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The system design and application of HY-2A scatterometer
Wang Xiaoning,Liu Lixia,Chen Wenxin
Strategic Study of CAE 2013, Volume 15, Issue 7, Pages 33-38
The HY-2A satellite was first launched in August of 2011,the microwave scatterometer as one of the main loads, is primarily applied in sea surface wind observation. HY-2A satellite scatterometer used two pencil beam circle scan system, and the radar worked in Ku band. The paper illuminates the scatterometer's system composition, main parameter, the in-orbit pretreatment and the results in observation to typhoon.
Keywords： HY-2A radar scatterometer backscattering coefficient calibration
An Ultrasonic Backscatter Instrument for Cancellous Bone Evaluation in Neonates Article
Chengcheng Liu,Rong Zhang,Ying Li,Feng Xu,Dean Ta,Weiqi Wang
Engineering 2015, Volume 1, Issue 3, Pages 336-343 doi: 10.15302/J-ENG-2015079
Ultrasonic backscatter technique has shown promise as a noninvasive cancellous bone assessment tool. A novel ultrasonic backscatter bone diagnostic (UBBD) instrument and an in vivo application for neonatal bone evaluation are introduced in this study. The UBBD provides several advantages, including noninvasiveness, non-ionizing radiation, portability, and simplicity. In this study, the backscatter signal could be measured within 5 s using the UBBD. Ultrasonic backscatter measurements were performed on 467 neonates (268 males and 199 females) at the left calcaneus. The backscatter signal was measured at a central frequency of 3.5 MHz. The delay (T1) and duration (T2) of the backscatter signal of interest (SOI) were varied, and the apparent integrated backscatter (AIB), frequency slope of apparent backscatter (FSAB), zero frequency intercept of apparent backscatter (FIAB), and spectral centroid shift (SCS) were calculated. The results showed that the SOI selection had a direct influence on cancellous bone evaluation. The AIB and FIAB were positively correlated with the gestational age (|R| up to 0.45, P < 0.001) when T1 was short (< 8 µs), while negative correlations (|R| up to 0.56, P < 0.001) were commonly observed for T1 > 10 µs. Moderate positive correlations (|R| up to 0.45, P < 0.001) were observed for FSAB and SCS with gestational age when T1 was long (> 10 µs). The T2 mainly introduced fluctuations in the observed correlation coefficients. The moderate correlations observed with UBBD demonstrate the feasibility of using the backscatter signal to evaluate neonatal bone status. This study also proposes an explicit standard for in vivo SOI selection and neonatal cancellous bone assessment.
Keywords： ultrasonic backscatter cancellous bone evaluation signal of interest (SOI) backscatter instrument neonatal bone status
HY-2A microwave scatterometer wind retrieval algorithm
Lin Mingsen,Zou Juhong,Xie Xuetong and Zhang Yi
Strategic Study of CAE 2013, Volume 15, Issue 7, Pages 68-74
The routine wind fields retrieval algorithm for China's microwave scatterometer onboard HY-2A (HY2-SCAT) was developed. By introducing a two-step search schema into the wind retrieval process, which included a coarse-search and an optimal-search, the efficiency of wind retrieval was greatly improved. Circular median filter was applied to remove the ambiguities, and the NCEP wind field was used as a background to re-initialized wind field consists of ambiguous wind vectors, so that the ambiguity removal skill can be largely enhanced. Wind vectors observed by HY2-SCAT were evaluated by comparison with NDBC buoy observations and ASCAT observations. The RMS difference was less than 2 m/s or less than 10 % for the comparison of wind speeds and the RMS difference was less than 20 degree for the comparison of wind direction, which indicated that the wind products provided by HY2-SCAT can meet the requirements for science and routine meteo users.
Keywords： HY-2A microwave scatterometer wind fields retrieval algorithm
cattering-absorbing method for the detection of 16.7 MeV high-energy pulsed gamma
Tan Xinjian,Ouyang Xiaoping,Wang Qunshu
Strategic Study of CAE 2009, Volume 11, Issue 8, Pages 48-51
This paper proposes a new method of diagnosing 16.7 MeV high-energy pulsed gamma, named "scattering-absorbing method" . The ratio of the sensitivity of HEG to that of the LEG can reach 106 to 108 by this new method. The sensitivity of 16.7 MeV high-energy gamma ranges from 10-21 to 10-16 C·cm2. It's better than the traditional method which bases on the magnetic analyzer and Cherenkov detector on some aspects.
Keywords： high-energy gamma Cherenkov detector scattering absorption method
Application of Wavelet Transform to Acoustic Radiation and Scattering
Wen Lihua,Ren Xingmin
Strategic Study of CAE 2002, Volume 4, Issue 8, Pages 63-68
Traditional boundary element methods with a full matrix equation for acoustic problems, have been met by a challenge in large-scale scientific computation and numerical simulation in engineering. In this paper, the new wavelet approaches have been presented for solving acoustic radiation and scattering, and structural-acoustic coupling. The boundary quantities are expanded in terms of a basis of the orthogonal wavelets on the interval, and a wavelet spectral formulation for solving acoustic problems is derived. Then coupled wavelet spectral and finite element method is formulated for solving sound-structure interaction. The advantages of the new approaches include a highly sparse matrix system which can be solved rapidly by sparse solvers and accurate modeling of curve surface. In the new technique, the iterative technique of frequencies is established for evaluating frequency-response functions through expanding the integral kernel in Taylor series in integral equation. The new technique was employed to investigate the underwater acoustic radiation from a complicate structure which is composed of shells, stiffening ribs and plates. The comparisons of the results from the new technique with analytic solution show that it has high computational efficiency and good accuracy.
At the end of the paper, the prospects of the application of wavelet analysis to numerical computation in acoustic engineering are discussed.
Keywords： wavelet analysis acoustic radiation and scattering structural-acoustic coupling frequency iteration
Study of Scattering Characteristic of Fire Smoke Based on Mie Theory
Shu Xueming,Fang Jun,Shao Quan,Yuan Hongyong
Strategic Study of CAE 2005, Volume 7, Issue 1, Pages 45-49
The scattering characteristic of fire smoke is a major aspect in fire smoke detection foundamental research. Based on Mie scattering theory, the paper presented some research on comparison between different algorithms. An improved algorithm was adopted to calculate the scattering intensity and its distribution in all directions. To verify the theoretical calculation results, a set of experiment was designed to measure the light intensity in three directions of different fire smoke. From the experiments results, it could be found that the results of calculation and experiment had a good accord. It can be concluded that the relative ratio of scattering intensity is an important parameter for certain material, and different kinds of smoke by this ratio.
Keywords： fire smoke Mie scattering algorithm relative ratio of scattering intensity
Research on the preprocessing of HY-2A space-borne scatterometer data
Zhang Yi,Lin Minseng,Song Qingtao,Xie Xuetong and Zou Juhong
Strategic Study of CAE 2013, Volume 15, Issue 7, Pages 62-67
This paper describes the key technologies involved in the scatterometer data preprocessing, which include the geometric positioning algorithm and the radar backscatter coefficient calculation algorithm. The geometric positioning of space-borne scatterometer data is a process of obtaining the coordination of measuring pulse, which needs to consider the instrument scan geometry, spatial location, antenna pointing, earth curvature, rotation, and other factors. The traditional method of geometric positioning of space-borne scatterometer data depends on the satellite ephemeris with a low positioning accuracy. HY-2A satellite is equipped with a global positioning system(GPS) sensor to provide the location of the satellite platform with 1 s interval. Accordingly, the geometric relationship between sensor observation and ground surface can be established. The geographic coordination of the observation cell center, observation azimuth angle and incidence angle can be determined using this geometric relationship. The radar backscatter coefficient is calculated with a parameter substitution method.
Keywords： HY-2A satellite microwave scatterometer preprocessing
De-scattering and edge-enhancement algorithms for underwater image restoration Research Papers
Pan-wang PAN, Fei YUAN, En CHENG
Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 6, Pages 862-871 doi: 10.1631/FITEE.1700744
Image restoration is a critical procedure for underwater images, which suffer from serious color deviation and edge blurring. Restoration can be divided into two stages: de-scattering and edge enhancement. First, we introduce a multi-scale iterative framework for underwater image de-scattering, where a convolutional neural network is used to estimate the transmission map and is followed by an adaptive bilateral filter to refine the estimated results. Since there is no available dataset to train the network, a dataset which includes 2000 underwater images is collected to obtain the synthetic data. Second, a strategy based on white balance is proposed to remove color casts of underwater images. Finally, images are converted to a special transform domain for denoising and enhancing the edge using the non-subsampled contourlet transform. Experimental results show that the proposed method significantly outperforms state-of-the-art methods both qualitatively and quantitatively.
Keywords： Image de-scattering Edge enhancement Convolutional neural network Non-subsampled contourlet transform
The study on oceanic vector wind field retrieve technique of the HY-2 satellite
Jiang Xingwei,Lin Mingsen
Strategic Study of CAE 2009, Volume 11, Issue 10, Pages 86-95
A retrieving oceanic vector wind algorithm and the precision analysis of its error in accordance with the HY-2 satellite's microwave scatterometer was put forward in the paper, and a technical process of data acquisition, pre-process, wind vector retrieve and production manufacture about the HY-2 satellite microwave scatterometer was also given. It will be ready on technology for making a due ontribution once the HY-2 satellite is launched and promotes our country's oceanic microwave remote sensing technique development.
Keywords： HY-2 satellite microwave scatterometer wind firld retrieve vector wind filed error analysis
Validation of wind vectors retrieved by the HY-2A microwave scatterometer using NC EP model data
Mu Bo,Lin Mingsen,Peng Hailong,Song Qingtao,Zhou Wu
Strategic Study of CAE 2014, Volume 16, Issue 6, Pages 39-45
The microwave scatterometer onboard HY-2A Satellite mainly makes measurements of surface wind vectors over the global oceans. In order to ensure that the quality of wind vectors produced by ground application system software,the product must be validated to provide the basis for the quantitative application of the data product.This paper performs the validation of wind vectorsretrieved by HY-2A scatterometer using national centers for environmental prediction (NCEP )model data. The validation result suggests that the validationmethod cangive the precision of the overall wind vectors, and also can be used to analyze the precision characteristics relating with thescanningpencil-beam system and the scatterometer measurement mechanism.Meanwhile the validation can aid to identify the short-term anomaly of measuring performance.
Keywords： microwave scatterometer windvectors inversion validation
Peng Hailong,Mu Bo,Lin Mingsen,Zhou Wu
Strategic Study of CAE 2014, Volume 16, Issue 6, Pages 33-38
The first Chinese dynamic environment satellites HaiYang-2A(HY-2A) satellite was successfully launched on August 16, 2011, with a Ku-band microwave scatterometer which can provide wind vector information of global ocean surface. The research results for all launched scatterometer in the Amazon rainforest region by the global scientists showed the variance of scatterometer backscatter coefficient measurements was less than 0.15dB with the season. According to this results, the analysis on HY-2A microwave scatterometer measurement data of the Amazon rainforest region in 2012—2013 have been finished, the results showed that HY-2A satellite scatterometer measurement performance onboard in 2012-2013 is very stable, which is consistent with the international research results that seasonal variation characteristic of HY-2A scatterometer measurements in the Amazon rainforest is less than 0.15dB.
Keywords： Amason rainforest HY-2A microwave scatterometer in-orbit measurement performance
Lin Mingsen,Zhang Yi,Song Qingtao,Xie Xuetong,Zou Juhong
Strategic Study of CAE 2014, Volume 16, Issue 6, Pages 46-53
HY-2 scatterometer is a spaceborne pencil-beam radar measuring the backscattering coefficient of ocean surface. Firstly, based on the description of the working mechanism and the principle of ocean surface wind retrieval from scatterometer data, quantitative analyses of some of the typhoons captured by HY-2 scatterometer in 2012 were carried out in this paper, that include location of the typhoon center, typhoon structure, path and the radius of maximum wind speed. Secondly, ocean surface wind field was overplayed on the meteorological cloud image acquired by FY-2E satellite to reveal the consistency of spatial structure of these two sources of data. Furthermore, ocean surface wind field from ASCAT was also used to make a contrast to the ocean surface wind field of HY-2 scatterometer. Multi-angle analysis has revealed the validity of ocean surface wind field observation and the advantages of typhoon monitoring by HY-2 scatterometer. Finally, the pros and cons of the HY-2 satellite microwave scatterometer were summarized, and the possible improvements of the HY-2 scatterometer were proposed in this paper.
Keywords： HY-2 satellite microwave scatterometer typhoon monitoring
Numerical Simulation of the Interaction Between Smoke and Water Mist in Fire
Ye Dong,Jiang Yong
Strategic Study of CAE 2007, Volume 9, Issue 2, Pages 84-89
This paper presents a numerical simulation of the interaction between smoke and water mist in a fire using CFD software package Fluent. Motion of droplets of different size in the flow field is studied and their fire extinguishing ability is compared according to whether they can reach the combustion zone. Scattering of thermal radiation from fire by water mist and the effects of breakup and coalescence of droplets at initial stage are also studied. Modeling results demonstrate that radiation is the main heat transfer process;bigger droplets are easier than smaller one to get away from the circumfluence zone and to arrive at the combustion zone. Water mist attenuates thermal radiation by absorbing and scattering, and it may enhance combustion reaction rate at initial stage. These results agree with experimental result.
Keywords： water mist Fluent thermal radiation scattering coalescence breakup
Study on Several Radio Propagation Models in ITU - R Recommendations
Zhang Minggao
Strategic Study of CAE 2000, Volume 2, Issue 7, Pages 74-78
Studies are presented on five radio propagation models in ITU - R recommendations. The mcxlels include statistical prediction method for tropospheric scatter transmission loss, prediction method for sea reflection fading in maritime mobile satellite telecommunications, conversion method for ionosphereic scintillation fading, simplified prediction method for attenuation by atmospheric gases and modified prediction method for field strength in land mobile services.
Keywords： radio propagation tropospheric scatter sea reflection ionospheric scintillation attenuation by atmospheric gases
Research on Prony’s method modeling in multi-target detection of stepped-frequency radar
Hu Tiling,Li Xingguo
Strategic Study of CAE 2008, Volume 10, Issue 10, Pages 67-71
Stepped-frequency signal is a broad band signal which enhances range resolution of radar at the cost of increasing bandwidth. Baseband signal that is received in stepped-frequency radar can be thought of as the linear combination of exponential function which contains target information, while Prony algorithm is a mathematical mode which uses a linear combination of exponential function to describe equal space between sampling data. Extended Prony algorithm is applied to stepped-frequency radar, which can obtain more exact target information and overcome the shortcomings of using IDFT to synthesize high resolution range profiles. Corresponding modeling analysis and experiment simulation explain the advantages of Prony's method.
Keywords： high resolution radar stepped-frequency signal extended Prony’s method multi-scattering center
Title Author Date Type Operation
The system design and application of HY-2A scatterometer
Wang Xiaoning,Liu Lixia,Chen Wenxin
Journal Article
An Ultrasonic Backscatter Instrument for Cancellous Bone Evaluation in Neonates
Chengcheng Liu,Rong Zhang,Ying Li,Feng Xu,Dean Ta,Weiqi Wang
Journal Article
HY-2A microwave scatterometer wind retrieval algorithm
Lin Mingsen,Zou Juhong,Xie Xuetong and Zhang Yi
Journal Article
cattering-absorbing method for the detection of 16.7 MeV high-energy pulsed gamma
Tan Xinjian,Ouyang Xiaoping,Wang Qunshu
Journal Article
Application of Wavelet Transform to Acoustic Radiation and Scattering
Wen Lihua,Ren Xingmin
Journal Article
Study of Scattering Characteristic of Fire Smoke Based on Mie Theory
Shu Xueming,Fang Jun,Shao Quan,Yuan Hongyong
Journal Article
Research on the preprocessing of HY-2A space-borne scatterometer data
Zhang Yi,Lin Minseng,Song Qingtao,Xie Xuetong and Zou Juhong
Journal Article
De-scattering and edge-enhancement algorithms for underwater image restoration
Pan-wang PAN, Fei YUAN, En CHENG
Journal Article
The study on oceanic vector wind field retrieve technique of the HY-2 satellite
Jiang Xingwei,Lin Mingsen
Journal Article
Validation of wind vectors retrieved by the HY-2A microwave scatterometer using NC EP model data
Mu Bo,Lin Mingsen,Peng Hailong,Song Qingtao,Zhou Wu
Journal Article
Performance analysis of the HaiYang-2A satellite microwave scatterometer measurements based on tropical rainforests
Peng Hailong,Mu Bo,Lin Mingsen,Zhou Wu
Journal Article
An application study of the HY-2 scatterometer on monitoring typhoon events in the northerwest Pacific
Lin Mingsen,Zhang Yi,Song Qingtao,Xie Xuetong,Zou Juhong
Journal Article
Numerical Simulation of the Interaction Between Smoke and Water Mist in Fire
Ye Dong,Jiang Yong
Journal Article
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