中国科学院机构知识库网格系统: 检索

Experimental Study of Overtopping on Sea Dikes and Coastal Flooding Under the Coupled Processes of Tides and Waves CNKI期刊论文 OAI收割
2022
作者: LI Yan-ting; ZENG Cheng-jie; Zhao Yi-han; HU Po; SUN Tian-ting

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storm surge water level variation wave overtopping coastal flooding experimental technique

Transitional compensation algorithm for correcting non-uniformity of LED display image (EI CONFERENCE) 会议论文 OAI收割
2012 2nd International Conference on Materials Science and Information Technology, MSIT 2012, August 24, 2012 - August 26, 2012, Xi'an, Shaan, China
Su W.-x.; Chen Y.-s.

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In order to solve the problem of high non-uniformity of LED display images which is caused by the edges of LED display panel during module splicing transitional compensation algorithm is proposed by improving the existed correction technique named the correction technique based on CCD. First introduce the three development stages of the LED display panel. Then the realization progress of the transitional compensation algorithm is described in detail after elaborating the principle of transitional compensation. Finally the algorithm is emplaned in a LED video control system to control the LED display panel whose display area is 1280960 and which is spliced by 3020 LED modules whose size are 6432. Experimental results show that this algorithm is able to reduce non-uniformity of LED display images from 29.3% before correcting to 0.95%. (2012) Trans Tech Publications Switzerland.

Improved method of target detection on optoelectronic hybrid joint transform correlator in cluttered scences (EI CONFERENCE) 会议论文 OAI收割
2011 3rd International Conference on Mechanical and Electronics Engineering, ICMEE 2011, September 23, 2011 - September 25, 2011, Hefei, China
作者: Yang L.; Yang L.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

A classical joint transform correlator (JTC) usually yields large correlation sidelobes as well as a large correlation peak width strong zero-order peak and low diffraction efficiency which make the detection ability of JTC lower. To overcome these difficulties firstly a joint power spectrum (JPS) subtraction technique in Fourier plane was proposed where reference image power spectrum and object image power spectrum are subtracted from the JPS before inverse Fourier-transform operation it is obvious that the modified JPS removes the zero-order term. Secondly a fringe-adjusted filter (FAF) was presented to suppress sidelobes and noises. The modified JPS is multiplied by a FAF before the inverse Fourier-transform operation to obtain the cross-correlation peak. Computer simulations demonstrated the improved method can obviously remove zero-order diffraction and effectively suppress the sidelobes and noises compared with classic JTC and then improve the detection ability for JTC. Experimental results presented the sharp correlation peak and also confirmed the method effectiveness. (2012) Trans Tech Publications Switzerland.

Modeling and variable structure control of a vehicle flexible manipulator (EI CONFERENCE) 会议论文 OAI收割
10th World Congress on Intelligent Control and Automation, WCICA 2012, July 6, 2012 - July 8, 2012, Beijing, China
作者: Wang Z.; Li Y.; Li Y.; Li Y.; Li Y.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

In this paper the mathematical modeling and the application of a new trajectory tracking control technique for hydraulic-driven rigid-flexible manipulator are concerned. To get a closer dynamic behavior of the real system both the flexible manipulator linkage and the actuator dynamics are considered. The exact dynamic model of flexible manipulator is derived using Lagrange principle and assumed modes method. The partial decoupled dynamic equation is derived using nonlinear decoupling feedback control method. The whole dynamic model is established by a driven Jacobin matrix which represents the coupling between hydraulic servo system and mechanical system. A variable structure controller with inverse dynamics is designed for trajectory tracking. To weaken the chattering of control signal saturation function is used to instead of sign function. The experimental results investigate the effectiveness of the proposed approaches. 2012 IEEE.

The research of the accurate measure of static transfer function for the TDI CCD camera (EI CONFERENCE) 会议论文 OAI收割
3rd International Photonics and OptoElectronics Meetings, POEM 2010, November 2, 2010 - November 5, 2010, Wuhan, China
Guo-Ning L.; Long-Xu J.; Jian-Yue R.; Wen-Hua W.; Shuang-Li H.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

In the test course of static transfer function of TDI CCD camera because of the influence that gets environmental and artificial etc. factor the value of static transfer function measured at any time is between unceasing fluctuation so make accuracy reduce. To solve this problem a kind of accurate measurement technique of static transfer function is put forward. First before carrying out the measure of static quiet of transfer function the best test point of transfer function of the TDI CCD camera must be determined it is parallel to guarantee the rectangle target surface of parallel optical pipe and camera focal plane maintenance parallel and again guarantee target strip in rectangle target and TDI CCD in camera focal plane maintenance vertical. TDI CCD catches rectangle target image per 1000 lines of target mark image as a measures sample of static transfer function exclude because of atmosphere tremble twisted vague rectangle target mark image retain 500 distinct and steady target mark image as measure sample set. Then calculate the static transfer function of each measure sample respectively take the average of all static quiet transfer function in measure sample set as the static transfer function of camera. Finally the measure of the static transfer function for TDI CCD camera makes error analysis. Experimental results indicate that the value of the static transfer function of TDI CCD camera measured with this kind of method is 0.2923 with before measurement technique comparison the value of static transfer function has raised 0.02 makes the accuracy of the measure of static transfer function have gotten raising.

Study on medical X-ray coherent scatter imaging and processing based digital flat detector (EI CONFERENCE) 会议论文 OAI收割
3rd International Conference on BioMedical Engineering and Informatics, BMEI 2010, October 16, 2010 - October 18, 2010, Yantai, China
作者: Li B.; Zhao J.; Li B.; Li B.; Liu J.

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It is introduced a novel imaging technique for medical diagnostic X-ray coherent scatter in this paper. A set of experimental equipment for X-ray coherent scatter imaging was set up with X-ray digital flat detector and medical diagnostic X-ray source. According to this equipment the scatter images obtained are made of some circles with the same center. It is vital to calculate the energy template to classify the different samples. It is difficult to separate them using the traditional threshold method due to noise and overlapped shadow. In this paper the image was transformed a binary image by using K-Means algorithm and Mathematical Morphology Methods. The effective region was extracted from the binary image inside the orthogonal energy projection space then to calculate the centroid of rings. Consequently the curve of the energy distribution was built. The experiment results show that our method is reasonable and feasible. The technique will have wide foreground of application .Besides the imaging of human bone content it can be used for various imaging of tissue and organs in biology. 2010 IEEE.

Linearity measurement for image-intensified CCD (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Zhang L.; Zhao Y.; Zhao Y.; Zhao Y.; Yan F.

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To the characteristic of the ultraviolet CCD (UV ICCD) technique of the linearity measurement of the UV ICCD camera is studied based on the theory of radiometry. Approach of linearity measurement is discussed and a kind of measurement system of the UV ICCD has been developed based on the method of neutral density filter. It is very important that the transmittance of the filter is independent of the wavelength in the method of neutral density filter. Black metal screen mesh with different transmittance is used in our system and calibration of the filters' transmittance in different working positions has been done. Meanwhile to assure the uniform of the received radiation on the target of the detector at any test points an integrating sphere is placed behind the neutral filter to balance light. The whole measurement system mainly consists of a deuterium lamp with high stabilization the attenuation film with transmission integrating sphere optical guide and electro-shift platform. Auto control is realized via special software during the test. With this instrument the linearity of the UV ICCD was measured. Experimental results show that the nonlinearity of the UV ICCD under fixed-gain is less than 2% and the uncertainty of measurement system is less than 4%. 2010 Copyright SPIE - The International Society for Optical Engineering.

Modulation transfer function measurement technique for image sensor arrays (EI CONFERENCE) 会议论文 OAI收割
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
作者: Jiang H.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

A new technique is demonstrated for measurement of modulation transfer function (MTF) on image sensor arrays. Fourier analysis of a low frequency bar target pattern is used to extract MTF at odd harmonics of a target pattern frequency up to and beyond Nyquist. The technique is particularly useful for linear image arrays (either conventional linescan or time-delay-integration devices) where conventional slanted-edge technique is not always applicable. The technique is well suited to simple implementation and can provide live presentation of the MTF curve which helps to ensure optimal alignment conditions are achieved. Detailed analysis of the technique and demonstration of experimental results are presented. 2010 SPIE.

New phase measurement method for laser rangefinder (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Meng Z.; Meng Z.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

A new phase measurement method is designed and presented by using the technique of signal shifting phase and the technique of signal multiplication for laser rangefinder. The intensity of laser light is modulated by cosine circuit signal at the same time the cosine circuit signal is thansformed sine signal by the shifting phase technique. Two signals mentioned above are multiplied by received signal from the target respectively then being transmitted into signal processor after passing through low band filter respectively. The result of phase-shift between the received signal and sent signal is calculated by means of signal processor and time-counter with double frequency of modulation signal. The proposed system is composed of four units such as control and count unit emitting and receiving unit of laser light signal processing unit and result display unit. The two most advantages of proposed system over others are its ability of proper isolation which reduces crosstalk and its independency thermal drift. Theoretical calculations and experimental results have shown the accuracy better than 2 mm. 2010 Copyright SPIE - The International Society for Optical Engineering.

Phase error estimation with broadband white light by Phase Diversity (EI CONFERENCE) 会议论文 OAI收割
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
作者: Wang Z.; Wang B.; Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

The technique of Phase Diversity (PD) is widely adopted to measure the wavefront error caused by atmosphere turbulence and system error. PD solves the Zernike coefficients of the wavefront by utilizing two images obtained with different defocus value. In this paper we propose a method to restore the image and estimate the wavefront error of an imaging system. And we use present white noises to verify the robustness of the algorithm. We design an experiment system and implement it in our laboratory. The proposed algorithm is validated by computer simulations and experimental results. To use a broadband white object in experimental system a reasonable simplification for the system model is done. Our results show that the robustness against Gaussian white noises of the method is better then the case when the variance value is 0.03. The proposed method can be used as a wavefront sensor and restore the degradative images by photoelectric image system. 2010 SPIE.