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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:20/0  |  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.  
Inspection focus technology of space tridimensional mapping camera based on astigmatic method (EI CONFERENCE) 会议论文
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, April 26, 2010 - April 29, 2010, Dalian, China
Wang Z.; Zhang L.
收藏  |  浏览/下载:16/0  |  提交时间:2013/03/25
The CCD plane of the space tridimensional mapping camera will be deviated from the focal plane(including the CCD plane deviated due to camera focal length changed)  under the condition of space environment and vibration  impact when satellite is launching  image resolution ratio will be descended because defocusing. For tridimensional mapping camera  principal point position and focal length variation of the camera affect positioning accuracy of ground target  conventional solution is under the condition of vacuum and focusing range  calibrate the position of CCD plane with code of photoelectric encoder  when the camera defocusing in orbit  the magnitude and direction of defocusing amount are obtained by photoelectric encoder  then the focusing mechanism driven by step motor to compensate defocusing amount of the CCD plane. For tridimensional mapping camera  under the condition of space environment and vibration  impact when satellite is launching  if the camera focal length changes  above focusing method has been meaningless. Thus  the measuring and focusing method was put forward based on astigmation  a quadrant detector was adopted to measure the astigmation caused by the deviation of the CCD plane  refer to calibrated relation between the CCD plane poison and the asrigmation  the deviation vector of the CCD plane can be obtained. This method includes all factors caused deviation of the CCD plane  experimental results show that the focusing resolution of mapping camera focusing mechanism based on astigmatic method can reach 0.25 m. 2010 Copyright SPIE - The International Society for Optical Engineering.  
A design on a control method of a new type of focal plane shutter (EI CONFERENCE) 会议论文
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Xue L.; Ming L.; Zheng L.-N.; Zhou J.-F.; Zhang H.-W.; Zhang J.-C.
收藏  |  浏览/下载:24/0  |  提交时间:2013/03/25
In order to ensure appropriate exposure time  and no exposure while electric charge is transferring after taking a photograph  it is necessary to have the shutter mechanism cooperate with CCD for area CCD aerial cameras. The ground object illumination has a wide range which is from 4000Lx to 100000Lx  so a shutter which is high efficient and a continuous stepless adjustment are also required. This paper introduces the fundamental principle  structural design and control procedure about this new focal plane shutter. Under the control of DSP  the velocity of shutter curtain governed by the shutter motor can be not only precisely controlled  but also the durability and the reliability are increased. The experiment results have shown that this new shutter has the higher stability of movement  long life span with more than 105 operating times  a wide range of exposure time from1/ 50s to 1/ 320s(depending on the slit width)and the exposure error is less than 10%. With the CCD gain adjustment  the performance of this shutter is fully satisfied with the requirements of area CCD aerial cameras. 2010 IEEE.  
Modeling of satellite borne TDI CCD pitching imaging image motion velocity vector (EI CONFERENCE) 会议论文
2009 IEEE International Conference on Automation and Logistics, ICAL 2009, August 5, 2009 - August 7, 2009, Shenyang, China
Zhang L.; Li S.; Jin G.; Yang X.
收藏  |  浏览/下载:12/0  |  提交时间:2013/03/25
In order to obtain three-dimensional observation effect with single satellite borne time delay and integrate charge coupled device (TDI-CCD)  pitching imaging is required. More accurate real-time image motion velocity vector computational model of space camera is also necessary to make the imaging perfect. Imaging motion velocity vector computation model must be set up on image plane at pitching imaging. According to the geometric relationship between the pitching imaging space camera and the Earth's rotation motion  satellite borne TDI CCD pitching imaging motion velocity vector model is derived by mapping the ground speed to the image plane and using coordinate transformation method. The numerical simulation results show that the image velocity model can reduce deviation angle error about 33' and about 30% image motion speed error compared to traditional ground velocity model. 2009 IEEE.  
Resolution performance of extreme ultraviolet telescope (EI CONFERENCE) 会议论文
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 19, 2008 - November 21, 2008, Chengdu, China
Gao L.; Yang L.; Li D.-S.; Ni Q.-L.; Liang J.-Q.; Chen B.
收藏  |  浏览/下载:20/0  |  提交时间:2013/03/25
Extreme Ultraviolet Telescope (EUT) will image solar corona in four EUV narrow bandpasses defined by multilayered coatings deposited on normal incidence optics. In order to make sure it will get sub-arcsecond angular resolution in the mission we have to test its resolution performance on ground. The EUT is aligned by Zygo interferometer first and a global wavefront error of 0.152 peak to valley is obtained ( = 632.8nm ). Because of the difficulty of angular resolution test for EUT at its operating wavelengths  we test its optical performance at visible and UV band. The method is to place the resolution test-target on the focal plane of collimator and illuminate the target by visible and UV light espectively  then the collimated light will go through EUT and image at focal plane on CCD. By analysis of the images obtained in experiments we conclude that the angular resolution of EUT is 1.22 at visible light ( = 570nm ) which is very close to diffraction limit (1.20) and according to these results we estimate that the operational wavelength resolution is better than 0.32  meets design requirements. While for UV light  the angular resolution is 1.53 that is different from diffraction limit (0.53)  the error comes mainly from large pixel of EUV camera. 2009 SPIE.  


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