Search scope:
排序： Display mode:
Grazing incidence polarized light imaging of footwear prints Regular Article
Xin-yi Bi, Rui-fang Han, Ran Liao, Wu-sheng Feng, Da Li, Xue-jie Zhang, Hui Ma,liao.ran@sz.tsinghua.edu.cn
Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 11, Pages 1543-1550 doi: 10.1631/FITEE.1800383
Keywords： 偏振；图像增强；散射；粒子
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
Automatic image enhancement by learning adaptive patch selection None
Na LI, Jian ZHAN
Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 2, Pages 206-221 doi: 10.1631/FITEE.1700125
Today, digital cameras are widely used in taking photos. However, some photos lack detail and need enhancement. Many existing image enhancement algorithms are patch based and the patch size is always fixed throughout the image. Users must tune the patch size to obtain the appropriate enhancement. In this study, we propose an automatic image enhancement method based on adaptive patch selection using both dark and bright channels. The double channels enhance images with various exposure problems. The patch size used for channel extraction is selected automatically by thresholding a contrast feature, which is learned systematically from a set of natural images crawled from the web. Our proposed method can automatically enhance foggy or under-exposed/backlit images without any user interaction. Experimental results demonstrate that our method can provide a significant improvement in existing patch-based image enhancement algorithms.
Keywords： Image enhancement Contrast enhancement Dark channel Bright channel Adaptive patch based processing
Enhanced collection of scattered photons in nonlinear fluorescence microscopy by extended epi-detection with a silicon photomultiplier array Research Articles
Ruheng Shi, Cheng Jin, Chi Liu, Lingjie Kong,konglj@tsinghua.edu.cn
Frontiers of Information Technology & Electronic Engineering 2021, Volume 22, Issue 10, Pages 1289-1298 doi: 10.1631/FITEE.2000410
Keywords： 扩展背向探测；增强探测；非线性荧光显微镜；硅光电倍增管阵列
Engineered Functional Surfaces by Laser Microprocessing for Biomedical Applications Article
Guoqing Hu, Kai Guan, Libin Lu, Jiaru Zhang, Nie Lu, Yingchun Guan
Engineering 2018, Volume 4, Issue 6, Pages 822-830 doi: 10.1016/j.eng.2018.09.009
Metallic biomaterials are increasingly being used in various medical applications due to their high strength, fracture resistance, good electrical conductivity, and biocompatibility. However, their practical applications have been largely limited due to poor surface performance. Laser microprocessing is an advanced method of enhancing the surface-related properties of biomaterials. This work demonstrates the capability of laser microprocessing for biomedical metallic materials including magnesium and titanium alloys, with potential applications in cell adhesion and liquid biopsy. We investigate laser-material interaction, microstructural evolution, and surface performance, and analyze cell behavior and the surface-enhanced Raman scattering (SERS) effect. Furthermore, we explore a theoretical study on the laser microprocessing of metallic alloys that shows interesting results with potential applications. The results show that cells exhibit good adhesion behavior at the surface of the laser-treated surface, with a preferential direction based on the textured structure. A significant SERS enhancement of 6×103 can be obtained at the laser-textured surface during Raman measurement.
Keywords： Laser microprocessing Functional surface Metallic alloy Niocompatibility SERS
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
Survey on Particle Swarm Optimization Algorithm
Yang Wei,Li Chiqiang
Strategic Study of CAE 2004, Volume 6, Issue 5, Pages 87-94
Particle swarm optimization (PSO) is a new optimization technique originating from artificial life and evolutionary computation. The algorithm completes the optimization through following the personal best solution of each particle and the global best value of the whole swarm. PSO can be implemented with ease and few parameters need to be tuned. It has been successfully applied in many areas. In this paper, the basic principles of PSO are introduced at length, and various improvements and applications of PSO are also presented. Finally, some future research directions about PSO are proposed.
Keywords： swarm intelligence evolutionary algorithm particle swarm optimization
Image Engineering and Its Research Status in China
Zhang Yujin
Strategic Study of CAE 2000, Volume 2, Issue 8, Pages 91-94
This paper provides a well-regulated explanation of the definition as well as contents of image engineering, a classification of the theories of image engineering and the applications of image technology. In addition, a comprehensive survey on important Chinese publications about image engineering in the past five years is carried out. An analysis and a discussion of the statistics made on the classification results are also presented. This work shows a general and up-to-date picture of the current status, progress trends and application areas of image engineering in China. It also supplies useful information for readers doing research and/or application works in this field, and provides a helpful reference for editors of journals and potential authors of papers.
Keywords： image engineering publication survey
Impact of Polarization Mode Dispersion on High-Speed Optical Codes
Rao Min,Sun Xiaohan,Zhang Mingde
Strategic Study of CAE 2002, Volume 4, Issue 11, Pages 67-70
The first and second-order polarization mode dispersion (PMD) effect on the performance of 10 Gbit/s and 40 Gbit/s systems is studied. The statistical behavior of PMD is considered by simulating the nonreturn-to-zero (NRZ) and return-to-zero (RZ) pulses distortion and the system's Q-factor based on principal states of polarization (PSP) theory. It is found that the effect of PMD is significant in higher bit rate systems and the second-order PMD cannot be neglected. Furthermore, the RZ format is more tolerant to PMD than is the NRZ format, and the system performance is improved if the input pulses are appropriately chirped.
Keywords： polarization mode dispersion (PMD) non-return-to-zero (NRZ) return-to-zero (RZ) frequency chirp
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
Ali Darvish FALEHI,Ali MOSALLANEJAD
Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 3, Pages 394-409 doi: 10.1631/FITEE.1500317
Suppression of the dynamic oscillations of tie-line power exchanges and frequency in the affected interconnected power systems due to loading-condition changes has been assigned as a prominent duty of automatic generation control (AGC). To alleviate the system oscillation resulting from such load changes, implementation of flexible AC transmission systems (FACTSs) can be considered as one of the practical and effective solutions. In this paper, a thyristor-controlled series compensator (TCSC), which is one series type of the FACTS family, is used to augment the overall dynamic performance of a multi-area multi-source interconnected power system. To this end, we have used a hierarchical adaptive neuro-fuzzy inference system controller-TCSC (HANFISC-TCSC) to abate the two important issues in multi-area interconnected power systems, i.e., low-frequency oscillations and tie-line power exchange deviations. For this purpose, a multi-objective optimization technique is inevitable. Multi-objective particle swarm optimization (MOPSO) has been chosen for this optimization problem, owing to its high performance in untangling non-linear objectives. The efficiency of the suggested HANFISC-TCSC has been precisely evaluated and compared with that of the conventional MOPSO-TCSC in two different multi-area interconnected power systems, i.e., two-area hydro-thermal-diesel and three-area hydro-thermal power systems. The simulation results obtained from both power systems have transparently certified the high performance of HANFISC-TCSC compared to the conventional MOPSO-TCSC.
Keywords： Hierarchical adaptive neuro-fuzzy inference system controller (HANFISC) Thyristor-controlled series compensator (TCSC) Automatic generation control (AGC) Multi-objective particle swarm optimization (MOPSO) Power system dynamic stability Interconnected multi-source power systems
Application prospect of PSO in hydrology
Dong Qianjin,Cao Guangjing,Wang Xianjia,Dai Huichao,Zhao Yunfa
Strategic Study of CAE 2010, Volume 12, Issue 1, Pages 81-85
The basic algorithm and its flow are introduced at first, then its application to scheduling operation of reservoir, economic operation of hydropower and parameter calibration in hydrology field is discussed, the suggestion for future study is pointed out that should strengthen the study of adaptive mechanism and convergence performance in PSO, compare and combine with other technology, broaden the region of application to hydrology which may supply a new method for solving much optimal problem in hydrology field.
Keywords： hydrology science particle swarm optimization scheduling operation economical operation
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
Title Author Date Type Operation
Grazing incidence polarized light imaging of footwear prints
Xin-yi Bi, Rui-fang Han, Ran Liao, Wu-sheng Feng, Da Li, Xue-jie Zhang, Hui Ma,liao.ran@sz.tsinghua.edu.cn
Journal Article
De-scattering and edge-enhancement algorithms for underwater image restoration
Pan-wang PAN, Fei YUAN, En CHENG
Journal Article
Enhanced collection of scattered photons in nonlinear fluorescence microscopy by extended epi-detection with a silicon photomultiplier array
Ruheng Shi, Cheng Jin, Chi Liu, Lingjie Kong,konglj@tsinghua.edu.cn
Journal Article
Engineered Functional Surfaces by Laser Microprocessing for Biomedical Applications
Guoqing Hu, Kai Guan, Libin Lu, Jiaru Zhang, Nie Lu, Yingchun Guan
Journal Article
The system design and application of HY-2A scatterometer
Wang Xiaoning,Liu Lixia,Chen Wenxin
Journal Article
Impact of Polarization Mode Dispersion on High-Speed Optical Codes
Rao Min,Sun Xiaohan,Zhang Mingde
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
RETRACTED ARTICLE: Dynamic stability enhancement of interconnected multi-source power systems using hierarchical ANFIS controller-TCSC based on multi-objective PSO
Ali Darvish FALEHI,Ali MOSALLANEJAD
Journal Article
Application prospect of PSO in hydrology
Dong Qianjin,Cao Guangjing,Wang Xianjia,Dai Huichao,Zhao Yunfa
Journal Article
京公网安备 11010502051620号
