中国科学院机构知识库网格系统: 检索

The state of the art for liquid crystal adaptive optics in astronomical applications (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
作者: Liu Y.; Liu Y.; Xuan L.; Liu Y.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

In this paper we summarize the researches of liquid crystal (LC) adaptive optics(AO) in astronomical applications. Dual frequency and nematic LC materials were reported to be used in astronomical observations. However nematic LC with its simple producing and driving method and multi-gray-level is promising in the application. We have investigated the nematic LC AO system and promoted its application for nearly ten years. Here we reported our newest nematic LC AO system with bandwidth result of 3dB is 54.4 Hz 0dB bandwidth is 79.1Hz. 2012 IEEE.

Evaluation of spatial upscaling methods based on remote sensing data with multiple spatial resolutions (EI CONFERENCE) 会议论文 OAI收割
Satellite Data Compression, Communications, and Processing VIII, August 12, 2012 - August 13, 2012, San Diego, CA, United states
Ren R.; Gu L.; Cao J.; Chen H.; Sun J.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

In most applications of remote sensing data special spatial information is required from a finer to a coarser spatial resolution with appropriate upscaling methods. The purpose of this paper is to compare and evaluate current spatial upscaling methods using MODIS remote sensing data with multiple spatial resolutions. In the research Northeast China was selected as the study area. MODIS data with spatial resolutions of 250 m (2 bands) and 500 m (7 bands) were used as the test data. Through using the selected upscaling methods the Band 1 and Band 2 data of MODIS were scaled up from 250 m to 500 m spatial resolution. On the basis of land cover characteristics of Northeast China the MODIS data located in the study area was classified into the five land cover types including water grasslands forests farmlands and bare lands using maximum likelihood method. The land cover classification results were further compared with MODIS Land Cover Type product. Finally Structural Similarity (SSIM) was selected to evaluate the effects of these upscaling methods. The research can provide more useful information for spatial scaling transformation in remote sensing data applications. 2012 SPIE.

Realization of auto-focusing system for cameras based on TMS320F2812 DSP (EI CONFERENCE) 会议论文 OAI收割
2nd Annual Conference on Electrical and Control Engineering, ICECE 2011, September 16, 2011 - September 18, 2011, Yichang, China
作者: Zhang T.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

Focusing systems play an important role in a variety of optical measurements and detection instruments. In this paper several kinds of auto-focusing methods were described and the relevant focusing evaluation functions were introduced based on image processing methods. An auto-focusing system based on image processing was designed by using the TMS320F2812 digital signal processing chip as a platform. Moreover some problem and solutions about auto-focusing system was demonstrated. The system designed in this paper can find the good image plane in 10 steps (about 5 second) thus it can meet the requirements of practical applications. 2011 IEEE.

Image compression algorithm of high-speed SPIHT for aerial applications (EI CONFERENCE) 会议论文 OAI收割
2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011, May 27, 2011 - May 29, 2011, Xi'an, China
作者: Zhang K.; Zhang K.; Zhang K.; Zhang K.

收藏 | 浏览/下载：39/0 | 提交时间：2013/03/25

SPIHT and NLS (Not List SPIHT) are efficient compression algorithms but the algorithms application is limited by the shortcomings of the poor error resistance and slow compression speed in the aviation and other areas requiring high-speed compression. In this paper the error resilience and the compression speed are improved. The remote sensing images are decomposed by Le Gall5/3 wavelet and wavelet coefficients are indexed scanned and allocated by the means of family blocks. The bit-plane importance is predicted by bitwise OR so the N bit-planes can be encoded at the same time. Compared with the SPIHT algorithm this modified algorithm is easy implemented by hardware and the compression speed is improved. The PSNR of reconstructed images encoded by high-speed SPIHT is slightly lower than SPIHT at rate 1bpp but the speed is 4.5-6 times faster than SPIHT encoding process. The algorithm meets the high speed and reliability requirements of aerial applications. 2011 IEEE.

Surface modification of SiC mirror by IARE method (EI CONFERENCE) 会议论文 OAI收割
7th International Conference on Thin Film Physics and Applications, September 24, 2010 - September 27, 2010, Shanghai, China
作者: Gao J.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

A method to prepare high quality SiC coating at low temperature using large aperture E-beam evaporation PVD equipment with ion assistance was developed for the surface modification of SiC mirror for space projects. This method was called Ion Assisted Reactive Evaporation (IARE). The modified SiC coating was prepared using CH4 and Si with Kaufman ion source by IARE at 300C and it had met the requirements of applications. The SiC coating prepared by this method was amorphous. It was dense homogeneous and easy to be polished. The surface modification of a SiC mirror was carried out using SiC coating by this method and achieved a fine surface modification effect. The surface roughness (rms) of the SiC substrate was reduced to 0.862nm the scattering coefficient was reduced to 2.79% and the reflectance coated with Ag film was improved simultaneously after the surface modification. The effect of surface modification using SiC coating was close to that of using Si coating. It can be drawn that this technological method to preparation SiC coating for the surface modification of SiC mirror is reasonable and effective. 2011 SPIE.

Study on image real-time interpretation based on particle filter (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
作者: Liu S.-J.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

In order to satisfy to the real-time requirement of image interpretation system in photoelectric measurement equipments a kind of hardware acceleration system with MIMD distributed multi-processor architecture based on SOPC technology is designed. The particle filter algorithm is proposed to process image interpretation for state estimation problem of nonlinear and non-Gaussian system. This algorithm does not involve conventional linearization transform and has approximated the posterior probability density by a set of discrete particles. Therefore the approximate optimum result is educed. It has a high accuracy and a rapid convergence. Experimental results show that the algorithm be adequate to real time accuracy and robustness meets the requirement of image interpretation and possesses practical significance for engineering applications. 2011 IEEE.

Citizen-generated spatial data and information: Risks and opportunities 会议论文 OAI收割
2011 IEEE International Conference on Intelligence and Security Informatics, ISI 2011,, Beijing, China, July 10, 2011 - July 12,2011
Mooney, Peter; Sun, Huabo; Corcoran, Padraig; Yan, Lei

收藏 | 浏览/下载：20/0 | 提交时间：2014/12/07

The use of location-enabled mobile technology is ubiquituos. We outline the opportunities and risks involved in using user-generated spatial data and information. User generated spatial data is a very dynamic but has many inconsistencies. This could severely limit its use in many security and intelligence applications. 2011 IEEE.

Non-uniformity correction in multi-CCD imaging system (EI CONFERENCE) 会议论文 OAI收割
2010 2nd International Conference on Mechanical and Electronics Engineering, ICMEE 2010, August 1, 2010 - August 3, 2010, Kyoto, Japan
Tao M.; Ren J.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

The non-uniformity phenomenon exists in each channel of multi-CCD imaging systems. The factors which lead to the problem are complex. The conventional calibrating algorithms can not consider all of these factors and have poor effects. According to the characters of multi-CCD imaging systems a non-uniformity correction method based on the scene was proposed by adopting the traditional two-point correction theories. The correction coefficient of each channel image can be calculated via the linear relation between the two neighboring pixel lines in the two-channel images. Compared with the conventional two-point calibration and multi-point calibration methods contrastive calibrating results were obtained. This method does not need any standard lighted image as reference source which provides a real time way for calibrating the multi-CCD imaging systems in practical applications. 2010 IEEE.

Design of image interpretation and data-processing system based on SOPC (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Wang Z.-Q.; Liu Z.-R.; Xie M.-J.

收藏 | 浏览/下载：14/0 | 提交时间：2013/03/25

In order to follow the development of image interpretation and data-processing system in photoelectric measurement equipments a kind of hardware acceleration system is designed where MIMD distributed multi-processor architecture is used with SOPC technology. System hardware is composed of FPGA SDRAM SRAM FLASH and PCI bridge chip. Four Nios II embedded processors are integrated in a single FPGA chip and communicate with each other by sharing memory. Experimental results indicate that the system meets the requirements of data-processing system in photoelectric measurement equipments and possesses practical significance for engineering applications. 2010 IEEE.

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：74/0 | 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