30 results on '"Zhang, Zhifeng"'
Search Results
2. Combined Deep Learning With Directed Acyclic Graph SVM for Local Adjustment of Age Estimation
- Author
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Cao Jie, Zhang Zhifeng, Cui Xiao, and Zheng Qian
- Subjects
General Computer Science ,Computer science ,business.industry ,Deep learning ,Feature extraction ,General Engineering ,deep learning ,Pattern recognition ,02 engineering and technology ,Directed acyclic graph ,local adjust ,Support vector machine ,Set (abstract data type) ,020204 information systems ,0202 electrical engineering, electronic engineering, information engineering ,Age estimation ,020201 artificial intelligence & image processing ,General Materials Science ,directed acyclic graph SVM ,Artificial intelligence ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,business ,Representation (mathematics) ,lcsh:TK1-9971 - Abstract
In order to further improve the accuracy of age estimation, a locally adjusted age estimation algorithm based on deep learning and directed acyclic graph SVM is proposed. In the training phase, SE-ResNet-50 network pre-trained by the VGGFace2 dataset is first fine-tuned. Once the network converges, and the vector consisting of the parameters of the last fully connected layer is used as a representation and train multiple One-Versus-One SVMs. In the test phase, we first sent the face image to be estimated into SE-ResNet-50 to obtain a rough age estimation value, then set the specific neighborhood, and finally combined the trained SVM into a directed acyclic graph SVM and set specific neighborhood with the global estimate as the center for accurate age estimate. In order to show the universality of the proposed coarse-to-fine or/and global-to-local method, experiments were carried out on MORPH and AFAD images of different races, and the results verified the effectiveness of the algorithm.
- Published
- 2021
3. Design and Implementation for the High Voltage DC-DC Converter of the Subsea Observation Network
- Author
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Kai Xie, Sa Xiao, Qingchao Xia, Gu Haolun, Feng Zhang, Yang Ning, Yong Wu, Jiawei Ni, and Zhang Zhifeng
- Subjects
Computer science ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 ,Ocean Engineering ,GC1-1581 ,02 engineering and technology ,Oceanography ,Fault (power engineering) ,electric energy conversion ,law.invention ,law ,0202 electrical engineering, electronic engineering, information engineering ,Transformer ,Water Science and Technology ,Civil and Structural Engineering ,Power transmission ,business.industry ,020208 electrical & electronic engineering ,Electrical engineering ,High voltage ,021001 nanoscience & nanotechnology ,modular multilevel resonant ,subsea observation network ,RLC circuit ,Voltage regulation ,0210 nano-technology ,business ,Subsea ,Voltage - Abstract
The subsea observation network has become an indispensable means of ocean exploration worldwide. However, the scale of the subsea observation network is limited by the power supply voltage and power level. Hence, to promote the development of a subsea observation network, this paper investigates the underwater high voltage DC-DC converter (HVC), which greatly improves the voltage and power level of the subsea observation network. The traditional series-parallel converter based on multi-module is faced with many technical problems, such as difficult transformer isolation, many fault points, low power density under higher input voltage level, and higher output power. The subsea HVC of this paper adopts a modular multilevel resonant DC-DC converter. The main circuit of HVC is designed in detail, including a module circuit, a resonant circuit, and a control scheme. Through the combination of the sub-module removal voltage regulation and closed-loop control, the converter can still output a stable voltage of 375 V when the input voltage changes. The modular sub-module and centralized transformer structure enables the converter to isolate high voltage easily, small volume, and high power density. The simulation and experiment results show the proposed HVC meets the design requirements and has good application prospects. It can be applied to submarine power transmission and distribution needs because of its wide range, large transformation ratio, and high efficiency.
- Published
- 2021
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4. Use of a coded voltage signal for cable switching and fault isolation in cabled seafloor observatories
- Author
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Yanhu Chen, Wang Jun, Zhang Zhifeng, De-jun Li, Bo Jin, and Canjun Yang
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Power transmission ,010505 oceanography ,Computer Networks and Communications ,Computer science ,business.industry ,Reliability (computer networking) ,Electrical engineering ,010502 geochemistry & geophysics ,01 natural sciences ,Signal ,Seafloor spreading ,Fault detection and isolation ,Hardware and Architecture ,Signal Processing ,Path (graph theory) ,Ocean exploration ,Electrical and Electronic Engineering ,business ,0105 earth and related environmental sciences ,Voltage - Abstract
Cabled seafloor observatories play an important role in ocean exploration for its long-term, real-time, and in-situ observation characteristics. In establishing a permanent, reliable, and robust seafloor observatory, a highly reliable cable switching and fault isolation method is essential. After reviewing the advantages and disadvantages of existing switching methods, we propose a novel active switching method for network configuration. Without additional communication path requirements, the switching method provides a way to communicate with a shore station through an existing power transmission path. A coded voltage signal with a distinct sequence is employed as the communication medium to transmit commands. The analysis of the maximum bit frequency of the voltage signals guarantees the accuracy of command recognition. A prototype based on the switching method is built and tested in a laboratory environment, which validated the functionality and reliability of the method.
- Published
- 2018
5. Deep Fuzzy Classification by Stacked Architecture for Epileptic Electroencephalograms Signals
- Author
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Chen Yifeng, Xuebao Li, Wang Sifan, Yanfang Zheng, Xu Chao, Zhou Ta, and Zhang Zhifeng
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Fuzzy classification ,Computer science ,business.industry ,Health Informatics ,Radiology, Nuclear Medicine and imaging ,Pattern recognition ,Artificial intelligence ,Architecture ,business - Published
- 2018
6. Computer Software Technology Under the Background of Big Data Development
- Author
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Zhang Zhifeng and Lv Ying
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Engineering management ,Data processing ,Engineering ,Landmark ,Quality of life (healthcare) ,business.industry ,Big data ,Computer software ,business ,Social production ,Economic benefits ,Computer technology - Abstract
With the continuous development of science and technology in our country, big data technology is becoming more and more mature. In recent years, the application of computer software in our country is more and more extensive. As an important part of social production, it is of great significance to strengthen the research of computer software technology. Computer technology, as one of the landmark technologies in the 21st century, has a direct relationship with social production and people’s quality of life. Therefore, this paper focuses on the application of computer software technology in the era of big data, to improve the data processing capacity and strengthen the economic benefits of social production. Therefore, it is of great significance to strengthen the application of computer software technology in the era of big data.
- Published
- 2020
7. Investigations on the Signal Recovery From the Non-Absorption Transmission Loss in Wavelength Modulation Spectroscopy
- Author
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Cun-Guang Zhu, Pengpeng Wang, Feng Peng, and Zhang Zhifeng
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Materials science ,business.industry ,Transmission loss ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Stability (probability) ,010309 optics ,Wavelength modulation spectroscopy ,Optics ,Signal-to-noise ratio (imaging) ,0103 physical sciences ,Automatic gain control ,Electrical and Electronic Engineering ,0210 nano-technology ,Absorption (electromagnetic radiation) ,Spectroscopy ,business ,Instrumentation ,Reliability (statistics) - Abstract
In practical applications, the signal-to-noise ratio (SNR), reliability, and the long-term stability of wavelength modulation spectroscopy (WMS) system is limited by the non-absorption transmission loss. In this investigation, we report on a signal recovery method to remove the impact of non-absorption transmission loss based on an automatic gain closed-loop control. The deviation of the WMS system with the introduced signal recovery method has been observed to be below 4.27% under the non-absorption transmission loss which varied from 0 dB to −6.02 dB, and is about 13 times lower than the ordinary system. The proposed method is suitable for promoting the reliability and stability of WMS system under rigorous circumstances. Besides, it has the potential value in the multi-point detection or to achieve a higher SNR.
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- 2018
8. Stacked Unitwise Fast Combination Classification for Single Hidden Layer Neural Networks Using Extreme Learning Machine on EEG Signals
- Author
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Chuxi Nan, Zhang Zhifeng, Yanfang Zheng, Wang Sifan, Hang Hongjuan, Xuebao Li, and Zhou Ta
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medicine.diagnostic_test ,Artificial neural network ,Computer science ,business.industry ,medicine ,Health Informatics ,Radiology, Nuclear Medicine and imaging ,Pattern recognition ,Hidden layer ,Artificial intelligence ,Electroencephalography ,business ,Extreme learning machine - Published
- 2018
9. Three-dimensional digitizing and anatomic study of lumbar vertebral canal and pedicle in children
- Author
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Zhang Zhifeng, Zhijun Li, Xiao-he Li, Shang Gao, Wang Chaoqun, Wang Xing, Zhang Yuanzhi, Shi Jun, and Shaojie Zhang
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Urology ,medicine.medical_treatment ,lumbar vertebra ,lcsh:Medicine ,Lumbar vertebrae ,03 medical and health sciences ,Fixation (surgical) ,0302 clinical medicine ,Lumbar ,children ,morphologic characteristics ,medicine ,Internal fixation ,Spinal canal ,3D reconstruction measurement ,Orthodontics ,Original Paper ,030222 orthopedics ,business.industry ,lcsh:R ,Gastroenterology ,Biomechanics ,Obstetrics and Gynecology ,Anatomic Variation ,pedicle ,medicine.anatomical_structure ,Surgery ,Spine injury ,business ,030217 neurology & neurosurgery - Abstract
Introduction Spinal pedicle screw internal fixation has been widely used in adult spine injury fixation. Due to being in a period of continuous growth and development, the spine of children at different ages shows different characteristics from adults in terms of anatomy, physiological function, and biomechanics. Furthermore, because the pedicle of children is small, has large anatomic variation, and has complex adjacent relationships, the surgical risk is extremely high. How to improve the screwing accuracy is the key to the success of children's pedicle internal fixation. Therefore, applying the concept of digitized and individualized screwing will be of great significance to children's pedicle screwing. Aim To investigate the morphologies, development patterns, and aging characteristics of the lumbar vertebral pedicle (LVP) in children aged 6-11 years, and to provide a theoretical basis for screw implantation and related biomechanical studies. Material and methods A total of 60 children aged 6-11 years were selected for the intergroup measurement and statistical analysis of their lumbar diameter, pedicle diameter, screw canal length (SCL), etc. Results Generally, the vertebral foramen diameter (ID), sagittal diameter (SD), pedicle width (PW), and SCL as well as the pedicle height (PH) exhibited an increasing trend with age and increasing vertebral sequence among children aged 6-11 years. Conclusions By observing the LVP in children using 3D digital reconstruction technology, the morphology of the spinal canal and pedicles at different lumbar segments showed obvious development patterns, and the best treatment protocol should be selected according to the LVP characteristics in clinical applications.
- Published
- 2018
10. High-precision displacement measurement method based on laser modulation
- Author
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Wang Xinjie, Liu Jiaming, Jiang Liujie, Zhai Yusheng, and Zhang Zhifeng
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Measurement method ,Laser modulation ,Optics ,Materials science ,business.industry ,Displacement (orthopedic surgery) ,business ,Atomic and Molecular Physics, and Optics - Published
- 2018
11. Investigation of Self-Driven Profiler with Buoyancy Adjusting System towards Ocean Thermal Energy
- Author
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Feng Zhang, Sheng Zhang, Bingzhe Chen, Gul Muhammad, Zhang Zhifeng, Canjun Yang, and Qingchao Xia
- Subjects
profiler ,Technology ,Ocean observations ,Buoyancy ,QH301-705.5 ,QC1-999 ,020209 energy ,02 engineering and technology ,self-driven ,engineering.material ,Marine energy ,0202 electrical engineering, electronic engineering, information engineering ,Ocean exploration ,General Materials Science ,Biology (General) ,Underwater ,QD1-999 ,Instrumentation ,Fluid Flow and Transfer Processes ,business.industry ,Physics ,Process Chemistry and Technology ,General Engineering ,Engineering (General). Civil engineering (General) ,021001 nanoscience & nanotechnology ,Computer Science Applications ,buoyancy adjusting system ,Chemistry ,Temperature gradient ,ocean thermal energy ,engineering ,Environmental science ,TA1-2040 ,0210 nano-technology ,business ,Energy (signal processing) ,Thermal energy ,Marine engineering - Abstract
An underwater profiler is one of the popular platforms for ocean observation. Due to energy limitations, conventional underwater vehicles have a short life span, which cannot meet the needs of long-term ocean exploration. Therefore, there is a growing interest in using ocean energy such as ocean thermal energy and wave energy for driving. This study aimed to investigate an energy-saving and ocean thermal energy (OTE)-powered buoyancy driving system of the ocean profiler. The purpose of this study was to explore an ocean profiler buoyancy driving system powered by ocean thermal energy (OTE). According to the seawater profile temperature gradient, an OTE-powered electro-hydraulic control system was designed, and the dynamic characteristics of this system are simulated and analyzed by using the power bonding diagram method. Based on the results conducted from lake tests, this profiler possesses the self-driving capability for using OTE perfectly. This research can provide important guidance for the design of the buoyancy drive system of underwater vehicles.
- Published
- 2021
12. An Active Node Switching Method Based on Discrete-Voltage Intervention for Seafloor Observation Network
- Author
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Canjun Yan, Yanhu Chen, Bo Jin, Xu Feifei, Zhang Zhifeng, and Dejun Li
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Engineering ,010505 oceanography ,business.industry ,Node (networking) ,010401 analytical chemistry ,Ocean Engineering ,Oceanography ,01 natural sciences ,Seafloor spreading ,0104 chemical sciences ,Intervention (counseling) ,business ,0105 earth and related environmental sciences ,Voltage ,Computer network - Abstract
The cabled seafloor observation network, which provides abundant power and broad bandwidth to seafloor scientific packages, has become one of the most efficient ocean exploration methods because of its long-term, real-time, and sustained presence. However, node failure or maintenance may shut down the system until the situation is cleared. An active node switching method based on discrete-voltage intervention is proposed to establish a reliable and robust underwater electrical network that allows the system to operate partially amid node failure or maintenance. This method switches a specific node on/off from the network whenever necessary. The main structure and operating mechanism of this switching method are presented in this paper. A prototype was established, and several tests were performed in a laboratory to validate its feasibility and reliability. The prototype was then integrated into a pool-testing underwater network that included a 50-km electrical/optical submarine cable between the base station and the junction box. The test results demonstrated that the active node-switching method can efficiently and reliably fix node failure emergency situations for cabled ocean networks.
- Published
- 2017
13. Pediatric Lumbar Pedicle Screw Placement Using Navigation Templates: A Cadaveric Study
- Author
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Zhang Zhifeng, Xing Wang, Zhijun Li, Shojie Zhang, Shi Jun, and Xiaohe Li
- Subjects
musculoskeletal diseases ,medicine.medical_specialty ,mesh: cadaver ,Computed tomography ,spine ,mesh: pediatric surgery ,Screw placement ,03 medical and health sciences ,0302 clinical medicine ,Lumbar ,lcsh:Orthopedic surgery ,Cadaver ,mesh: computer assisted ,pediatric surgery ,medicine ,navigation template ,Orthopedics and Sports Medicine ,mesh: spine ,Pedicle screw ,Children ,Orthodontics ,030222 orthopedics ,medicine.diagnostic_test ,business.industry ,lumbar spine ,equipment and supplies ,musculoskeletal system ,computer assisted ,Surgery ,cadaver ,lcsh:RD701-811 ,mesh: Bone screw ,surgical procedures, operative ,Orthopedic surgery ,Lumbar spine ,Original Article ,cadaver MeSH terms: Bone screw ,Cadaveric spasm ,business ,030217 neurology & neurosurgery - Abstract
Background: Pedicle screw technique is commonly used treatment of adult spinal trauma, tumor, degeneration. The application of pedicle screws is very challenging in children because children have a fast growing spine and spinal pedicle morphology of children and adult has large difference. 3 D reconstruction individual navigation templates improve the success rate of pediatric pedicle screw system. This study is aimed to provide a precise method for lumbar spine pedicle screw placement in children using computer-aided design and rapid prototyping technology. Materials and Methods: Computed tomography (CT) scans of cadaver specimens of 4 children were obtained, and the raw data were reconstructed using three-dimensional reconstruction software. Pedicle screws were placed using the conventional method or by using individually designed navigation templates based on the principles of reverse engineering and rapid prototyping technology. Results: We evaluated the accuracy of the pedicle screws placed using the two methods by CT scan. Ten navigation templates were designed for placement of 20 lumbar pedicle screws in the navigation group, and CT scan confirmed that all the screws were placed accurately in the corresponding pedicle. Conversely, of the 20 lumbar pedicle screws placed using the conventional method, 3 screws perforated the pedicle. The findings showed that lumbar pedicle screw placement was successful using navigation templates in children. Conclusions: This technique is simple, easy to master, and allows personalized screw placement, thus providing a new and feasible method for lumbar pedicle screw placement in children.
- Published
- 2017
14. An ultra-low frequency pendulum isolator using a negative stiffness magnetic spring
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Zhang Zhifeng, Yisheng Zheng, Xinong Zhang, Chicheng Ma, and Shuai Zhang
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010302 applied physics ,Physics ,business.industry ,Mechanical Engineering ,Negative stiffness ,Isolator ,Pendulum ,Structural engineering ,Condensed Matter Physics ,01 natural sciences ,Magnetic spring ,Electronic, Optical and Magnetic Materials ,010309 optics ,Mechanics of Materials ,0103 physical sciences ,Electrical and Electronic Engineering ,business ,Ultra low frequency - Published
- 2016
15. A high-precision roll angle measurement method
- Author
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Zhang Zhifeng, Feng Qibo, Su Yuling, Zhai Yusheng, and Wang Xinjie
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Physics ,Measurement method ,business.industry ,Detector ,Pentagonal prism ,Common-mode interference ,Photoelectric effect ,Polarization (waves) ,Atomic and Molecular Physics, and Optics ,Collimated light ,Electronic, Optical and Magnetic Materials ,Optics ,Prism ,Electrical and Electronic Engineering ,business - Abstract
A novel high-precision measurement method for measuring roll is presented. The pentagonal prism and corner-cube prism are used as splitting element and sensitive element, respectively. A pair of parallel collimated beams generated by a pair of splitting pentagonal prisms is incident upon the target moving along linear guide. Two beams returning from two corner-cube prisms on the target reach two four-quadrant photoelectric detectors (QD 1 and QD 2 ), respectively. So the roll can be measured by differential measurement based on QD 1 and QD 2 . Further, the measurement resolution can be doubled and resistance to common mode interference can be enhanced, by adopting common-path structure based on the polarization splitting prisms. Feasibility of the method is verified by theoretical analysis and experiments. When the system parameters apply to the values supposed, for the roll, the angular resolution can reach to 0.1″, and measuring accuracy is about 1″.
- Published
- 2015
16. Video Frame Interpolation Using Recurrent Convolutional Layers
- Author
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Li Chen, Li Song, Rang Xie, and Zhang Zhifeng
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Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,02 engineering and technology ,010501 environmental sciences ,Standard methods ,Volume sampling ,computer.software_genre ,01 natural sciences ,Optical imaging ,Kernel (image processing) ,Voxel ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Artificial intelligence ,Motion interpolation ,business ,computer ,0105 earth and related environmental sciences - Abstract
Frame interpolation attempts to generate intermediate frames given existing ones, which is challenging because of complex video scenes and motion. Standard methods first estimate motion between two continuous frames and then synthesize new ones. In this paper, we propose a novel frame interpolation method based on a video synthesis approach deep voxel flow (DVF). In DVF, a deep convolutional encoder-decoder predicts 3D voxel flow, and then a volume sampling layer synthesizes the intermediate frame guided by the flow. To improve the accuracy of voxel flow, we employ recurrent convolutional layers (RCL) in the encoder-decoder module to refine the flow step by step, called DVF-RCL. We also incorporate perceptual loss to increase the visual quality. Experiments demonstrate that our method greatly improves the performance of original DVF and produce results that compare favorably to state-of-the-art methods both quantitatively and qualitatively.
- Published
- 2018
17. Study on train wheel tread detects detection and classification
- Author
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Zhai Yusheng, Zhang Zhifeng, Tang Yiming, Yu Rong Li, Yuling Su, Geng Lijie, Wang Xinjie, and Yong-You Han
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010309 optics ,Computer science ,business.industry ,0103 physical sciences ,Computer vision ,02 engineering and technology ,Artificial intelligence ,Tread ,021001 nanoscience & nanotechnology ,0210 nano-technology ,business ,01 natural sciences - Published
- 2017
18. Research and Implementation of an IEEE 1588 PTP-Based Time Synchronization System for Chinese Experimental Ocean Observatory Network
- Author
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Bo Jin, Wang Jun, Canjun Yang, Yanhu Chen, Zhang Zhifeng, and Dejun Li
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Observatory ,Computer science ,business.industry ,Real-time computing ,Ocean Engineering ,Oceanography ,Telecommunications ,business ,Time synchronization - Abstract
With time synchronization becoming an important feature of cabled ocean observatory networks, an innovative approach using the IEEE 1588 standard featuring the precision timing protocol (PTP) is proposed. Both boundary clock (BC) and transparent clock (TC) based on PTP are analyzed, and the framework of a synchronization system mainly consisting of a shore station section, a junction box layer, and a science instrument layer is presented. The proposed time synchronization system was applied and tested on a laboratory setup of the Experimental Underwater Observatory Network System of China. Results indicate that the time accuracy of the proposed system satisfies the needs of the observatory networks either in BC mode or TC mode, and the time accuracy is better in TC mode, especially when the network structure becomes more complex.
- Published
- 2015
19. Key technologies of junction boxes for Chinese experimental ocean observatory networks
- Author
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Bo Jin, Yanhu Chen, Zhang Zhifeng, Canjun Yang, Dejun Li, and Wang Jun
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Engineering ,South china ,Observatory ,business.industry ,Sea trial ,Frame (networking) ,Synchronization (computer science) ,Key (cryptography) ,Junction box ,Seafloor observatory ,Telecommunications ,business - Abstract
Ocean observatory networks have been investigated and developed and are receiving considerable attention in the 21st century. As intermediate processing nodes, junction boxes (JBs) are essential sections of ocean observatory networks. This paper explored the key technologies of JBs for Chinese experimental seafloor observatory networks, including industrial control, Ethernet communication, and time synchronization technologies. Specific functional verifications of each section were conducted in the laboratory prior to sea trials. The JBs were packaged in a frame and were deployed in the East and South China Sea. Results of the laboratory and sea trial experiments demonstrated that the examined technologies were effective and could provide valid guarantee to the long operation of the JBs.
- Published
- 2015
20. A Novel Method to Assess Cotton Fiber Fineness and Maturity Based on Optoelectronic Measurement
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杨坤 Yang Kun, 任宇芬 Ren Yu-fen, 蒋逢春 Jiang Fengchun, and 张志峰 Zhang Zhifeng
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Microscope ,Materials science ,business.industry ,Maturity (sedimentology) ,Fineness ,Fraunhofer diffraction ,Atomic and Molecular Physics, and Optics ,law.invention ,symbols.namesake ,Optics ,law ,symbols ,Optoelectronics ,Fiber ,business - Abstract
The cotton′s maturity and fineness are the key parameters to evaluate the cotton fibers quality.The indirect parameters measurement can not accurately evaluate the cotton fiber′s quality.A direct method based on the optoelectronic measurement of Fraunhofer diffraction was presented.The measurement results were compared between the microscope and the optoelectronic setup.The results show that two methods have the good correlation(R=0.956,and SD=0.332).The optoelectronic technique can assess the cotton fiber′s maturity in the lab.
- Published
- 2011
21. A Novel Method for Dynamically Measuring Diameters of Train Wheels Using Laser Displacement Transducers
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张志峰 Zhang Zhifeng, 陈士谦 Chen Shiqian, 冯其波 Feng Qibo, 崔建英 Cui Jianying, and 高岩 Gao Yan
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Materials science ,Optics ,Transducer ,law ,business.industry ,Displacement (orthopedic surgery) ,Electrical and Electronic Engineering ,Laser ,business ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention - Published
- 2008
22. Research on influence on luminance of machine vision to measure cotton defects
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Qiao Lin, Wang Xinjie, Su Yuling, Zhai Yusheng, Zhang Zhifeng, Guo Ying-Ying, and Tang Yi-Ming
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Measure (data warehouse) ,business.industry ,Computer science ,Machine vision ,media_common.quotation_subject ,Image processing ,Luminance ,Field (computer science) ,Automotive engineering ,Light intensity ,Computer vision ,Quality (business) ,Artificial intelligence ,business ,Image resolution ,media_common - Abstract
Ginning cotton qualities influence seriously the quality of textiles. Ginning cotton is always mixed with various defects during the picking, transporting, storing, and processing. This paper proposed one novel method to solve the problems of intensity changes of light source. Firstly, the properties of cotton and defects are studied. Secondly, the setup of measuring system is introduced and image processing algorithm is proposed. Finally, experimental results are discussed and the optimal drive circuit of light sources is designed. The results show the measuring system can meet with the requirement of nondestructive measurement of ginning cotton quality. The experimental results show that the accuracy of the cotton defect's measuring system is above 90%, and the measuring time is within 3 second. This system can meet with the requirement of fast measurement of cotton ginning qualities in field.
- Published
- 2015
23. Experimental study of laser beam drift
- Author
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Lv Dongdong, Wang Xinjie, Li Yang, Chen Yinhang, Liu Wenlong, Su Yuling, Zhang Zhifeng, Li Jintao, and Zhai Yusheng
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Physics ,Beam diameter ,Distributed feedback laser ,business.industry ,Beam parameter product ,Laser linewidth ,Optics ,Physics::Accelerator Physics ,M squared ,Physics::Atomic Physics ,Laser power scaling ,Laser beam quality ,business ,Laser Doppler vibrometer - Abstract
Laser collimation technology is widely applied in the positioning and measurement. Because the accuracy is affected by the laser beam drift, so laser beam drift compensation is necessary. The complexity of sources and forms of laser beam drifts affect the compensation effect. The noise signals caused by electronic noise, laser source, and environment, are analyzed in detail. Further, the parallel drift and angular drift of various types of beam drift signals are estimated and the effectiveness of low-pass filter and mean process are verified and compared. This study is beneficial to analyzing various types of noise signals and building a more effective compensation models for laser beam drift.
- Published
- 2015
24. The Segmentation Interventricular Septum from MR Images
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Zhentai Lu, Wufan Chen, Qianjin Feng, Huan Ma, Zhang Zhifeng, Shengli Song, Deng Lujuan, Minghui Zhang, and Qian Zheng
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Anatomical location ,Computer science ,business.industry ,Initialization ,Pattern recognition ,Hough transform ,law.invention ,Euclidean distance ,symbols.namesake ,medicine.anatomical_structure ,law ,medicine ,Gaussian function ,symbols ,Entropy (information theory) ,Segmentation ,Artificial intelligence ,Interventricular septum ,business - Abstract
We present a fully automated method to segment the interventricular septum from cardiac MR images in this paper. By introducing the circular Hough transformation our model can automatically detect the contours of left ventricle as circles used as the initialization. The interior and exterior energies are weighted by the entropy, which improves the robust of the evolving curve. Local neighborhood information is used to evolve the level set function, which can reduce the impact of the heterogeneous grays inside of regions and improve the segmentation accuracy. The adaptive window size is utilized to reduce the sensitivity to initialization rather than a fixed window size. The Gaussian kernel is used to not only ensure the smoothness and stability of the level set function, but also eliminate the traditional Euclidean length term and re-initialization. Finally, we segment the septum automatically by the classical segmentation methods combined with anatomical location information. Extensive experiments indicate that the superior performance of the proposed method over the state-of-the-art methods in terms of both good robustness and high efficiency.
- Published
- 2015
25. Polymer Optical Fiber Bragg Grating
- Author
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Zhang Zhifeng
- Subjects
PHOSFOS ,Materials science ,Holographic grating ,Fiber Bragg grating ,business.industry ,Fiber optic sensor ,Optoelectronics ,Polarization-maintaining optical fiber ,Long-period fiber grating ,Plastic optical fiber ,business ,Photonic-crystal fiber - Published
- 2015
26. Denoising of Fraunhofer Diffraction Signal Based on Wavelet Analysis
- Author
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Xiaodong Zhang, Zhang Zhifeng, Chao Lu, Yuling Su, and Yunqi Hao
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Diffraction ,Materials science ,Noise measurement ,business.industry ,Noise (signal processing) ,Noise reduction ,Fast Fourier transform ,Wavelet transform ,Fraunhofer diffraction ,symbols.namesake ,Optics ,Wavelet ,biological sciences ,symbols ,bacteria ,business - Abstract
The diffraction methods were used to measure thin wires or fibers with some advantages. The method was based on Fraunhofer diffraction principle. The diffraction pattern can be detected by the Charge Coupled Device (CCD). CCD often produced the noise in the diffraction pattern and gave rise to the measuring error for the ambient disturbance. After theoretical simulation and analysis, the wavelet analysis was prior to the FFT method. The five repetition measurements of the diffraction pattern signals of the normal fiber were obtained. The five repetition measuring results showed that the wavelet analysis method was better than the FFT method to remove the noise from the signal. The diameter of the cotton fibers can assess the cotton’s qualities, so this research was very advantageous to the next study about the diameter measurement of the cotton fiber.
- Published
- 2010
27. A Novel Method on Wheelsets Geometric Parameters on Line Based on Image Processing
- Author
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Zhan Gao, Shuangyun Shao, and Zhang Zhifeng
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Vehicle dynamics ,Acceleration ,Engineering ,business.industry ,System of measurement ,Line (geometry) ,Calibration ,Mechanical engineering ,Railway engineering ,Image processing ,Structural engineering ,Flange ,business - Abstract
The flange thickness and rim inside thickness of the wheelset are key parameters that influence the wheel-rail contact. With the speed continuous increase of the rail vehicles, the wear of wheelset is becoming more and more serious, thus accelerating the changes of wheelset’s flanges, which will certainly bring security hidden troubles to the operation of railway, so it is very important to realize dynamic measurements of the wheelset’s flange thickness and rim inside thickness. This paper proposes a novel real-time measurement method to wheelsets based on the image processing. This system based on the triangular principle uses CCD (Charge-coupled device) to obtain the information of the wheelsets. In this system, the flange thickness can be uncontacted measured in real time. The standard deviation of the rim inside thickness is 0.47mm and that of the flange thickness is 0.635mm, and the error range is ±0.8mm, and ±1.0mm, respectively. When the train passes through the measurement system at the speed of 5km/h, the measurement results show that the measurement system can meet the measuring requirement on line.
- Published
- 2010
28. Research on Method to Measure Cotton Defects Based on Optoelectronic Technique
- Author
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王新杰 Wang Xinjie, 郭莹莹 Guo Yingying, 张志峰 Zhang Zhifeng, 杜银霄 Du Yinxiao, and 翟玉生 Zhai Yusheng
- Subjects
Computer science ,business.industry ,Measure (physics) ,Optoelectronics ,Nanotechnology ,Electrical and Electronic Engineering ,business ,Atomic and Molecular Physics, and Optics - Published
- 2015
29. Improving performance of superconducting fault current limiter with mutual-inductor
- Author
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Liangzhen Lin, Ying Ye, Zhang Zhifeng, and Xiao Liye
- Subjects
Superconductivity ,Electric power system ,Three phase power system ,Materials science ,Power system simulation ,business.industry ,Electrical engineering ,Superconducting fault current limiters ,Limiting ,business ,Inductor ,Current limiting reactor - Abstract
The novel method to improve the limiting capability of DC reactor type superconducting fault current limiter (SFCL) by using mutual inductor is presented in this paper. The configurations of the SFCL are described in detail, in which both a superconducting and a mutual inductor play roles of the limiting elements. The working principle of the SFCL is analyzed theoretically and the mathematical model of the SFCL is built. Simulation has been carried out by using EMTDC in a 10 kV/1 kA three-phase power system. The simulation show good results. The performance of the SFCL with mutual inductor is validated, and the feasibility of the SFCL with mutual inductor is also demonstrated
- Published
- 2005
30. Study on Influence of Dead Zone on Detection Range and Sensitivity Four-Quadrant Detector
- Author
-
王新杰 Wang Xinjie, 张志峰 Zhang Zhifeng, 白煌煌 Bai Huanghuang, 杨红军 Yang Hongjun, 杨桂栓 Yang Guishuan, 翟玉生 Zhai Yusheng, 郭莹莹 Guo Yingying, and 王才东 Wang Caidong
- Subjects
Optics ,business.industry ,Detector ,Dead zone ,Quadrant (instrument) ,Electrical and Electronic Engineering ,business ,Atomic and Molecular Physics, and Optics ,Geology - Published
- 2013
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