中国科学院机构知识库网格系统: 检索

Trajectory tracking control of a quad-rotor UAV based on command filtered backstepping (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Intelligent Control and Information Processing, ICICIP 2012, July 15, 2012 - July 17, 2012, Dalian, China
Gong X.; Bai Y.; Peng C.; Zhao C.; Tian Y.

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A quad-rotor unmanned aerial vehicle is an under-actuated strong coupled nonlinear system with parameters uncertainty and unknown external aerodynamic disturbance. The trajectory tracking control system with a nested double-loops structure is designed in this paper according to the coupling characteristic between the attitude angles and translational position. A PD control algorithm is proposed in the translational outer-loop to export the desired attitude signals to the attitude inner-loop. An adaptive backstepping control algorithm is designed in the inner-loop with respect to the uncertain rotational inertia and un-modeled disturbance while in order to reduce the computational complexity the command filtered approach is introduced into the designing procedure. And finally the numerical simulation results are presented for the trajectory tracking stabilization of a Quad-rotor which demonstrates the excellent performance of the proposed control system and illustrate its robustness in face of disturbance and uncertain parameters. 2012 IEEE.

The research of digltal CR medicine image adapitive enhancement method (EI CONFERENCE) 会议论文 OAI收割
4th International Conference on Mechanical and Electrical Technology, ICMET 2012, July 24, 2012 - July 26, 2012, Kuala Lumpur, Malaysia
Ming-Hui Z.; Yao-Yu Z.

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Digital CR medicine radiation image is in doctor's favor and has became medicine imaging technology new hot spot because of its high gray contrast powerful computer disposal function little radiation dosage non-film diagnosis different area consultation. But degradation of digital X-ray medical image such as low contrast and blurring during radiographic imaging caused by complexity of body tissue and effects of X-ray scattering and electrical noise etc. can worsen the results of analysis and diagnosis. So it is usually needed that CR medicine image is enhanced to improve its vision quality and easy to doctor's more accurate diagnosis. The general enhancement algorithms over enhancing the contrast and lose image details aiming at the defects an enhancement algorithm for CR image is proposed based on the ratio of deviation to mean of domain. The arithmetic enhance CR image edge details by adjusting factor K based on the ratio of deviation to mean of domain of CR image. Experiment results demonstrate that the algorithm enhances CR image detail and CR image enhanced has good visual effect the adaptive enhancement method is fit for CR medicine image. (2012) Trans Tech Publications Switzerland.

A hybrid median filter for enhancing dim small point targets and its fast implementation (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Multimedia and Signal Processing, CMSP 2011, May 14, 2011 - May 15, 2011, Guilin, Guangxi, China
Yang Q.

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Weak stars and middle altitude orbit satellites or high altitude orbit satellites are presented as dim point targets in images of astronomical observation. They have low intensity and occupy few pixels in image. In most situations the background of sky is always ununiform and there exists pulse noises. Thus results in targets submerging in background noises and low signal noise ratio (SNR). Median filter is an effective method for removing pulse noise. But it can blur image after modifying gray of non-noise pixels when image has low SNR. A hybrid median filter algorithm is proposed to process low SNR dim point targets image. The newly proposed method can suppress the pulse noises also can increase target $SNR$ and does not add extra fake targets. The time complexity of median filter is O(N2)(N is the widow size) and is difficult to implement in hardware. For quasi real time application a fast implementation of our hybrid median filter is proposed to reduce the time complexity to O(N). Experimental results show that the newly proposed algorithm is superior to ordinary median filter and fast median filter by comparing visual effect and performance. 2011 IEEE.

On optimal guidance arithmetic of Super-maneuverable aircraft (EI CONFERENCE) 会议论文 OAI收割
30th Chinese Control Conference, CCC 2011, July 22, 2011 - July 24, 2011, Yantai, China
作者: Liu Y.; Gong Y.; Wang Z.; Wang Z.; Liu Y.

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Due to the complexity of maneuverability Super-maneuver attack guidance of modern aircraft has become the most important function to be immediately solved and perfectly completed. Proceed from the maneuvering optimization position and based on the optimal control theory the optimal angle maneuver guidance arithmatic is proposed. On the basis of aircraft maneuver guidance algorithm we come up with a variety of constraint condition optimized index and optimization rule and present a set of steepest optimal angle maneuver guidance algorithm and the validity and feasibility of the steepest optimal angle maneuver guidance algorithm has been comfirmed by the super-maneuver guidance simulation. 2011 Chinese Assoc of Automati.

Optimization on motion estimation algorithm based on H. 264 (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
Wen X.; Li G.

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Motion estimation is a very important part of video compression. As a result of using precision of motion vector in H.264 encoder the computational cost increases rapidly and motion estimation is the most time-consuming stage. In this paper based on the UMHexagonS algorithm an optimized algorithm is proposed based on the dynamic search window selection big hexagon and small hexagon search mode respectively which saves motion estimation time effectively with a little quality loss. Experiments with some typical video sequences show that compared to the original UMHexagonS algorithm this new algorithm can save about 17.851 % motion estimation time and reduce the complexity of original scheme as well as enhance the real time performance of encoder and almost has no changes in the reconstructed picture quality and bitrates. 2010 IEEE.

Extracting sea-sky-line based on improved local complexity (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
作者: Zhang Y.-F.

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Sea-sky-line extraction under complicated sea-sky background is an important aspect of long-range target tracking research. An algorithm based on improved local complexity is proposed according to the feature that the sky and the sea usually show up at different gray levels in sea-sky background images. Median filter is applied first to remove peak noise and then the point set of sea-sky-line region which has the greatest change in image is obtained by calculating the local complexity of image and selecting a segmentation threshold. Finally Hough transform is used to extract the sea-sky-line. The experiment results indicate that this method can extract sea-sky-line under simple and complicated sea-sky backgrounds which is robust and can improve noise immunity of the algorithm. 2010 IEEE.

Adaptive segmentation algorithm for ship target under complex background (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
Wang A.-B.; Wang C.-X.; Su W.-X.; Dong Y.-F.

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Segmentation of ship target under complex background has important research significance in long-range ship tracking and identification and an adaptive segmentation algorithm is proposed according to background images with different complexity. Local complexity of image is first calculated in this algorithm and then the original image is preprocessed with different de noising methods according to local complexity finally the image is binarized based on local complexity and the target is segmented. The experiment results indicate that the algorithm is adaptive and can meet the requirements of real-time processing which lays a foundation for ship target detection under complex background. 2010 IEEE.

An adaptive image contrast enhancement based on differential evolution (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Congress on Image and Signal Processing, CISP 2010, October 16, 2010 - October 18, 2010, Yantai, China
Yang Q.

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Tubbs proposed a regularized incomplete beta function to represent some nonlinear transform functions most commonly used in image contrast enhancement. But how to define the coefficients of the beta function adaptively is still a problem. Applying the differential evolution in image contrast enhancement we utilize the global quickly search ability of the differential evolution algorithm adaptive mutation search at last searches the optimal values of beta function and gets an adaptive contrast enhanced image. To avoid trapping into local optimum a chaotic differential evolution algorithm is proposed. Experimental results show that the proposed algorithm can find the global optimal in few iterations and save largely computational time and complexity. 2010 IEEE.

A design of high-speed and low-consume parallel grouping RS code and simulation (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
Chen C.; Jin G.

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RS code is a linear error correction codes with better error correction capability is widely used in different kinds of occasions for communications or data storage. But for its high difficulty of coding and decoding algorithm and low throughput optimization RS algorithm is always studied as one of the focus in the error-correction field. A new coding method parallel coding and decoding data into groups in lower step finite field for avoiding complex matrix iteration and Chien search computation is proposed in this paper. It is proved that the coding and decoding throughput of the parallel grouping RS coder is increased and the hardware complexity is reduced with changeless error-correction capability from the simulation results using ModelSim SE 6.0 and synthetic results using ISE 9.11. 2010 IEEE.

Parameter identification of airborne vibrated image based on high-speed CCD (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Shi J.; Xue X.; Guo Y.

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In order to identify the vibration parameters of a vibrated image the principle and shortage of the traditional methods that based on image derivative and image transformation are analyzed and a new parameter identification method is proposed afterward. By placing a high-speed CCD aside the master CCD the vibration can be sampled accurately and more information can be obtained for parameter identification. The series frames that captured by high-speed CCD are processed by gray projection algorithm and the vibration extents between adjacent frames along x and y direction are obtained. By using simple triangle operations the vibration parameters can be identified and the computational complexity of which can be reduced greatly. The experiment shows that the parameter identification method based on high-speed CCD can identify the parameters of vibration with any form accurately. The precise of parameter identification for linear vibration is less than 2.95%. 2010 IEEE.