中国开放科研知识云: 检索

Design of the real-time autofocusing system for collimator with long focus length and large aperture (EI CONFERENCE) 会议论文
2011 International Academic Conference on Numbers, Intelligence, Manufacturing Technology and Machinery Automation, MAMT 2011, December 24, 2011 - December 25, 2011, Wuhan, China
Li X.; Zhang X.

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Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment the large aperture collimator's accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However the process of adjusting the collimator is extremely complicated due to the collimator's large aperture and long focal length. So it is difficult to ensure the measurement's quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror semiconductor lasers as light source and CCD sensor as receiver. The system is smaller lighter and more convenient when using. The computer simulation shows that the autofocusing system's resolution could reach the accuracy of 40m. If we use the relevant algorithms to execute the sub-pixel scanning the resolution could reach the accuracy of 10m. It shows that the system could satisfy the required testing precision of testing large aperture optical device.

Moving target detection and classification using spiking neural networks (EI CONFERENCE) 会议论文
2nd Sino-Foreign-Interchange Workshop on Intelligent Science and Intelligent Data Engineering, IScIDE 2011, October 23, 2011 - October 25, 2011, Xi'an, China
Cai R.; Wu Q.; Wang P.; Sun H.; Wang Z.

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We proposed a spiking neural network (SNN) to detect moving target in video streams and classify them into real categorization in this paper. The proposed SNN uses spike trains to encoding information such as the gray value of pixels or feature parameters of the target detects moving target by simulating the visual cortex for motion detection in biological system with axonal delays and classify them into different categorizations according to their distance to categorization's centers found by Hebb learning rule. The experimental results show that the proposed SNN is promising in intelligence computation and applicable in general visual surveillance system. 2012 Springer-Verlag.

Design of heliostats field for the scale of 1MW solar power tower plant (EI CONFERENCE) 会议论文
2012 Asia-Pacific Power and Energy Engineering Conference, APPEEC 2012, March 27, 2012 - March 29, 2012, Shanghai, China
Zhang H.; Wang Z.; Wei X.; Lu Z.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

The development in basic technology and market strategy of solar thermal power techniques is booming rapidly due to the limited fossil resources and severe environmental problems all over the world. In this paper the design method of heliostats field for the scale of 1MW solar power tower plant with latitude of 40.4N at the design point of the noon of spring equinox is introduced which uses the multiplication of three efficiencies of cosine atmospheric transmittance and intercept as the preliminary boundary limit to locate heliostats while the spacing between heliostats is set not only for less shading and blocking but also for the availability of installation and maintenance of heliostats. Furthermore its optical performance tested by the software HFLD is quite good which has annual average efficiency of 71.36% and design point efficiency of 80%. 2012 IEEE.

Lightweight design and analysis of support structure of certain UAV engine (EI CONFERENCE) 会议论文
2012 International Conference on Electrical Insulating Materials and Electrical Engineering, EIMEE 2012, May 25, 2012 - May 27, 2012, Shenyang, Liaoning, China
Xing X.; Liu B.; Han X.; Jia H.

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Support structure of UAV (Unmanned Aerial Vehicle) engine is the important support for UAV engine playing a support role and bearing extremely complex load so its lightweight strength and dynamic characteristics have a great influence on high performance of UAV. This paper focuses on UAV having the requirement of high performance and stability to the support structure of engine and uses the software of MSC.Patran and MSC.Nastran and topology optimization criterion to lightweight design and analysis the support structure of UAV engine under the premise condition of existing constraints. Then the static strength and modal are analyzed for the result of lightweight design and the strength of the model and dynamic characteristics are verified. (2012) Trans Tech Publications Switzerland.

Reentry guidance based on feedback linearization (EI CONFERENCE) 会议论文
2011 International Conference on Electronics, Communications and Control, ICECC 2011, September 9, 2011 - September 11, 2011, Ningbo, China
Li D.-W.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

This paper presents a new reentry guidance algorithm for RLV (Reusable Launching Vehicle). The algorithm consists of two integrated components: trajectory planning algorithm and tracking algorithm. The most striking feature of algorithm here lies in that both planning and tracking are executed directly in height-velocity space which is different from the methodology of configuration of drag in traditional shuttle guidance. In the session of trajectory planning all trajectory constraints can be expressed with upper bound and lower bound in height-velocity space then a linear interpolation is carried to search the nominal trajectory satisfying the requirement of downrange and target constraints. Then the tracking algorithm uses feedback linearization method to track this nominal profile and meet all constraints. Another typical feature of this algorithm is the strategy of downrange extension using FPA (flight path angle) controller to fulfill the requirement of large downrange. Proper combination of planning-tracking algorithm and FPA controller can bring great flexibility and adaptability to reentry guidance. The algorithm is proved to be robust enough to accommodate the model error and noises in the dynamics. 2011 IEEE.

Design for target classifier based on semi-supervised learning (EI CONFERENCE) 会议论文
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China
Jiangrui K.

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The target classifier is an ingredient of the target recognition system. In order to achieve the automation and computerization of target recognition a method for training target classifier based on semi-supervised learning is provided. It adopts CFS algorithm for dada feature selection and uses semi-supervised learning algorithm Co-training to construct the target classifiers. The final classifier was produced through integration learning method. Experimental results show that the performance of the target classifier based on semi-supervised learning trained is superior to the traditional target classifier. 2011 IEEE.

The design of analog video data grabber system based on TMS320VC33 and SAA7111A (EI CONFERENCE) 会议论文
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
Geng T.-W.; Wang Z.-Q.; Liu S.-J.; Li D.-N.; Yu S.-B.

收藏 | 浏览/下载：11/0 | 提交时间：2013/03/25

Analog video data grabber system based on TMS320VC33 and SAA7111A is proposed for a kind of automatic optical alignment measuring device. System uses the enhanced video processing chip SAA7111A to complete A/D conversion. The function of SAA7111A and the register configuration method of I2C Bus are introduced in the paper. System uses FPGA to control video data grabber and collaborative work of DSP. DSP processes video data. The paper gives design method of hardware and software. Experimental results indicate that the system can satisfy the requirements. 2011 IEEE.

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.

Fabrication of high-efficiency ultraviolet blazed gratings by use of direct Ar2-CHF3 ion-beam etching through a rectangular photoresist mask (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Sensor and Micromachined Optical Device Technologies, May 24, 2011 - May 26, 2011, Beijing, China
Tan X.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

In ultraviolet spectroscopy groove irregularity and surface roughness of nanometer magnitude can cause a significant loss of diffraction efficiency. Therefore there is a constant need to improve the diffraction efficiency. A blazed grating can concentrate most of the light intensity into a desired diffraction order it is important to control the groove shape precisely so it is the optimum choice among gratings of different kinds of profile. As the operating wavelength of most UV spectral applications is less than 200 nm especially the blaze angle and the apical angle. We have presented a direct shaping method to fabricate EUV blazed gratings by using an ion-beam mixture of Ar+ and CHF2 +to etch K9 glass with a rectangular photoresist mask. With this method the required blaze angle is small we have succeeded in fabricating well-shaped UV blazed gratings with a 1200 line/mm groove density and 8.54 blaze angles and 1200 line/mm groove density and 11.68 blaze angles and the metrical efficiency is about 81% and 78%. The good performance of the gratings was verified by diffraction efficiency measurements. When one uses the etching model the conditions on the ion-beam grazing incident angle and the CHF3partial pressure should be noted. Besides since the etched groove shape depends on the aspect ratio of the photoresist mask ridge if we wish to fabricate larger gratings with this method we must improve the uniformity of the photoresist mask before ion-beam etching. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Design and analysis of auto-focus assembly for spaceborne remote sensing camera (EI CONFERENCE) 会议论文
2011 International Conference on Electronics, Communications and Control, ICECC 2011, September 9, 2011 - September 11, 2011, Ningbo, China
Chen W.; Ding Y.; Hui S.; Gao X.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

Spaceborne remote sensing camera may be out of focus when the environment and photographic distance changes. In order to get higher ground sampled distance for the camera based on the experience gained from the development of a remote sensing camera working principle of auto-focus assembly control system was discussed. Time of waveform extraction was reduced. It sets force an auto-focus assembly that uses cam and line guide rail in order to move the lens group. The motion error of the auto-focus assembly was difficult to be eliminated and would affect on the focusing accuracy of the spaceborne remote sensing camera directly. So it was analyzed at both ends of the focusing structure. The CCD detector can keep stable when the remote sensing camera is imaging. The motion error was tested to verify the validity of the simulation result and it is less than 0.01mm. Its accuracy meets using demand. The focusing method of moving focal plane is suitable for spaceborne remote sensing camera. 2011 IEEE.

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