中国科学院机构知识库网格系统: 检索

Elevation-Dependent Trends in Himalayan Snow Cover (2004-2024) Based on MODIS Terra Observations 期刊论文 OAI收割
REMOTE SENSING, 2025, 卷号: 17, 期号: 18, 页码: 25
作者: Tauqir, Ghania; Zhao, Wei; Xu, Mengjiao; Fu, Dongjie

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收藏 | 浏览/下载：0/0 | 提交时间：2025/11/06

snow-covered areas elevation-dependent snow dynamics altitudinal variations pixel-based analysis climate variability

Elevation-Dependent Trends in Himalayan Snow Cover (2004-2024) Based on MODIS Terra Observations 期刊论文 OAI收割
REMOTE SENSING, 2025, 卷号: 17, 期号: 18, 页码: 3175
作者: Tauqir, Ghania; Zhao, Wei; Xu, Mengjiao; Fu, Dongjie

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收藏 | 浏览/下载：1/0 | 提交时间：2025/11/17

snow-covered areas elevation-dependent snow dynamics altitudinal variations pixel-based analysis climate variability

Automatic chessboard corner detection method 期刊论文 OAI收割
IET IMAGE PROCESSING, 2016, 卷号: 10, 期号: 1, 页码: 16-23
作者: Liu, Yu; Liu, Shuping; Cao, Yang; Wang, Zengfu

收藏 | 浏览/下载：33/0 | 提交时间：2018/01/25

Cameras Calibration Edge Detection Statistical Analysis Automatic Chessboard Corner Detection Method Chessboard Pattern-based Camera Calibration Technique Hessian Corner Detector Fake Corner Elimination Sub-pixel Location Statistical Approach Computational Efficiency

Comparison and simulation of subpixel imaging modes for linear CCD (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Information Technology for Manufacturing Systems, ITMS 2012, September 8, 2012 - September 9, 2012, Qingdao, China
作者: Li Y.; He B.; Li Y.; Li Y.; Li Y.

收藏 | 浏览/下载：67/0 | 提交时间：2013/03/25

Subpixel technique of linear CCD is effective to enhance the spatial resolution without increasing the focal length of optics and reducing the pixel size. To compare image quality of two main subpixel imaging modes quincunx sampling and four-point sampling a method to quantitatively evaluate image quality of subpixel based on MTF was proposed. The MTF of quincunx and four-point sampling modes were derived. Analytical results shows that theoretical limiting resolution of quincunx sampling and four-point sampling is improved to 1.4 and 1.86 times respectively and MTF values at Nyquist frequency of two modes are increased by 0.1106 and 0.1679 respectively. MTFA in (0 0.5) of two subpixel imaging modes were calculated and results illustrates that four-point sampling offers much more improvement with image quality than quincunx sampling at the cost of double amount of data. A model for simulating subpixel imaging using Matlab was established and simulation results of spoke target verify the theoretical analysis. (2012) Trans Tech Publications Switzerland.

Evaluation of the operating range for ground-based infrared imaging tracking system (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者: Zhang Z.-D.

收藏 | 浏览/下载：65/0 | 提交时间：2013/03/25

Ground-based infrared imaging tracking system (GIITS) is of great importance for aerial target warning and guard. The operating range is one of the key performance specifications on the other which should be calculated calculate the radiation power received on the detector in order to analysis whether the output signal meets the detection requirements or not analyzed and studied during the whole GIITS design process. The operating range is mostly influenced by a few factors without considering the effect of the background radiation. By improving of the traditional method including atmospheric attenuation a new operating range calculation model of the GIITS was established based on two requirements. One is that the image size of observed target should meet the requirement of the processor signal extraction. The number of the pixel occupied by target image should be more than 9. The other is that the signal noise ratio (SNR) of the GIITS should not be less than 5 to meet the requirements of the target detection probability and spatial frequency. The SNR calculation equation in form of energy is deduced and the radiation characteristic of the observed target and background are analyzed. When evaluate the operating range of the GIITS using the new method the performance of GIITS and feature of target and background. This paper firstly makes analysis and summarization on the definite localizations of the traditional operating range equation of the GIITS. The localizations are mainly in two aspects. On one hand we should successively calculate two operating range values according to two requirements mentioned above and choose the minimum value as the analytic result. In the end the dispersion of the image and the effect of image dispersion are not considered in the traditional method an evaluation of operating range for fighter aircraft is accomplished as an example. The influence factors in every aspect on operating range were explored by the calculated result. The new operating range calculation model provides the theoretical basis for the design and applications as well as the comprehensive evaluation of a GIITS. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Study on dynamic imaging on TDI CCD optical remote sensor of push-broom technology (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: Liu L.; Ren J.-Y.; Liu L.; Gao M.-H.

收藏 | 浏览/下载：36/0 | 提交时间：2013/03/25

A set special detecting system is proposed based on TDICCD push-broom technology applying in dynamic imaging detecting experiment of space optics remote sensor. In the system In the course of detecting push-broom movement of the satellite is simulated through using double supporting U structure precision rotary platform with remote sensor by angular speed 0.555/s regard Nyquist frequency target as detecting aim within the range of 5 and control precision on steady speed achieves 0.3% in order to solve matching uncertainty between the CCD pixel and the vertical target strip image when the remote sensor does push-broom make matching simplify enhance the measurement result the accuracy. So the tolerance a/n arithmetic progression gap target strip is joined in each group of rectangular vertical group target strip. The remote sensor obtains in vertical the level and 45 the direction 0 fields of view 0.86 the field of view Nyquist frequency target strip image after detected a group target strip which can precision matching to TDICCD pixel at least can be obtained through analysis and dealing with 0.86 field of view's target strip image. The experiment not only verifies the detecting system's feasibility but simultaneously verifies whether to have the high quality dynamic imaging quality when TDICCD push-broom technology is adopted on the remote sensor developed. 2010 Copyright SPIE - The International Society for Optical Engineering.

Improved best tradeoff for high-resolution image fusion based on spectral reflection function 会议论文 OAI收割
International Conference on Earth Observation Data Processing and Analysis, ICEODPA,, Wuhan, China, December 28, 2008 - December 30,2008
Wang, Zhongwu; Zhao, Zhongming

收藏 | 浏览/下载：51/0 | 提交时间：2014/12/07

This paper extended the best tradeoff fast intensity-hue-saturation (BTFIHS) fusion to a more general model. Firstly based-on the methods proposed by previous researches we integrated injecting strategy of spatial detail information into the fusion model and also adopted the idea of BTFIHS to keep the intensity unchanged with the corresponding pixel in panchromatic (PAN) image while the hue and saturation of every pixel using BTFIHS were equal to them using tradeoff fast intensity-hue-saturation (TFIHS). Then we got a general formula of the improved best tradeoff for high-resolution image fusion based-on getting injecting parameter by spectral reflection function (SRF). At last several experiments were carried on to analysis and discuss the quality of the new methods compared with their originals. Results show that the new method could yield a "true" high-resolution multispectral (MS) image with vast improvement in blue band and nearly 3.3% improvement in Q4 for all bands. 2008 SPIE.

Target track system design based on circular projection (EI CONFERENCE) 会议论文 OAI收割
ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China
Song H.-J.; Zhu M.; Hu S.; Shen M.-L.

收藏 | 浏览/下载：39/0 | 提交时间：2013/03/25

Template matching is the process of searching the present and the location of a reference image or an object in a scene image. Template matching is a classical problem in a scene analysis: given a reference image of an object decide whether that object exists in a scene image under analysis and find its location if it does. The template matching process involves cross-correlating the template with the scene image and computing a measure of similarity between them to determine the displacement. The conventional matching method used the spatial cross-correlation process which is computationally expensive. Some algorithms are proposed for this speed problem such as pyramid algorithm but it still can't reach the real-time for bigger model image. Moreover the cross-correlation algorithm can't be effective when the object in the image is rotated. Therefore the conventional algorithms can't be used for practical purpose. In this paper an algorithm for a rotation invariant template matching method based on different value circular projection target tracking algorithm is proposed. This algorithm projects the model image as circular and gets the radius and the sum of the same radius pixel value. The sum of the same radius pixel value is invariable for the same image and the any rotated angle image. Therefore this algorithm has the rotation invariant property. In order to improve the matching speed and get the illumination invariance the different value method is combined with circular projection algorithm. This method computes the different value between model image radius pixel sum and the scene image radius pixel sum so that it gets the matching result. The pyramid algorithm also is been applied in order to improve the matching speed. The high speed hardware system also is been design in order to meet the real time requirement of target tracking system. The results show that this system has the good rotate invariance and real-time property.

Chip design of linear CCD drive pulse generator and control interface (EI CONFERENCE) 会议论文 OAI收割
2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies - Advanced Optical Manufacturing and Testing Technologies, November 2, 2005 - November 5, 2005, Xian, China
作者: Sun H.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：49/0 | 提交时间：2013/03/25

CCD noises and their causes are analyzed. Methods to control these noises such as Correlated Double Sampling (CDS) filtering cooling clamping and calibration are proposed. To improve CCD sensor's performances the IC called Analog Front End (AFE) integration of CDS clamping Programmable Gain Amplifier (PGA) offset and ADC which can fulfill the CDS and analog-to-digital conversion is employed to process the output signal of CCD. Based on the noise control approaches the idea of chip design of linear CCD drive pulse generator and control interface is introduced. The chip designed is playing the role of (1) drive pulse generator for both CCD and AFE and (2) interface helping to analysis and transfer control command and status information between MCU controller and drive pulse generator or between global control unit in the chip and CCD/AFE. There are 6 function blocks in the chip designed such as clock generator for CCD and AFE MCU interface AFE serial interface output interface CCD antiblooming parameter register and global control logic unit. These functions are implemented in a CPLD chip Xilinx XC2C256-6-VQ100 with 20MHz pixel frequency and 16-bit high resolution. This chip with the AFE can eliminate CCD noise largely and improve the SNR of CCD camera. At last the design result is presented.

Geometrical modulation transfer function of different active pixel of CMOS APS (EI CONFERENCE) 会议论文 OAI收割
2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 2, 2005 - November 5, 2005, Zian, China
作者: Li J.; Liu J.; Liu J.; Liu J.; Li J.

收藏 | 浏览/下载：59/0 | 提交时间：2013/03/25

The geometrical Modulation Transfer Function (MTF) of CMOS APS (active pixel sensor) is analyzed in this paper. Advanced APS have been designed and fabricated where different pixel shapes such as square rectangle and L shape were placed because the amplifier circuit and other function circuits inter pixel of APS take up some pixel area. MTF is an important figure of merit in focal plane array imaging sensors. Research on analyzing the MTF for the proper pixel shape is currently in progress for a centroidal configuration of a target position. MTF will give us a more complete understanding of the tradeoffs opposed by the different pixel designs and by the signal processing conditions. Based on image sensor sampling and reconstructing model the MTF expression of any active pixel shape has been deduced in this paper. According to actual pixel shape three different active area pixels were analyzed they were square rectangle and L shape their Fill Factor (FF) is 30% 44% and 55% respectively. Results of simulation experiments indicate that different pixel geometrical characteristics contribute significantly to the figures of their MTF. Different geometrical shape of active sensitive area of pixel and different station in pixel would influence MTF figures. The analysis results are important in designing better APS pixel and more important in analyzing imaging system performance of APS subpixel precision system.