中国开放科研知识云: 检索

The openloop liquid crystal adaptive optics for astronomical application 会议论文
6th IFAC Symposium on Mechatronic Systems, MECH 2013, April 10, 2013 - April 12, 2013, Hangzhou, China
作者: Xuan L.; Zhang X.

收藏 | 浏览/下载：16/0 | 提交时间：2014/05/15

Saline-alkali land classification using MODIS data in Western Jilin Province, China 会议论文
Satellite Data Compression, Communications, and Processing IX, August 26, 2013 - August 27, 2013, San Diego, CA, United states
Gu L.; Ren R.; Cao J.; Sun J.

收藏 | 浏览/下载：9/0 | 提交时间：2014/05/15

Image mosaic technique based on the information of edge (EI CONFERENCE) 会议论文
2012 3rd International Conference on Digital Manufacturing and Automation, ICDMA 2012, July 31, 2012 - August 2, 2012, Guilin, Guangxi, China
Wu Z.-G.; Wang M.-J.; Wang Y.-Q.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

Image mosaic is an important branch in the field of image processing. This paper designs and realizes an image mosaic technique based on the information of edge. The technology is suitable for engineering application. First of all two images of the adjoining frames are processed by convolution operation get the edge images. And then we cut edge image into pieces and compute their spatial frequency. According to the value of the spatial frequency select reasonable registration model group. We compute correlation strength and the value of movement offset which are the model group and the current frame edge image. We can complete image mosaic by them. We use video sequence which of the resolution is 1024 * 768 do the experiment. The results show that the method has good effect and strong adaptability. Algorithm is high efficiency which running time is 24 ms. It is suitable for real-time processing requirements of the application. This method is an effective mosaic technique which is suitable for engineering application. 2012 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.

收藏 | 浏览/下载：34/0 | 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.

Simulation and experiment of the static FTIR based on micro multi-step mirrors (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
Liang J.; Liang Z.-Z.; Lv J.-G.; Fu J.-G.; Zheng Y.; Feng C.; Wang W.-B.; Zhu W.-B.; Yao J.-S.; Zhang J.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

In recent years Fourier transform spectrometer (FTS) with small size and low mass is required in many applications with growing need for real-time and small platform spectral detection. In this paper a micro Fourier transform infrared spectrometer (FTIR) based on spatial modulation mode was designed. This spectrometer has the advantages of high stability and simplified configuration. It also promises optical path differences (OPD) with high precision as MOEMS technology is used in manufacturing the key components. The simulation and the experiments with regard to this FTIR configuration have been done. Firstly the diffraction effect of the micro multi-step mirrors (MMSMs) is studied. We discuss the influence to the reversed spectrum by different mirror widths and different diffraction distances. Secondly we simulate and analyze the influence of the source solid angle to the spectral resolution. Thirdly we set up the theoretical model of the collimation error which is mainly from the defocus of the optical system and analyze the result caused by the collimation error. Fourthly a new discrete Fourier transform arithmetic using least-squares cosines progression (LSCP) is proposed which can reconstruct the spectrum with nonuniform sampled signals. Finally the MMSMs are fabricated used the MOEMS technology and the structural parameters are tested. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Research on radiometric calibration of interline transfer CCD camera based on TDI working mode (EI CONFERENCE) 会议论文
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
Wu X.-X.; Liu J.-G.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

Interline transfer CCD camera can be designed to work in time delay and integration mode similar to TDI CCD to obtain higher responsivity and spatial resolution under poor illumination condition. However it was found that outputs of some pixels were much lower than others' as interline transfer CCD camera work in TDI mode in laboratory radiometric calibration experiments. As a result photo response non-uniformity(PRNU) and signal noise ratio(SNR) of the system turned for the worse. This phenomenon's mechanism was analyzed and improved PRNU and SNR algorithms of interline transfer CCD camera were advanced to solve this problem. In this way TDI stage was used as a variant in PRNU and SNR algorithms and system performance was improved observably with few influences on use. In validation experiments the improved algorithms was applied in radiometric calibration of a camera with KAI-0340s as detector. Results of validation experiments proved that the improved algorithms could effectively improve SNR and lower PRNU of the system. At the same time characteristic of the system could be reflected better. As working in 16 TDI stages PRUN was reduced from 2.25% to 0.82% and SNR was improved about 2%. 2010 Copyright SPIE - The International Society for Optical Engineering.

Panoramic aerial camera image motion measurement using a hybrid system (EI CONFERENCE) 会议论文
2010 3rd IEEE International Conference on Computer Science and Information Technology, ICCSIT 2010, July 9, 2010 - July 11, 2010, Chengdu, China
Li G.; Jia P.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

Image motion compensation is significantly important for aerial camera photograph. To execute the compensation we must determine the image motion exactly. This paper proposes a method of real-time image motion measurement for panoramic aerial cameras based on image processing using a hybrid system. Two cameras are simultaneously used in the hybrid system. One main linear CCD for imaging while the other auxiliary low resolution high frame rate area CCD for determining the image motion based on 2D spatial correlation. The demanding computational requirements for the real-time 2D spatial correlation are covered by a joint transform optical correlator. Simulation test results show that the accuracy is improved and the measurement error is within 0.2 pixels for input images with SNR=1 dB. 2010 IEEE.

Research on the support structure of the primary mirror of large-aperture telescope (EI CONFERENCE) 会议论文
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：22/0 | 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.

A new spaceborne compression approach for remote sensing imagery (EI CONFERENCE) 会议论文
ICO20: Remote Sensing and Infrared Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
Xu X.; Dong G.; Feng Y.; Xu S.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

After analyzing advantages and disadvantages of these typical encoding methods: SPIHT and VQ a "DWT+MRLE" approach for spaceborne data compression was proposed in this paper. This approach includes two steps: Discrete Wavelet Transform (DWT) and Modified Run Length Encoding (MRLE). The former used CDF9/7 biorthogonal wavelet filters to powerfully get rid of correlation between pixels in imagery. The later put enlightening information into the lowest bit of some key-position transform coefficients. Consequently CDF9/7 and MRLE together make hardware platform remain high real-time capability and help reconstructed images keep good fidelity with PSNR being about 40dB compared with the original ones. Comparison between experimentations on SPOT4's low-spatial-resolution (10m) imagery and Ikonos2's high-spatial-resolution (1m) imagery shows this "DWT+MRLE" method having better performance for remote-sensed imagery especially those of higher resolution. Although inferior to 8:1 Compression Ration (CR) here near 5:1 is greater than France SPOT5's 3:1 and American Ikonos2's 11:2.6 on-board data compression. More important this method having less computational amount is good for spaceborne capability of real time. The consumed time of different image size is also presented in this paper based on TI TMSC6416 DSP chip with 600MHz CPU cycle clock.

A new method of image reconstruction with high resolution in X-ray coded aperture imaging (EI CONFERENCE) 会议论文
Laser-Generated, Synchrotron, and Other Laboratory X-Ray and EUV Sources, Optics, and Applications II, August 2, 2005 - August 4, 2005, San Diego, CA, United states
Hu J.; Cheng L.; Wu X.; Sun Y.; Bai Y.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

In the processing diagnosis of the inertia confinement fusion (ICF) the ring coded aperture imaging technique is applied in order to gain high space and time resolutions simultaneously. The key of acquiring high spatial resolution is how to obtain a point spread function of an imaging system. The common method is the firsthand projection method which is an approximate one. The x-ray diffraction effect is neglected in the method so the resolution of reconstructed image is decreased. We have derived the point spread function (PSF) of the ring coded aperture from scalar diffraction theory. And the Wiener filter is fabricated on the basis of the PSF. In National Key Laboratory of Laser Fusion at China Academy of Engineering Physics the imaging experiment on the diagnosis of ICF is completed using the ring coded aperture plate with inner diameter d1 = 250m and outer diameter d2 = 260m . The obtained coded image is processed by the Wiener filter which diffractive effect is considered. The processed results have shown that resolution and modulation contrast of acquired image are evidently better than the results obtained by the firsthand projection method.

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