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浏览/检索结果: 共11条，第1-10条 帮助

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Progress of Ecological Restoration Research Based on Bibliometric Analysis 期刊论文  OAI收割
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH, 2023, 卷号: 20, 期号: 1
作者:  Wei, Xi;  Song, Wei;  Shao, Ya;  Cai, Xiangwen
  |  收藏  |  浏览/下载：33/0  |  提交时间：2023/02/03
Visual analysis of the evolution and focus in landslide research field 期刊论文  OAI收割
JOURNAL OF MOUNTAIN SCIENCE, 2019, 卷号: 16, 期号: 5, 页码: 991-1004
作者:  Yang, Jingi;  Cheng, Chang-xiu;  Song, Chang-qing;  Shen, Shi;  Ning, Li-xin
  |  收藏  |  浏览/下载：30/0  |  提交时间：2020/11/03
STEP Mission: Search for Terrestrial Exo-Planets 会议论文  OAI收割
European Planetary Science Congress 2013,, London, UK, 2013
Chen D.; Wu; J.; Li B.
收藏  |  浏览/下载：32/0  |  提交时间：2014/04/30
Design and fabrication of imaging optical systems with freeform surfaces (EI CONFERENCE) 会议论文  OAI收割
Current Developments in Lens Design and Optical Engineering XIII, August 13, 2012 - August 15, 2012, San Diego, CA, United states
作者:  Zhang F.;  Wang L.;  Wang L.;  Wang L.;  He X.
收藏  |  浏览/下载：33/0  |  提交时间：2013/03/25
Multi-focus image fusion algorithm based on adaptive PCNN and wavelet transform (EI CONFERENCE) 会议论文  OAI收割
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.
收藏  |  浏览/下载：78/0  |  提交时间：2013/03/25
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.  
Mapping the research on scientific collaboration 期刊论文  OAI收割
chinese journal of library and information science, 2010, 卷号: 3, 期号: 1, 页码: 1-19
HOU Jianhua; CHEN Chaomei; YAN Jianxin
收藏  |  浏览/下载：18/0  |  提交时间：2012/09/18
Energy-saving scheduling strategy for elevator group control system based on ant colony optimization (EI CONFERENCE) 会议论文  OAI收割
2010 IEEE Youth Conference on Information, Computing and Telecommunications, YC-ICT 2010, November 28, 2010 - November 30, 2010, Beijing, China
作者:  Zhang J.-L.;  Li J.-F.
收藏  |  浏览/下载：26/0  |  提交时间：2013/03/25
Elevator group control scheduling is to dispatch every elevator to serve call requests from different floors based on some certain goal. It's a kind of typical combinatorial optimization problems. Ant colony algorithm is good at solving the discrete combinatorial optimization  its well global optimization ability and quick convergence velocity are both necessary to a scheduling algorithm. Moreover  reducing passengers' waiting and traveling time is the main focus of current dispatching algorithms  neglecting the energy consumed by the elevator system. So it's necessary to research on energy-saving algorithms. For the purpose of elevator group's energy-conservation run  the objective function of energy is built  ant colony model for elevator group control system is created  its optimization mechanism is figured out  and convergence of the algorithm is studied in this paper. Simulation results show the effectiveness of the strategy. 2010 IEEE.  
Far-field focusing of laser beam based on digital image processing techniques (EI CONFERENCE) 会议论文  OAI收割
Optoelectronic Imaging and Multimedia Technology, October 18, 2010 - October 20, 2010, Beijing, China
作者:  Zhao S.;  Tian Y.-Z.;  Liu L.-S.;  Guo J.;  Zhang H.-Y.
收藏  |  浏览/下载：28/0  |  提交时间：2013/03/25
In order to lead the laser beam transmit in the atmosphere convergently  an experiment of laser focus at the distance of 450m and 300m has been operated in the outdoor place. The actual manipulations are as follows: Firstly  the laser was collimated by a beam expander  then the near-parallel laser beam was transmitted with a Galileo telescope system  and the distance between the concave lens and the convex lens can be tuned through a precise displacement platform  so the focus of the system changed due to the tiny displacement of the concave lens. Secondly  the average power of the laser spot can be measured using power meter  the power is 47.67mW and the standard deviation is 0.67mW while the focal length is 450m. Thirdly  the energy distribution was found through the laser beam analyzer. The spot images were saved using the beam analyzer  then the saved image can be processed with Matlab software afterwards. The function named EDGE and Sobel operator was used in the pre-processing of the saved image  then method of median filter was used in the course of image de-noising and 53H filter was adopted in the signal analysis. The diameter of laser spot was obtained by the method above  the diameter is 5.56mm and the standard deviation is 0.24mm. The spot center excursion is 0.56mm  it is 10.43% of the total diameter of the laser spot. At last  the key factors of the energy dissipation in the focusing system can be summarized as follows: restriction of the diffraction limit  attenuation in the atmosphere  geometrical aberration of optical system  and the diffraction limit and the geometrical aberration are significant in the three factors above  so we can reduce the impact of the both factors during the design of optical system. The reliable referenced data of the system design can be acquired through the primary experiment research. 2010 SPIE.  
The effect on tolerance distributing of an off-axis three mirror anastigmatic optical system with wavefront coding technology (EI CONFERENCE) 会议论文  OAI收割
Optical System Alignment and Tolerancing II, August 10, 2008 - August 11, 2008, San Diego, CA, United states
作者:  Yan F.;  Zhang X.-J.;  Yan F.
收藏  |  浏览/下载：35/0  |  提交时间：2013/03/25
The wavefront coding technology is known as a system-level technology which can extend the depth of focus of optical system by innovative optical design and image restoration. This technology can control misfocus related aberrations including misfocus  astigmatism  and Petzval curvature  temperature-related misfocus in digital imaging systems. It can also help optical system tolerate more residual error in optical manufacturing and alignment besides misfocus. The brief introduction of wavefront coding technology and the wavefront coded TMA system under research is presented respectively in part 1 and part 2. The "MTF similarity" is defined to describe the relationship among MTF at different position or different fields in the third part. It is also shown in this part that the MTF similarity of wavefront coded system is much higher than the normal system within a large range. In part 4 comparison between the origin system and the new system with wavefront coding technology is provided after multiple errors are introduced  from which it can be observed that the system with wavefront coding technology can tolerate much bigger error than origin system. The error tolerance is re-distributed according to a new criterion based on MTF similarity. If the MTF similarity is less than a certain value  it can be regarded that the system can tolerate the residual error. The new error tolerance is displayed and it is shown that the wavefront coding technology can also loosen the error distributing besides extended the depth of focus.  
Research on the support structure of the primary mirror of large-aperture telescope (EI CONFERENCE) 会议论文  OAI收割
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Large Mirrors and Telescopes, July 8, 2007 - July 12, 2007, Chengdu, China
Yang W.; Jingxu Z.
收藏  |  浏览/下载：28/0  |  提交时间：2013/03/25
Large-aperture telescope can be used in surveying battlefield  researching landform  searching object  real-time monitoring  imaging  detecting and identifying spatial targets and so on. A large-aperture telescope for achieving high resolution power is designed to monitor spatial target and image in real time. Real-time monitoring plays an important role in military conflicts. The orbit parameter of object  quantity  geometrical shape parameter and so on can be obtained by detect spatial target. With the development of optical technology  people require larger aperture in optics-electronic (OE) system. By increasing optical aperture  the ability of collecting light and resolution power in the system can be enhanced. But the support structure of the primary mirror of large-aperture telescope will be a very difficult problem. With the increase of primary mirror aperture  the weight of the primary mirror will become larger than before. The root mean square (rms) of the primary mirror is affected by many factors  such as deadweight  deformation of heat  environment and so on. Due to the primary mirror of telescope is an important component of telescope system. By reducing the weight of primary mirror  precision of the system is ensured. During the designing phase  one can consider the supporting project of the primary mirror synthetically and analyze it roundly according to technical requirement of optical system and the effect factors. The final structural design can be reasonable. In an astronomical telescope  the surface of reflector is an important part for collecting dark radiation of celestial bodies. Its surface shape will have an effect on collecting efficiency of telescope radiant energy directly. So the rms must be very high. Optical system of large aperture  small wavelength and small focus can receive maximal light intensity. For ground-based optical astronomical telescope  the design proposed in the paper can satisfy the requirement of the possible minimum atmosphere seeing at astronomical observatory site and exert the use efficiency of the telescope adequately. So the accuracy of the traditional surface of reflector can assure that 90% of all the light energy can be focused on within the angle diameter range of the minimum atmosphere seeing  then 100% of light energy should be focused on the angle diameter range of minimum atmosphere seeing. Because the rms of mirror is very high  precise surface machining and accurate the support of mirror are very important tasks during designing and manufacturing the telescope. In the paper  various support techniques of a large-aperture telescope primary mirror are discussed and a 3.5 meter telescope system at the Starfire Optical Range (SOR) overviewed simply  which was operated by the Directed Energy Directorate of the Air Force Research Laboratory  Kirtland AFB  NM  USA from the ground-based O-E system for the observations of spatial target. We also analyze Theoretical elastic deformation of the Steward Observatory 2.3 meter mirror is analyzed.