中国开放科研知识云: 检索

Retrieval of snow depth in Northeast China using FY-3B/MWRI passive microwave remote sensing data (EI CONFERENCE) 会议论文
Satellite Data Compression, Communications, and Processing VIII, August 12, 2012 - August 13, 2012, San Diego, CA, United states
Ren R.; Gu L.; Chen H.; Cao J.

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Comparing with optical remote sensing techniques passive remote sensing data have been proved to be effective for observing snowpack parameters such as snow depth and snow water equivalent which can penetrate snowpack without clouds interferences. The Microwave Radiation Imager (MWRI) loaded on the Chinese FengYun-3B (FY-3B) satellite is gradually used in the global environment research through November 2011. In this paper we proposed a snow depth retrieval algorithm to estimate snow depth in Northeast China using MWRI passive microwave remote sensing data. A decision tree method of snow identification was firstly designed to distinguish different snow cover conditions in order to eliminate other interference signals. After using the proposed decision tree method the processing results were further used to retrieve the snow depth in Northeast China. Finally the practical snow depth data and the MODIS data were collected for the accuracy assessment of the proposed snow depth retrieval method. The experimental results demonstrated that the RMSE of snow depth used the proposed method was approximately 3 cm in Northeast China. 2012 SPIE.

Tracking error estimate for theodolite based on general regression neural network (EI CONFERENCE) 会议论文
3rd international Conference on Manufacturing Science and Engineering, ICMSE 2012, March 27, 2012 - March 29, 2012, Xiamen, China
Li M.; Gao H.

收藏 | 浏览/下载：12/0 | 提交时间：2013/03/25

To efficiently evaluate the tracking index of theodolite as well as avoiding influence resulted from higher harmonics when used opto dynamic target and use equivalent sine to evaluate the tracking index in this paper we resorted to General Regression Neural Network to do the new research on theodolite tracking accuracy evaluation method. Experimental results indicate that the method realized the equivalent sine to evaluate the tracking index of theodolite and avoided the higher harmonics influence with opto dynamic target. The research in this paper has important value to the engineering practice. (2012) Trans Tech Publications.

Evaluation of spatial upscaling methods based on remote sensing data with multiple spatial resolutions (EI CONFERENCE) 会议论文
Satellite Data Compression, Communications, and Processing VIII, August 12, 2012 - August 13, 2012, San Diego, CA, United states
Ren R.; Gu L.; Cao J.; Chen H.; Sun J.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

In most applications of remote sensing data special spatial information is required from a finer to a coarser spatial resolution with appropriate upscaling methods. The purpose of this paper is to compare and evaluate current spatial upscaling methods using MODIS remote sensing data with multiple spatial resolutions. In the research Northeast China was selected as the study area. MODIS data with spatial resolutions of 250 m (2 bands) and 500 m (7 bands) were used as the test data. Through using the selected upscaling methods the Band 1 and Band 2 data of MODIS were scaled up from 250 m to 500 m spatial resolution. On the basis of land cover characteristics of Northeast China the MODIS data located in the study area was classified into the five land cover types including water grasslands forests farmlands and bare lands using maximum likelihood method. The land cover classification results were further compared with MODIS Land Cover Type product. Finally Structural Similarity (SSIM) was selected to evaluate the effects of these upscaling methods. The research can provide more useful information for spatial scaling transformation in remote sensing data applications. 2012 SPIE.

The effect of backlash nonlinear on resonance frequency of electric actuator transmission system (EI CONFERENCE) 会议论文
3rd IEEE International Conference on Advanced Computer Control, ICACC 2011, January 18, 2011 - January 20, 2011, Harbin, China
Han X.; Ge M.; Bai Y.; Jia H.; Ge W.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

In order to study the effect of backlash nonlinear on resonance frequency of electric actuator transmission system then Finally in the premise of meeting the stability the dynamic equilibrium equation of transmission system with backlash is established it makes dynamic simulation analysis for the transmission system based on virtual prototype technology it establishes balanced equation of dynamics system with backlash the effect of backlash on system natural frequency and resonance frequency and the theoretical values and simulation values are compared. Theoretical analysis and simulation results show that the theoretical analysis is basically consistent with simulation results when it is zero backlash and does some theory research and dynamic analysis of backlash nonlinearity and system natural frequency and resonance frequency. First and the error of theoretical analysis and simulation results is within 10%. Therefore according to describing function to theoretically model the backlash nonlinear it can be concluded that considering the transmission system theoretical analysis of backlash nonlinearity is feasible the relation between describing function and the amount of backlash and input amplitude is analyzed and it is much closer to the actual system with instructive significance. 2011 IEEE.

Study on spectrograph for ionosphere: A broadband imaging instrument prototype for far-ultraviolet (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Yu L.; Wang S.-R.; Lin G.-Y.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

Current research on space-based exploration for the ionosphere needs more advanced technologies. Because the spectral signals in the ionosphere distributing basically in the far-ultraviolet waveband are very weak. Usual spectrometer structures and detectors such as CCD can't receive enough information. Based on this principle of atmospheric sounding the imaging spectrometer prototype for ionosphere detection application was designed to solve the problem. This prototype consists of the telescope and the imaging spectrometer. The simple structure and small number of mirrors can help higher transmission efficiency be achieved and weak signals detection be implemented. The telescope is an off-axis parabolic mirror and the spectrometer is a modified Czerny-Turner spectral imaging system. Modified Czerny-Turner spectrometer contains a spherical mirror a fixed plane grating and a toroidal mirror. By adjusting the incident angle to the collimating mirror and using toroidal mirror coma and astigmatism were corrected well. We also optimize distances between the grating to the focusing mirror and the focusing mirror to the image plane to improve disadvantages of traditional Czerny-Turner structure. Designed results demonstrate that aberrations are substantially corrected and high image quality can be obtained in broad waveband. The photon counting Wedge-Strip-Anode detector with micro-channel planes as the receiving plane is accepted for the instrument prototype. The other photon counting 2-D detector responding well for weak light such as Cross-Delay line detector and MAMA detector can also be used for detection. The calibration and performances testing system is made of a vacuum system a deuterium lamp a monochrometer and the instrument prototype. Results obtained from the experiment show that the spectral resolution is 2.4 nm and the spatial resolution is 80 m. The other calibration experiments are running. The technology of the spectrometer prototype is important for the research and applications of ionosphere remote sensing. 2011 SPIE.

Multi-focus image fusion algorithm based on adaptive PCNN and wavelet transform (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Wu Z.-G.; Wang M.-J.; Han G.-L.

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Being an efficient method of information fusion image fusion has been used in many fields such as machine vision medical diagnosis military applications and remote sensing.In this paper Pulse Coupled Neural Network (PCNN) is introduced in this research field for its interesting properties in image processing including segmentation target recognition et al. and a novel algorithm based on PCNN and Wavelet Transform for Multi-focus image fusion is proposed. First the two original images are decomposed by wavelet transform. Then based on the PCNN a fusion rule in the Wavelet domain is given. This algorithm uses the wavelet coefficient in each frequency domain as the linking strength so that its value can be chosen adaptively. Wavelet coefficients map to the range of image gray-scale. The output threshold function attenuates to minimum gray over time. Then all pixels of image get the ignition. So the output of PCNN in each iteration time is ignition wavelet coefficients of threshold strength in different time. At this moment the sequences of ignition of wavelet coefficients represent ignition timing of each neuron. The ignition timing of PCNN in each neuron is mapped to corresponding image gray-scale range which is a picture of ignition timing mapping. Then it can judge the targets in the neuron are obvious features or not obvious. The fusion coefficients are decided by the compare-selection operator with the firing time gradient maps and the fusion image is reconstructed by wavelet inverse transform. Furthermore by this algorithm the threshold adjusting constant is estimated by appointed iteration number. Furthermore In order to sufficient reflect order of the firing time the threshold adjusting constant is estimated by appointed iteration number. So after the iteration achieved each of the wavelet coefficient is activated. In order to verify the effectiveness of proposed rules the experiments upon Multi-focus image are done. Moreover comparative results of evaluating fusion quality are listed. The experimental results show that the method can effectively enhance the edge details and improve the spatial resolution of the image. 2011 SPIE.

Random vibration analysis on the support of strapdown inertial navigation system (EI CONFERENCE) 会议论文
2nd Annual Conference on Electrical and Control Engineering, ICECE 2011, September 16, 2011 - September 18, 2011, Yichang, China
Hao X.; Li M.; Jia H.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

Vibration of the support is an important factor to the accuracy of strapdown inertial navigation. To get vibration characteristics of the support FEM model of the support was created with Ansys and then response characteristics were analyzed on the support under the separated random loads during carrier flight including the phases of subsonic and subsonic. To validate the analysis method wide band random vibration test was done on the points of the support which are used for mounting inertial instruments. The comparison of the analysis and the test data shows that the relative error of analysis result is not more than 13%. According to the two results the support structure was improved. Finally random vibration analysis was carried out on the improved one. The result shows that the acceleration response was largely reduced than before. This research can be a reference of performance improvement of the strapdown inertial support and navigation system precision. 2011 IEEE.

The new approach for infrared target tracking based on the particle filter algorithm (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
Sun H.; Han H.-X.

收藏 | 浏览/下载：50/0 | 提交时间：2013/03/25

Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring precision and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure but in order to capture the change of the state space it need a certain amount of particles to ensure samples is enough and this number will increase in accompany with dimension and increase exponentially this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining" we expand the classic Mean Shift tracking framework.Based on the previous perspective we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm can compensate shortcoming of the particle filter has too much computation and can effectively overcome the fault that mean shift is easy to fall into local extreme value instead of global maximum value.Last because of the gray and fusion target motion information this approach also inhibit interference from the background ultimately improve the stability and the real-time of the target track. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

The lightweight design of the inner framework of the opto-electronic stabilization platform based on finite element analysis (EI CONFERENCE) 会议论文
2011 IEEE 18th International Conference on Industrial Engineering and Engineering Management, IE and EM 2011, September 3, 2011 - September 5, 2011, Changchun, China
Zou Q.; Ma H.-L.; Hu Y.; Ding J.-W.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

The airborne opto-electronic stabilization platform should have the characteristics of high requirements for stability tracking accuracy and lightweight. In order to verify the rationality of the main load-bearing structure the inner-gimbal finite element analysis was performed. Because of the poor working conditions of the airborne opto-electronic stabilization platform and the wide range of working temperature variation -45 C 60 C according to the actual working environment air-resistance and temperature were added to the loads of the inner-gimbal in analysis. What's more based on the analysis results lightweight design was performed to the initial model and 64.37% of mass was decreased. The remarkable effect was obtained. This research is going to be instructive to design and production of the airborne opto-electronic stabilization platform in the future. 2011 IEEE.

Research on servo controller for high speed tracking system (EI CONFERENCE) 会议论文
2011 International Conference on Mechatronic Systems and Automation Systems, MSAS 2011, July 23, 2011 - July 24, 2011, Xi'an, China
Li M.; Gao H.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

To meet requirement of swiftness and minimization for the tracking system as well as realize horizontal high accuracy tracking measurement the automatic servo tracking measurement system has been designed. The two closed loop control bisection method and compound control have been applied into the system. Experimental results show that the maximum tracking error can be limited to less than 0.5and the regulator time can be 0.04s. The control project resonance frequency should be more than 200Hz and the sample frequency should be more than 400Hz to meet the control accuracy requirement. And these specific mechanical properties indexes are useful to mechanical working to make sure the design can be realization. So the research in this paper has important value to the engineering practice. (2011) Trans Tech Publications.

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