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Saline-alkali land classification using MODIS data in Western Jilin Province, China 会议论文  OAI收割
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：8/0  |  提交时间：2014/05/15
Study on spectrograph for ionosphere: A broadband imaging instrument prototype for far-ultraviolet (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
作者:  Wang S.-R.;  Lin G.-Y.;  Yu L.
收藏  |  浏览/下载：19/0  |  提交时间：2013/03/25
Current research on space-based exploration for the ionosphere needs more advanced technologies. Because the spectral signals in the ionosphere distributing basically in the far-ultraviolet waveband are very weak. Usual spectrometer structures and detectors such as CCD can't receive enough information. Based on this principle of atmospheric sounding  the imaging spectrometer prototype for ionosphere detection application was designed to solve the problem. This prototype consists of the telescope and the imaging spectrometer. The simple structure and small number of mirrors can help higher transmission efficiency be achieved and weak signals detection be implemented. The telescope is an off-axis parabolic mirror and the spectrometer is a modified Czerny-Turner spectral imaging system. Modified Czerny-Turner spectrometer contains a spherical mirror  a fixed plane grating and a toroidal mirror. By adjusting the incident angle to the collimating mirror and using toroidal mirror  coma and astigmatism were corrected well. We also optimize distances between the grating to the focusing mirror and the focusing mirror to the image plane to improve disadvantages of traditional Czerny-Turner structure. Designed results demonstrate that aberrations are substantially corrected  and high image quality can be obtained in broad waveband. The photon counting Wedge-Strip-Anode detector with micro-channel planes as the receiving plane is accepted for the instrument prototype. The other photon counting 2-D detector responding well for weak light such as Cross-Delay line detector and MAMA detector can also be used for detection. The calibration and performances testing system is made of a vacuum system  a deuterium lamp  a monochrometer and the instrument prototype. Results obtained from the experiment show that the spectral resolution is 2.4 nm and the spatial resolution is 80 m. The other calibration experiments are running. The technology of the spectrometer prototype is important for the research and applications of ionosphere remote sensing. 2011 SPIE.  
Level 0 and level 1 data processing for a type of hyper-spectral imager (EI CONFERENCE) 会议论文  OAI收割
2009 International Conference on Optical Instruments and Technology, OIT 2009, October 19, 2009 - October 21, 2009, Shanghai, China
Li X.; Yan C.
收藏  |  浏览/下载：62/0  |  提交时间：2013/03/25
Hyper-spectral imaging (HSI) is a kind of optical remote sensor that can simultaneously obtain spatial and spectral information of ground targets. We are now designing a data processing system for a type of space-borne push-broom HSI  then it performs radiometric and spectral calibration based on the ground calibration results and onboard calibration collection. The detailed algorithms for bad pixel replacement  which has 128 spectral channels covering the spectral range from 400nm to 2500nm. With its large amount of spectral channels  radiometric and spectral calibration were presented. After processing  the HSI collects large volume of spectral imaging data need to be efficiently and accurately processed and calibrated. In this paper  the digital numbers downlinked from the spacecraft can be converted into at-sensor absolute spectral radiance of ground targets  the detailed Level 0 and Level 1 data processing steps for the HSI were presented. The Level 0 processing refers to a set of tasks performed on the data downlinked from the spacecraft  thus providing accurate quantified spectral imaging data for various applications. 2009 SPIE.  including decoding to extract science data  separating the science data into files corresponding to different tasks (e.g. ground imaging  dark imaging  and onboard calibration)  checking data integrity and instrument settings  data format conversion  and Level 0 files creation. The Level 1 processing performs several steps on Level 0 data. Firstly  it corrects the image artifacts (mostly the SWIR smear effect)  subtracts the dark background  and performs the bad pixel replacement according to the prelaunch measurement