2014
2014
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Record 229 of
Title:Error correction of photoelectric rotary and angle encoder
Author(s):Zhou, Liang(1,2); She, Wen-Ji(1); Huang, Jing(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9142 Issue: DOI: 10.1117/12.2054092 Published: 2014Abstract:The photoelectric rotary and angle encoder is a digital angle measuring device, which is integrated with optics, mechanics and electrics. Because of its simple structure, high resolution, and high accuracy, it has been widely used in precision measurement of angle, digital control and digital display system. With the needs of fast tracking and accurate orientation on the horizon and air targets, putting forward higher requirements on accuracy of angle measurement and resolution of photoelectric rotary and angle encoder. Influences of manufacturing, electronics segmentation, optical and mechanical structure and eccentric shaft to photoelectric encoder precision and reducing methods are introduced. Focusing on the eccentricity error, building up an error correction model to improve the resolution of angle encoder and the model was verified by test. ? 2014 Copyright SPIE.Accession Number: 20141217474340 -
Record 230 of
Title:Laser spectrum detection methods for substance of Mars surface
Author(s):Zhang, Dan(1,2); Xue, Bin(1); Zhao, Yi-Yi(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9298 Issue: DOI: 10.1117/12.2070682 Published: 2014Abstract:The chemical element and mineral rock's abundance and distribution are the basic material of planetary geology evolution research[1], hence preterit detection for composition of Mars surface substance contains both elements sorts and mineral ingredients. This article introduced new ways to detect Mars elements and mineral components, Laser Induced Breakdown Spectroscopy (LIBS) and Raman Spectroscopy (RS) which have distinct advantages, such as work over a long distance, detect rapidly, accuratly and nondestructively. LIBS and RS both use laser excitation to shoot the substance of Mars exciting new wavelengths. The techniques of LIBS and RS in laboratory are mature, besides the technique of LIBS is being used in MSL (Chemcam) now and RS will be used in ExoMars. Comparing LIBS and RS's detection results with XRF and APXS, Mossbauer spectrometer, these existed Mars surface material detection instruments,and the Infrared spectrometer, Mid-IR, they have more accurate detection results. So LIBS and RS are competent for Mars surface substance detection instead of X-ray spectrometer and Mossbauer spectrometer which were already used in 'Viking 1' and 'Opportunity'. Only accurate detection results about Mars surface substance can lead to scientist's right analysis in inversing geological evolution of the planet. ? 2014 SPIE.Accession Number: 20150800546090 -
Record 231 of
Title:Design of midwave infrared athermalization optical system with a large focal plane array
Author(s):Shen, Mande(1); Li, Cheng(1); Ren, Huanhuan(1); Jiang, Qinxiu(1); Chen, Liangyi(2)Source: Optik Volume: 125 Issue: 13 DOI: 10.1016/j.ijleo.2013.12.024 Published: July 2014Abstract:Based on the most advanced staring focal plane array which had a format of 640 × 480 and the pixel pitch of 15 μm, a set of all-sphere midwave infrared ahermalization optical system was designed. The working wavelength was in 3-5 μm, the full field of view was 8.58°, the relative aperture was 1/2, the efficient focal length (EFL) was 80 m. The opticalsystem consisted of four lenses with three kinds of material - Ge, ZnSe and Si. All surfaces were sphere, which was easier to process test, making the cost inexpensive, and it could avoid using diffractive surface and aspheric surface. The image quality of the system approaches the diffraction limit in the temperature range -60 °C-180 °C. The design results proved that, the high resolution midwave infrared optical system had compact structure, small volume, high resolution and excellent image quality, meeting the design requirements, so that it could be used for photoelectric detection and tracking system.Accession Number: 20142317798003 -
Record 232 of
Title:Rytov variance equivalence through extended atmospheric turbulence and an arbitrary thickness phase screen in non-Kolmogorov turbulence
Author(s):Zeng, Zhihong(1,2); Luo, Xiujuan(1); Xia, Aili(1); Zhang, Yu(1,2); Sun, Chuangdong(1)Source: Optik Volume: 125 Issue: 15 DOI: 10.1016/j.ijleo.2014.01.106 Published: August 2014Abstract:An arbitrary thickness phase screen model can describe scintillation index for Gaussian beam propagating through a phase screen more accurate than thin phase screen model. To describing actual scintillation index for Gaussian beam propagating through an extended medium using a phase screen in weak non-Kolmogorov turbulence, the scintillation index and Rytov variance for arbitrary thickness phase screen model are derived. Specially, the ratio of the Rytov variances for a phase screen and extended random media is found under the assumption of equivalence in scintillation index of the two cases. The theoretical results show that the normalized Rytov variance varies with the power law of the turbulence spectrum, the relative thickness of the phase screen, the position of the phase screen, the transmitter beam parameters and the radial position at output plane. The influences of these variables are also simulated. These results will be applied to simulation of adaptive optics and laser communication. ? 2014 Elsevier GmbH.Accession Number: 20143017989336 -
Record 233 of
Title:Four dimensional spectral imager with integral field fiber bundle
Author(s):Li, Libo(1,2); Feng, Yutao(1); Wang, Shuang(1); Bai, Qinglan(1); Hu, Bingliang(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 34 Issue: 5 DOI: 10.3788/AOS201434.0511004 Published: May 2014Abstract:As one of the most important development of remote sensing, spectral imager has been widely used in military, geognosy, ocean and atmosphere measurement. However, the classic spectral imager, neither dispersive spectral imager nor Fourier transform spectrometer, which has to take multiple exposures to scan spectral data cube, do not suit with the situation that the scene change too fast. Four-dimensional (4D) fiber reformatting spectral imager, in which a special optical fiber bundle sits in the image plane of the telescope and has linearly aligned at the entrance to the spectrograph, can capture three-dimensional (3D) spectral data cube in a single exposure. So it enable to measure fast moving target or fast changing scene. A breadboard system in the laboratory is described, the average spectral resolution of the system is 4.2 nm in visible range, and a good imaging result of color target is got. The fiber bundle errors are analyzed, and the calibrating method is given.Accession Number: 20142217774436 -
Record 234 of
Title:A secondary mirror adjustment system with hexapod structure for optical telescope application
Author(s):Zhou, Nan(1,2); Li, Chuang(1); Gao, Wei(1); Song, Zong Xi(1); Zhao, Chao(1,2); Ren, Guo Rui(1,2); Jing, Nan(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9280 Issue: DOI: 10.1117/12.2068311 Published: 2014Abstract:Benefiting from low cost, light weight and reduced volume in launch, deployable optical telescopes will be extensively applied in microsatellites. As a result of manufactured tolerance and external disturbance, the secondary mirror can't arrive at designed position precisely after a deployable telescope is unfolded. We investigate an adjustment system with six degrees of freedom based on hexapod structure to solve this problem. There are mainly four parts in this paper. Firstly, the adjustment methods of deployable telescopes for microsatellites are introduced. Generally several kinds of optical components can be adjusted to align a deployed telescope: primary mirror, tip/tilt mirror and secondary mirror. Due to its high sensitivity and convenience, the secondary mirror is chosen to collimate the optical system of the telescope. Secondly, an adjustment system with hexapod structure is designed for a secondary mirror with 85 mm diameter. After comparing the characteristics of step motors, piezo actuators and voice coil motors (VCMs), VCMs are selected as the linear actuators. By using optical gratings as displacement sensors in the system, we can make closed-loop control come true. The hexapod structure mainly consists of 6 VCMs, 6 optical gratings and 6 oblique legs with flexible hinges. The secondary mirror adjustment system is 83 mm in diameter and 55 mm high. It has tip/tilt rotational ranges of ±2.205° with resolution of better than ±0.007°, and translational ranges of ±1.545 mm with resolution of better than ±0.966 μm. Thirdly, the maximum stress and the maximum deformation in the adjustment system are computed with finite element method. At last, the kinematics problems of the adjustment system are discussed. ? 2014 SPIE.Accession Number: 20150800541538 -
Record 235 of
Title:Design of space optical system with double infrared waveband based on image space scanning
Author(s):Li, Gang(1,2); Fan, Xuewu(1); Zou, Gangyi(1,2); Wang, Hongjuan(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 3 DOI: Published: March 2014Abstract:The design of optical systems with wide ground coverage are restricted by the size of infrared detector. This problem can be solved by choosing the appropriate imaging mode. A kind of image space scanning method was given in the paper. It could satisfy the optical systems with general area infrared detectors. The picture was built by image mosaics technology. Because the image space scanning method needs to be done in the parallel light path, the design method of three-mirror afocal system was studied based on two-mirror afocal system and the formulas to compute the initial structure was given. The optical system consists of afocal system, scanning mirror and imaging part. The scanning mirror was placed at the exit pupil of the afoacl system. The MWIR and LWIR were separated by the field-bias method and imaged respectively. The simulation analysis shows that the Narcissus is under control and the MTF of the optical system is very close to the diffraction limit.Accession Number: 20142217774735 -
Record 236 of
Title:Influence of magnetic solenoid lens on characteristics of streak image tube
Author(s):Liu, Rong(1,2,3); Tian, Jinshou(1); Wang, Qiangqiang(1,2); Wang, Chao(1); Wen, Wenlong(1); Lu, Yu(1); Liu, Hulin(1); Cao, Xibin(1); Wang, Junfeng(1); Zhao, Wei(1)Source: Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology Volume: 34 Issue: 10 DOI: 10.13922/j.cnki.cjovst.2014.10.11 Published: October 1, 2014Abstract:The magnetic field in the pole piece magnetic lens of a new type of femto-second (fs) streak image tube with both high temporal and spatial resolution was re-modeled to improve the precision. The influence of the magnetic solenoid lens on the magnetic field distribution and on the temporal and spatial resolution characteristics of the streak image tube was investigated. The magnetic field distributions, generated by the magnetic lens with different radius ratios, were simulated with Lorentz software; and the emission and trajectories of up to 3000 photoelectrons were sampled and calculated in Monte Carlo method with software CST PARTICLE STUDIO to statistically evaluate the temporal and spatial resolution of the image tube with the modulation transfer function. The simulated results show that the Gaussian model outperforms the bell-shaped model when it comes to description of the realistic magnetic field, and that the magnetic lens with a radius ratio of 0.83 most effectively focuses the electron beam with a temporal resolution of 190 fs and a spatial resolution over 100 lp/mm.Accession Number: 20144800253454 -
Record 237 of
Title:A multispectral image fusion algorithm based on the HIS space and improved wavelet
Author(s):Duan, Zewei(1,2); Wen, Desheng(1); Song, Zongxi(1)Source: Journal of Information and Computational Science Volume: 11 Issue: 6 DOI: 10.12733/jics20103220 Published: April 10, 2014Abstract:In order to optimize the multispectral image fusion, the paper proposes a fusion method based on HIS space and improved wavelet. The new method maps the multispectral image to HIS space and acquires components of intensity, hue and saturation. In addition, an improved wavelet algorithm is applied on the fusion of the intensity of multispectral image and the panchromatic image, the algorithm can both consider the fusion method of low-frequency and high-frequency sub-bands: On the low-frequency subband aspect, the paper introduces a border detector operator in order to collect the border information of images that can be the basis of selective fusion method; On the high-frequency sub-band aspect, it applies local-standard-deviation to be the basis of selective and weighted-averaging fusion method. Ultimately, the new HIS components obtain fusion result through reverse transformation. The experiment reveals that the result acquired by this method can improve on the quality of spectral information and spatial information. ? 2014 Binary Information Press.Accession Number: 20141917704048 -
Record 238 of
Title:Effect of space environment on working life of solid-lubricated rotating parts
Author(s):Shangguan, Ai-Hong(1,2); Mu, You(1); Li, Zhi-Guo(1); Liu, Zhao-Hui(1)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 22 Issue: 12 DOI: 10.3788/OPE.20142212.3264 Published: December 1, 2014Abstract:To explore the effect of space environment on the working life of solid-lubricated rotating parts and forecast their working life in orbit, the influence of space environment on solid-lubricated films was analyzed. The analysis points out that three main factors are relative to the working life of the space rotating parts, which are space launch environment, vacuum degree and alternating temperature. A life test was designed to simulate the three factors, in which the mechanical test was used to simulate space launch environment, and the thermal vacuum test was taken to simulate the vacuum and alternating temperature. The X-ray Energy Dispersive Spectrometer (EDS) was used to analyze the film composition of the unworn race and the worn race for a bearing in the solid-lubricated rotating part as well as ball surface materials. The analysis results show that the transfer film has not formed. On the result, it forecasts that the working life of the solid-lubricated rotating part in the test would be up to 107 times. Finally, it gives some necessary suggests that should been taken to increase the reliability and improve the work life of space rotating parts. ?, 2014, Chinese Academy of Sciences. All right reserved.Accession Number: 20150400441441 -
Record 239 of
Title:Visual simulation for space-telescope by coordinate transform
Author(s):Cui, Kai(1,2); Liu, Zhaohui(1); Li, Zhiguo(1,2); Liang, Dongsheng(1,2); Yuan, Hui(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 2 DOI: Published: February 2014Abstract:Visual simulation is useful for designing, analyzing and testing a space-telescope on the ground. Based on the coordinate transformation theory and the equal-angle projection method, visible boundary of the telescope was deduced for different orientation, and the two-dimension visual simulation was carried out using a real star catalog and the world coast line data. Reasonable results show that when the space-telescope is pointing to the high latitude area, a distortion of the round visible boundary appears in the Equidistant Cylindrical Projection style map chart. And the visible area on the earth surface is expanded when the height of the space-carrier increases. The simulation was used to imitate the celestial background in a real testing of a space-telescope outdoor. It's useful in testing and providing space environment for space-telescope on the ground.Accession Number: 20141317523538 -
Record 240 of
Title:Misalignment induced aberration characteristic of Cassegrain telescope
Author(s):Pang, Zhihai(1,2); Fan, Xuewu(1); Ma, Zhen(1); Chen, Qinfang(1); Zou, Gangyi(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 1 DOI: Published: January 2014Abstract:Based on the vector wavefront aberration theory, the misalignment induced aberration' s characteristic of Cassegrain optical system was analyzed in this paper. It is shown that a misaligned Cassegrain has three residual 3rd aberrations. The 3rd order spherical aberration is constant over the field and the 3rd order coma increases linearly with the field but the zero coma point no longer locates at the field center. Moreover, the astigmatism aberration field in system without symmetric contains two zero astigmatism point, neither of which is necessarily located on the field center of view. It has been demonstrated that a Cassegrain under assembly is only measured to have perfect performance on-axis but not aligned in any significant way, so the measurements of multiple field points for the Cassegrain are required in the process of alignment.Accession Number: 20141017420267