中国科学院机构知识库网格系统: 检索

Real-time BDS signal-in-space anomaly detection method considering receiver anomalies 期刊论文 OAI收割
IET RADAR SONAR AND NAVIGATION, 2019, 卷号: 13, 期号: 12, 页码: 2220-2229
作者: Fan, Lihong; Tu, Rui; Zhang, Rui; Zheng, Zengji; Liu, Jinhai

|

收藏 | 浏览/下载：32/0 | 提交时间：2021/11/29

satellite navigation astronomical ephemerides telecommunication network reliability signal detection signal-in-space user range error SIS URE real-time navigation positioning users real-time SIS anomalies location services BeiDou satellites user range accuracy index navigation ephemeris anomaly detection threshold real-time observation data receiver anomalies BeiDou Navigation Satellite System MultiGlobal Navigation Satellite System Experiment precise ephemeris detection results real-time BDS signal-in-space anomaly detection method IURE international GNSS Monitoring & Assessment System

An accurate multislice method for low-energy transmission electron microscopy 期刊论文 OAI收割
MICRON, 2012, 卷号: 43, 页码: 374-379
作者: Cai, Canying; Chen, Jianghua

|

收藏 | 浏览/下载：23/0 | 提交时间：2018/07/05

Image Simulation Multislice Method Real Space Method High-energy Approximation

Adaptive Wiener filtering with Gaussian fitted point spread function in image restoration (EI CONFERENCE) 会议论文 OAI收割
2011 IEEE 2nd International Conference on Software Engineering and Service Science, ICSESS 2011, July 15, 2011 - July 17, 2011, Beijing, China
作者: Yang L.; Zhang X.; Zhang X.; Zhang X.; Yang L.

收藏 | 浏览/下载：41/0 | 提交时间：2013/03/25

In the imaging process of the space remote sensing camera there was degradation phenomenon in the acquired images. In order to reduce the image blur caused by the degradation the remote sensing images were restored to give prominence to the characteristic objects in the images. First the frequency-domain notch filter was adopted to remove strip noises in the images. Then using the ground characters with the knife-edge shape in the images the point spread function of the imaging system was estimated. In order to improve the accuracy the estimated point spread function was corrected with Gaussian fitting method. Finally the images were restored using the adaptive Wiener filtering with the fitted point spread function. Experimental results of the real remote sensing images showed that almost all strip noises in the images were eliminated. After the denoised images were restored its variance and its gray mean gradient increased also its laplacian gradient increased. Restoration with Gaussian fitted point spread function is beneficial to interpreting and analyzing the remote sensing images. After restoration the blur phenomenon of the images is reduced. The characters are highlighted and the visual effect of the images is clearer. 2011 IEEE.

Design and demonstration of micro multi-step mirrors and light source in micro FTIR (EI CONFERENCE) 会议论文 OAI收割
6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, NEMS 2011, February 20, 2011 - February 23, 2011, Kaohsiung, Taiwan
Liang Z.; Fu J.; Feng C.; Liang J.

收藏 | 浏览/下载：41/0 | 提交时间：2013/03/25

To obtain high resolution high signal-to-noise ratio (SNR) high reliability and real time in wide spectral range we study the space modulation Micro Fourier Transform Spectrometer (FTS) based on multi-step mirrors covering the spectral range of 3-5m and 8-12 m in theory and experiment. The influences of spectrum reconstruction caused by the diffraction and extended light source in Fourier Transform Infrared Spectrometer (FTIR) are analyzed. A method to reduce the noises in spectrum reconstruction and the relationship between coherent intensity and solid angle of light source are discussed. An extended light source with suitable size is chosen considering the requirement of SNR and spectrum resolving power in the optical design. Furthermore the fabrication of micro multi-step mirrors which is the core part of FTS is investigated. Three methods for fabricating multi-step micro mirrors are demonstrated. 2011 IEEE.

Dynamic closed-loop test for real-time drift angle adjustment of space camera on the Earth (EI CONFERENCE) 会议论文 OAI收割
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
作者: Xu S.; Wang D.

收藏 | 浏览/下载：35/0 | 提交时间：2013/03/25

In order to eliminate the influence of aircraft attitude angle to the image quality of space camera and assure that the drift angle of space camera could be accurately adjusted at the orbit a novel closed-loop test method is provided for real-time drift angle adjustment of space camera on the Earth. A long focal length dynamic aim generator is applied to simulate the image motion and the variety drift angle and to detect the precision of the image motion compensation machinery and the capability of the drift angle control system. The computer system is used to control the dynamic aim generator accomplish the data processing transmit and receive the data information. The seamless connection and the data transmission between the aim generator and the aircraft simulation devices are constituted. The command parameter and drift angle data transmitted by the simulation devices are received by the space camera at the real time then the photos are taken and the draft angle is adjusted simultaneously. It is shown that the drift angle can be accurately tracked by the space camera at the real time and the detective method satisfies the test requirement. 2010 Copyright SPIE - The International Society for Optical Engineering.

Method for obtaining real temperature of space object by using the ratio of emissivity at different wavelengths (EI CONFERENCE) 会议论文 OAI收割
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
Guo-Qiang W.; Tao C.; Jian-Li W.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

The infrared radiation character (temperature and efficiency radiation area) of a space object is an important characteristic we can judge the state of the object working in orbit by measuring temperature and variety. Due to lower temperature of the object and far distance between the object and the earth the infrared radiation signal is faintness therefore temperature and the infrared radiation character is difficult to measure. There are several methods to measure the temperature of the object in theory and each one has its applicability respectively such as applying Wien Law to compute temperature based on Stefan-Bolzmann law to compute temperature and utilizing multi-spectrum detector to measure temperature As a whole these methods are based on the hypothesis that the object is a Black-body or the radiance emissivity is constant. In fact homochromatic radiance of object is not a constant but a function that changes with wavelength. Since the problem that an object whose homochromatic radiance s not a constant which results in temperature can not be computed accurately we bring forward a method to contrast the luminance of the object at different wavelengths and deduce the relationship among homochromatic radiance and wavelength and the temperature of Black-body from which we can compute real temperature of object. 2009 SPIE.

Modeling of satellite borne TDI CCD pitching imaging image motion velocity vector (EI CONFERENCE) 会议论文 OAI收割
2009 IEEE International Conference on Automation and Logistics, ICAL 2009, August 5, 2009 - August 7, 2009, Shenyang, China
作者: Zhang L.; Li S.; Zhang L.

收藏 | 浏览/下载：14/0 | 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.

Study on color model conversion for camera with neural network based on the combination between second general revolving combination design and genetic algorithm (EI CONFERENCE) 会议论文 OAI收割
ICO20: Illumination, Radiation, and Color Technologies, August 21, 2005 - August 26, 2005, Changchun, China
作者: Li Z.; Zhou F.; Wang C.; Li Z.

收藏 | 浏览/下载：36/0 | 提交时间：2013/03/25

Munsell color system is selected to establish the mutual conversion between RGB and L*a*b* color model for camera. The color luminance meter and CCD camera synchronously measure the same color card XYZ value is gotten from the color luminance meter the training error is 0.000748566 it can show that the method combining second general revolving combination design with genetic algorithm can optimize the hidden-layer structure of neural network. Using the data of testing set to test this network and calculating the color difference between forecast value and true value the color picture captured from CCD camera is expressed for RGB value as the input of neural network and the L*a*b* value converted from XYZ value is regarded as the real color value of target card which the difference is not obvious comparing with forecast result the maximum is 5.6357 NBS namely the output of neural network. The neural network of two hidden-layers is considered the minimum is 0.5311 NBS so the second general revolving combination design is introduced into optimizing the structure of neural network and the average of color difference is 3.1744 NBS. which can carry optimization through unifying project design data processing and the precision of regression equation. Their mathematics model of encoding space is gained and the significance inspection shows the confidence degree of regression equation is 99%. The mathematics model is optimized by genetic algorithm optimization solution is gotten and function value of the goal is 0.0007168. The neural network of the optimization solution is trained

A segment detection method based on improved Hough transform (EI CONFERENCE) 会议论文 OAI收割
ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China
作者: Yao Z.-J.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

Hough transform is recognized as a powerful tool in shape analysis which gives good results even in the presence of noise and the disconnection of edge. However 3. applying the standard Hough transform equation to every point of the input image edge 4. according to the local threshold 6. merging the segments whose extreme points are near. Experiment results show the approach not only can recognize regular geometric object but also can extract the segment feature of real targets in complex environment. So the proposed method can be used in the target detection of complicated scenes traditional Hough transform can only detect the lines 2. quantizing the parameter space and extracting a group of maximums according to the global threshold eliminating spurious peaks which are caused by the spreading effects and will improve the precision of tracking. cannot give the endpoints and length of the line segments and it is vulnerable to the quantization errors. Based on the analysis of its limitations Hough transform has been improved in order to detect line segment feature of targets. The algorithm aims to avoid the loss of spatial information as well as to eliminate the spurious peaks and fix on the line segments endpoints accurately 5. fixing on the endpoints of the segments according to the dynamic clustering rule which can expediently be used for the description and classification of regular objects. The method consists of 6 steps: 1. setting up the image parameter and line-segment spaces

Image simulation for non-orthogonal crystal system by real space method 期刊论文 OAI收割
ACTA METALLURGICA SINICA, 2001, 卷号: 37, 期号: 10, 页码: 1009-1012
作者: Liu, QX; Yang, QB; Wang, YM; Du, K

|

收藏 | 浏览/下载：7/0 | 提交时间：2021/02/02

real-space method image simulation non-orthogonal crystal system