volume: 329 Issue: DOI: 10.4028/www.scientific.net/AMM.329.278 Published: 2013Abstract:In large-scale complex system, The establishment of a fast, accurate fault diagnosis system is more difficult because there exist many uncertain elements between the fault cause and the fault sign.A fault diagnosis system is established based on RBF cloud neural network,the RBR (rule-based reasoning) and the CBR (case-based reasoning).The fault diagnosis system not only has the advantages of self-learning, high accuracy, randomness, fuzziness, etc,and has the advantages of independently of mathematical model,rich knowledge representation, mighty problem solving ability, etc. Theoretical analysis and simulation results show that the system is feasible and effective for fast and accurate fault positioning of complex systems. ? (2013) Trans Tech Publications, Switzerland.Accession Number: 20132916520854 -
Record 53 of
Title:Implementation and performance of image filtering on GPU
Author(s):Chen, Xi(1); Qiu, Yuehong(1); Yi, Hongwei(1)Source: Proceedings of the 2013 International Conference on Intelligent Control and Information Processing, ICICIP 2013 Volume: Issue: DOI: 10.1109/ICICIP.2013.6568129 Published: 2013Abstract:Image filtering is one of the most important parts in the image-processing. It takes much more time to performance the convolution in image filtering on CPU since the computation demanding of image filtering is massive. Contrast to CPU, GPU may be a good way to accelerate the image filtering. CUDA(Compute Unified Device Architecture) is a parallel computing architecture developed by NVIDIA. CUDA is highly suited for general purpose programming on GPU which is a programming interface to use the parallel architecture for general purpose computing. This interface is a set of library functions which can be coded as an extension of C language. In this paper, the filtering was implemented in the frequency domain instead of the spatial domain since the filtering in the frequency domain is faster than convolution in the spatial domain if we have filters with many coefficients and filtering in 2D. Compared with the traditional method of image filtering which was performed on CPU, the implementation of image filtering on GPU has a speedup of approximately 10 times. GPU has great potential as high-performance co-processor. ? 2013 IEEE.Accession Number: 20133616702343 -
Record 54 of
Title:Mechanical passive compensation for athermalisation design of infrared optical system
Author(s):Zhang, Zhi(1); Zhang, Zhaohui(1); Fan, Zheyuan(1); Yan, Aqi(1); Zhang, Jian(1); Yang, Hongtao(1); Cao, Jianzhong(1)Source: Key Engineering Materials Volume: 552 Issue: DOI: 10.4028/www.scientific.net/KEM.552.93 Published: 2013Abstract:Optical equipments especially those for aerospace application are expected to work over a wide temperature range. The change of temperature could cause the refractive index change of infrared glass elements. Furthermore, it would lead to the defocus of the image surface and the performance degradation, so the method of temperature compensation must be adopted, which could make sure that optical system would adapt to the change of ambient temperature. A method of temperature compensation with mechanical passive compensation is briefly described, and an example is also given. The quality of image could be optimized through mechanical passive compensation, depending on the differences of metal and non-metallic thermal expansion coefficient. The results show that the optical system works stablely in the designed temperature range. It is of great importance to the athermalisation design of infrared optical system. ? (2013) Trans Tech Publications, Switzerland.Accession Number: 20133016543319 -
Record 55 of
Title:Optical color image hiding scheme based on chaotic mapping and Hartley transform
Author(s):Liu, Zhengjun(1,2,3,5); Zhang, Yu(1); Liu, Wei(4); Meng, Fanyi(3); Wu, Qun(3); Liu, Shutian(4)Source: Optics and Lasers in Engineering Volume: 51 Issue: 8 DOI: 10.1016/j.optlaseng.2013.02.015 Published: August 2013Abstract:We present a color image encryption algorithm by using chaotic mapping and Hartley transform. The three components of color image are scrambled by Baker mapping. The coordinates composed of the scrambled monochrome components are converted from Cartesian coordinates to spherical coordinates. The data of azimuth angle is normalized and regarded as the key. The data of radii and zenith angle are encoded under the help of optical Hartley transform with scrambled key. An electro-optical encryption structure is designed. The final encrypted image is constituted by two selected color components of output in real number domain. ? 2013 Elsevier Ltd. All rights reserved.Accession Number: 20131716234692 -
Record 56 of
Title:Design and simulation of attitude determination and control subsystem of cubesat using extended kalman filtering and linear quadratic gain controller
Author(s):Han, Xiao(1); Yang, Xiao Jun(1); Abbas, Naqvi Najam(2)Source: Advanced Materials Research Volume: 694 697 Issue: DOI: 10.4028/www.scientific.net/AMR.694-697.1582 Published: 2013Abstract:This paper describes an integral scheme of the design and simulation of the Attitude Determination and Control Subsystem (ADCS) of CubeSat. CubeSat is an educational low-cost, cube-shaped Pico spacecraft. Attitude Determination (AD) is the problem of expressing the orientation of a spacecraft with respect to a given coordinate system. Three axis magneto-resistive digital magnetometer is selected as an attitude sensor. The International Geomagnetic Reference Field (IGRF) is used as reference for magnetometer to obtain attitude information. An enhanced orbit estimate/propagator is implemented to provide position information to IGRF model. Satellite environmental torque is modeled along with satellite kinematics and dynamics. Attitude estimation is done using Extended Kalman Filter (EKF) while the magnetic coils are used as actuators. Attitude Control is applied using Linear Quadratic Regulation (LQR) Controller. The designed ADCS is implemented in Matlab/Simulink. ? (2013) Trans Tech Publications, Switzerland.Accession Number: 20132416421104 -
Record 57 of
Title:Research on modeling and simulation of expert_PID controlled servo system based on MATLAB/S-function
Author(s):Kang, Fei(1); Liang, Yan Bing(1)Source: Applied Mechanics and Materials Volume: 347-350 Issue: DOI: 10.4028/www.scientific.net/AMM.347-350.604 Published: 2013Abstract:The paper elaborates Expert_PID controller applied in servo system. Illustrates an Sfunction construction method on complex control law. Designs an Expert_PID controller based on MATLAB/S-function and writes partial core code of Expert_PID controller. Establishes the simulink model of servo system based on Expert_PID control law, gets the simulation result. Compared with the traditional discrete PID control law, the result demonstrates that Expert_PID controller can obtain excellent control qulity. ? 2013 Trans Tech Publications Ltd, Switzerland.Accession Number: 20133616698513 -
Record 58 of
Title:Design of camera and spectrometer dual-use system
Author(s):Qi, Yong-Hong(1,2); Xue, Bin(1); Zhao, Yi-Yi(1,2); Tao, Jin-You(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8910 Issue: DOI: 10.1117/12.2033622 Published: 2013Abstract:Imaging spectrometers based on prism-grating-prism (PGP) have advantage of direct vision, as a basis for the design of an optical system for a spectrometer and camera dual-use, the system can plug the light splitting element to switch between the spectrometer and camera. This paper has discussed the working principles and structure of the PGP and spectrometer, collimating and focusing lens design principles, then the design result has been presented. The spectral range of the system is 400-800nm, the pixel size of CCD used is 10um × 10um, 1010 × 1018 pixels, the object space numerical aperture is 0.1. In order to reduce the cost and eliminate aberration, collimating lens and focusing lens have symmetric structure, in order to improve the diffraction efficiency, PGP uses the volume phase holographic transmission grating. After optimization the design by ZEMAX software, the whole spectral range resolution is better than 1nm in average, the MTF at Nyquist frequency is greater than 0.7, the length of the whole system is 87mm. ? 2013 SPIE.Accession Number: 20141317516381 -
Record 59 of
Title:Study on NNPID-based adaptive control for electro-optical gyro stabilized platform
Author(s):Zhao, Bing(1,2); Cao, Jianzhong(1); Yang, Hongtao(1); Dong, Xiaokun(1,2); Wang, Jihong(1,2); Gong, Zhendong(1,2); Fan, Xinming(1,2)Source: Proceedings - 2013 International Conference on Mechatronic Sciences, Electric Engineering and Computer, MEC 2013 Volume: Issue: DOI: 10.1109/MEC.2013.6885096 Published: 2013Abstract:The working environment of airborne photo-electric stabilized platform is very atrocious and the platform is a time-varying system which has inherent nonlinearity. So we cannot obtain accurate mathematical model which makes it is difficult to obtain good control effects by traditional control method like conventional PID. Given the neural network's self-learning and self-adaptive characteristics which can adjust PID parameters automatically. This paper proposes a feed-forward neural network PID control method based on improved BP (Back Propagation) algorithm. The simulation results show that the improved algorithm can effectively solve the problems caused by classical PID control. Besides, the improved algorithm has very fast response speed, good real-time performance and less static-error. It can indeed meet the practical application requirements. ? 2013 IEEE.Accession Number: 20145100346511 -
Record 60 of
Title:Adaptive distance regularized level set method and its application to image segmentation
Author(s):Yu, Yali(1,2); Qu, Youshan(1); Han, Yameng(1); Tan, Jiahai(1)Source: Proceedings - 2013 5th International Conference on Intelligent Human-Machine Systems and Cybernetics, IHMSC 2013 Volume: 1 Issue: DOI: 10.1109/IHMSC.2013.99 Published: 2013Abstract:The distance regularized level set method has the advantage of maintaining the regularity of the level set function without re-initialization. However, it has the disadvantage of requiring the initial curve around or inside the detected objects. In this paper, an adaptive distance regularized level set method is designed. Firstly, the local energy term is introduced to make the method robust to how and where the initial curve is selected and can successfully segment the images with intensity heterogeneity. Secondly, a Gaussian filter is utilized to ensure the smoothness and regularity of the level set function and eliminate re-initialization. Furthermore, the narrow band method is applied in the adaptive distance regularized level set method to reduce the computation and the convergence time. The results of the comparative experiments show the advantages of the designed method. ? 2013 IEEE.Accession Number: 20140317205676