中国科学院机构知识库网格系统: 检索

Toward Accurate and Efficient Road Extraction by Leveraging the Characteristics of Road Shapes 期刊论文 OAI收割
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, 2023, 卷号: 61, 页码: 16
作者: Wang, Changwei; Xu, Rongtao; Xu, Shibiao; Meng, Weiliang; Wang, Ruisheng

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收藏 | 浏览/下载：14/0 | 提交时间：2023/11/17

Efficient and accurate road extraction efficient strip transformer module (ESTM) geometric deformation estimation module (GDEM) road edge focal loss (REF loss) road shape-aware network (RSANet)

Local difference-based active contour model for medical image segmentation and bias correction 期刊论文 OAI收割
IET Image Processing, 2019, 卷号: 13, 期号: 10, 页码: 1755-1762
作者: Niu, Yuefeng; Cao, Jianzhong

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收藏 | 浏览/下载：69/0 | 提交时间：2019/09/25

image segmentation medical image processing two-phase model medical images LBDE model precise segmentation results comparative models local difference-based active contour model medical image segmentation bias correction local bias field difference estimation model smooth orthogonal basis functions clustering criterion function measured image local region accurate segmentation results level set evolution process

Local difference-based active contour model for medical image segmentation and bias correction 期刊论文 OAI收割
IET IMAGE PROCESSING, 2019, 卷号: 13, 期号: 10, 页码: 1755-1762
作者: Niu, Yuefeng; Cao, Jianzhong

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收藏 | 浏览/下载：26/0 | 提交时间：2020/06/05

image segmentation medical image processing two-phase model medical images LBDE model precise segmentation results comparative models local difference-based active contour model medical image segmentation bias correction local bias field difference estimation model smooth orthogonal basis functions clustering criterion function measured image local region accurate segmentation results level set evolution process

Using three-band model to retrieve chlorophyll-A of Yantai coastal waters 会议论文 OAI收割
Ocean Remote Sensing and Monitoring from Space, Beijing, China, October 15, 2014 - October 16, 2014
Ma, Wandong(1); Wu, Chuanqing(1); Yin, Shoujing(1); Zhu, Li(1); Wu, Di(1); Xing, Qianguo(2)

收藏 | 浏览/下载：61/0 | 提交时间：2015/08/10

Remote sensing Accurate estimation Band model Chlorophyll a Chlorophyll-a concentration Coastal waters Determination coefficients Linear relationships Medium resolution imaging spectrometers

A Fast and Highly Accurate Carrier Acquisition for Deep Space Applications 会议论文 OAI收割
5th International Congress on Image and Signal Processing (CISP), Chongqing, PEOPLES R CHINA, OCT 16-18, 2012
作者: Wang, Le; Wang, Zhugang; Xiong, Weiming

收藏 | 浏览/下载：36/0 | 提交时间：2014/12/15

Frequency accurate estimation FFT Phase ML estimation estimation bias Functional invariance

Chirp estimation of PZT for integrating-bucket method (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: Zhang J.; Liu W.; Zhang J.; Zhang J.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

The nonlinear response of the PZT for the integrating bucket method is studied by our proposed method: discrete chirp Fourier transform (DCFT) and maximum likelihood estimation (MLE) techniques for the integrating bucket method. Based on the signal processing theory the intensity obtained from CCD is processed by the DCFT and thus nonlinear response and chirp coefficient of the PZT can be coarsely estimated. This is followed by the MLE method in which an iterative optimization process is complemented for accurately estimating the nonlinear response and chirp coefficient of the PZT. One key advantage of the proposed method is that not only the nonlinear response and chirp coefficient of the PZT can be acquired but also initial phase acquired. Our method is tested by simulating conditions under which a certain magnitude of nonlinearity is assumed. Nonlinear response attained by the DCFT is compared to that attained by the MLE and a difference between the actual nonlinear response of the PZT and our accurate estimation by the proposed method is revealed. Several factors that will have influence on the nonlinear response of the PZT are discussed. 2010 Copyright SPIE - The International Society for Optical Engineering.

Estimation algorithm of mobile OFDM CFOs based on step-size (EI CONFERENCE) 会议论文 OAI收割
2009 International Conference on Information Engineering and Computer Science, ICIECS 2009, December 19, 2009 - December 20, 2009, Wuhan, China
Lin L.; Qiao Y.-F.; Su W.-X.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

In order to maintain orthogonality among subcarriers for mobile OFDM a CFOs step-size estimation model is established to avoid severe performance degradation caused by ICI and algorithmic stability step-size parameter the error of CFOs estimate and etc are investigated. First after an averaging window algorithm is introduced the mathematic model of step-size estimation algorithm is obtained through step-size parameter and time-varying CFOs. Then based on the results of MATLAB simulation the determination of step-size parameter the advantages of step-size algorithm and precision are discussed. Finally time sequence plots of added CP interleaver and subcarrier modulation with VHDL are presented. Experimental results indicate that the maximum of CFOs errors is 0.00987 in 3 variance interval when mobile velocity is 400 km/h according with verdicted principle that in order for the ICI effects to be negligible the error of CFOs estimation must be accurate within 1-2% of the subcarrier spacing and programs can correctly implement on circuit board. 2009 IEEE.

Remote chlorophyll-a retrieval in eutrophic inland waters by concentration classification Taihu Lake case study 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
Du, Cong; Wang, Shixin; Zhou, Yi; Yan, Fuli

收藏 | 浏览/下载：32/0 | 提交时间：2014/12/07

In order to improve the precision of phytoplankton chlorophyll-a (chla) concentration retrieval this study classified the data into two groups (the high and the low) by chla concentration with the threshold of 50gA&bullL-1. And then build the statistical models for each group. Particularly a modifying factor OSS/TSS was used to unmixing the spectra in the low model to improve the low relationship between spectral reflectance and chla concentrations. As a result the concentration classification model allowed estimation of chla with a root mean square error (RMSE) of 21.12gA&bullL-1 and the determination coefficient (R2) was 0.92 comparing with RMSE of chla estimation was 35.72gA&bullL-1 and R2=0.72 in the traditional model. It shows that concentration classification is a helpful method for accurate remote chla retrieval in eutrophic inland waters. 2008 SPIE.

Application of CMOS APS star tracker with large FOV in attitude and angular velocity determination (EI CONFERENCE) 会议论文 OAI收割
Advanced Sensor Systems and Applications III, November 12, 2007 - November 14, 2007, Beijing, China
Lu D.; Guang J.; Shaoju W.; Tao C.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

The paper deals with the spacecraft attitude determination problem using a new kind of star tracker with large FOV based on CMOS APS. Star tracker has been developed since 1970s and proved to be the most accurate sensor ever used in the spacecraft attitude determination systems. But the traditional CCD star tracker also has some disadvantages such as small FOV high power consumption low sample rate and low working angular rate limit which prevent the use of CCD star tracker in attitude large angle maneuvering process. The new kind of star tracker based on CMOS APS has no such disadvantages and is more applicable on modern low-cost agile small satellites. Its higher sample rate and working angular rate limit over traditional CCD star tracker make it more adapt for spacecraft angular velocity determination. Because of the large FOV of the star tracker the mathematical model of traditional CCD star tracker with a small FOV is not appropriate. So a new mathematical model was quoted to fit the star tracker with a large FOV. An alternative adaptive algorithm was also introduced in the paper. It can help the EKF algorithm work lacking of accurate covariance of the observation noise. An optimal estimation algorithm was used to estimate the angular velocity directly from the star tracker measurements. Mathematic simulation results indicate the CMOS APS star tracker can give accurate attitude information and estimated angular rate. The method can be used as the chief attitude determination system design of low-cost satellite without gyros or be used as a backup strategy in the event of gyro failures to enhance the reliability of the attitude determination system.

Study on color difference estimation method of medicine biochemical analysis (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: Zhou Y.; Zhou F.; Wang C.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

The biochemical analysis in medicine is an important inspection and diagnosis method in hospital clinic. The biochemical analysis of urine is one important item. The Urine test paper shows corresponding color with different detection project or different illness degree. The color difference between the standard threshold and the test paper color of urine can be used to judge the illness degree therefore it can be used in hospital so that further analysis and diagnosis to urine is gotten. The color is a three-dimensional physical variable concerning psychology the estimation method of color difference in urine test can have better precision and facility than the conventional test method with one-dimensional reflectance calibrating organization and family while reflectance is one-dimensional variable it can make an accurate diagnose. The digital camera is easy to take an image of urine test paper and is used to carry out the urine biochemical analysis conveniently. On the experiment so its application prospect is extensive. the color image of urine test paper is taken by popular color digital camera and saved in the computer which installs a simple color space conversion (RGB &rarr XYZ &rarr L*a*b*) and the calculation software. Test sample is graded according to intelligent detection of quantitative color. The images taken every time were saved in computer and the whole illness process will be monitored. This method can also use in other medicine biochemical analyses that have relation with color. Experiment result shows that this test method is quick and accurate