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Turbidity-adaptive underwater image enhancement method using image fusion

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-021-0669-8

摘要: Clear, correct imaging is a prerequisite for underwater operations. In real freshwater environment including rivers and lakes, the water bodies are usually turbid and dynamic, which brings extra troubles to quality of imaging due to color deviation and suspended particulate. Most of the existing underwater imaging methods focus on relatively clear underwater environment, it is uncertain that if those methods can work well in turbid and dynamic underwater environments. In this paper, we propose a turbidity-adaptive underwater image enhancement method. To deal with attenuation and scattering of varying degree, the turbidity is detected by the histogram of images. Based on the detection result, different image enhancement strategies are designed to deal with the problem of color deviation and blurring. The proposed method is verified by an underwater image dataset captured in real underwater environment. The result is evaluated by image metrics including structure similarity index measure, underwater color image quality evaluation metric, and speeded-up robust features. Test results exhibit that the method can correct the color deviation and improve the quality of underwater images.

关键词: turbidity     underwater image enhancement     image fusion     underwater robots     visibility    

基于去散射与边缘增强算法的水下图像复原 Research Papers

Pan-wang PAN, Fei YUAN, En CHENG

《信息与电子工程前沿(英文)》 2019年 第20卷 第6期   页码 862-871 doi: 10.1631/FITEE.1700744

摘要: 对色差严重和边缘模糊的水下图像需进行复原。一般分两步:去散射和边缘增强。首先,提出一种用于水下图像去散射的多尺度迭代框架。利用卷积神经网络估计传输图,再用自适应双边滤波器改进传输图估计结果。由于无可用数据集训练网络,收集包含2000个水下图像的数据集以获得合成数据。其次,采用白平衡算法消除水下图像的色偏。最后将图像转换到特殊变换域,使用非下采样轮廓波变换对边缘去噪和增强。结果表明:该方法主、客观质量均明显优于现有方法。

关键词: 图像散射;边缘增强;卷积神经网络;非下采样轮廓波变换    

Detecting large-scale underwater cracks based on remote operated vehicle and graph convolutional neural

Wenxuan CAO; Junjie LI

《结构与土木工程前沿(英文)》 2022年 第16卷 第11期   页码 1378-1396 doi: 10.1007/s11709-022-0855-8

摘要: It is of great significance to quickly detect underwater cracks as they can seriously threaten the safety of underwater structures. Research to date has mainly focused on the detection of above-water-level cracks and hasn’t considered the large scale cracks. In this paper, a large-scale underwater crack examination method is proposed based on image stitching and segmentation. In addition, a purpose of this paper is to design a new convolution method to segment underwater images. An improved As-Projective-As-Possible (APAP) algorithm was designed to extract and stitch keyframes from videos. The graph convolutional neural network (GCN) was used to segment the stitched image. The GCN’s m-IOU is 24.02% higher than Fully convolutional networks (FCN), proving that GCN has great potential of application in image segmentation and underwater image processing. The result shows that the improved APAP algorithm and GCN can adapt to complex underwater environments and perform well in different study areas.

关键词: underwater cracks     remote operated vehicle     image stitching     image segmentation     graph convolutional neural network    

基于学习自适应区域选择的自动增强图像 None

Na LI, Jian ZHAN

《信息与电子工程前沿(英文)》 2019年 第20卷 第2期   页码 206-221 doi: 10.1631/FITEE.1700125

摘要: 如今数码相机被广泛用于日常摄影。然而,部分照片缺乏细节,需要增强处理。很多现有图像增强算法基于局部区域,而且同一图像所选区域尺寸通常是固定的。用户需手工选择合适的区域尺寸获取最佳图像增强效果。提出一种基于自适应区域选择的自动增强图像算法。该算法采用明暗两个通道,解决各类图像曝光问题。对网上爬取的大量自然图像统计分析获取阈值,自动选择用于通道提取的区域尺寸。该方法可自动增强模糊或者曝光不足/背光的图像,无需任何用户交互。实验结果表明,该算法对现有基于区域的图像增强算法有显著改进。

关键词: 图像增强;对比度增强;暗通道;明通道;自适应区域处理    

Classical and state-of-the-art approaches for underwater image defogging: a comprehensive survey

Jing-chun Zhou, De-huan Zhang, Wei-shi Zhang,zhoujingchun@dlmu.edu.cn,zhangdehuan@dlmu.edu.cn,teesiv@dlmu.edu.cn

《信息与电子工程前沿(英文)》 2020年 第21卷 第12期   页码 1671-1814 doi: 10.1631/FITEE.2000190

摘要: In underwater scenes, the quality of the video and image acquired by the underwater imaging system suffers from severe degradation, influencing target detection and recognition. Thus, restoring real scenes from blurred videos and images is of great significance. Owing to the light absorption and scattering by suspended particles, the images acquired often have poor visibility, including color shift, low contrast, noise, and blurring issues. This paper aims to classify and compare some of the significant technologies in , presenting a comprehensive picture of the current research landscape for researchers. First we analyze the reasons for degradation of underwater images and the underwater optical imaging model. Then we classify the technologies into three categories, including image , image , and deep learning approaches. Afterward, we present the objective and analyze the state-of-the-art approaches. Finally, we summarize the shortcomings of the defogging approaches for underwater images and propose seven research directions.

基于质量感知的水下图像自适应压缩方法 Regular Papers

Ya-qiong CAI, Hai-xia ZOU, Fei YUAN

《信息与电子工程前沿(英文)》 2019年 第20卷 第5期   页码 716-730 doi: 10.1631/FITEE.1700737

摘要: 本文首先分别对压缩感知和嵌入式编码两种压缩策略下的水下压缩图像进行质量感知,然后利用图像活动性IAM(Image Activity Measurement)与BPP-SSIM(Bits Per Pixel

关键词: 水下图像压缩;SPIHT压缩;压缩感知;压缩质量预测    

水下交通隧道的设计与施工

王梦恕

《中国工程科学》 2009年 第11卷 第7期   页码 4-10

摘要:

综合论述了水下隧道在穿越江河湖海时所有的优势,介绍了水下交通隧道的设计与施工概况,讨论了水下隧道勘察设计、施工的几项关键技术,详细介绍了水下隧道施工的常用方法。

关键词: 水下隧道     设计     施工    

Centrifuge experiment and numerical analysis of an air-backed plate subjected to underwater shock loading

Zhijie HUANG, Xiaodan REN, Zuyu CHEN, Daosheng LING

《结构与土木工程前沿(英文)》 2019年 第13卷 第6期   页码 1350-1362 doi: 10.1007/s11709-019-0559-x

摘要: In this study, systematic centrifuge experiments and numerical studies are conducted to investigate the effect of shock loads due to an underwater explosion on the dynamic responses of an air-backed steel plate. Numerical simulations with three different models of pressure time history generated by underwater explosion were carried out. The first model of pressure time history was measured in test. The second model to predict the time history of shock wave pressure from an underwater explosion was created by Cole in 1948. Coefficients of Cole’s formulas are determined experimentally. The third model was developed by Zamyshlyaev and Yakovlev in 1973. All of them are implemented into the numerical model to calculate the shock responses of the plate. Simulated peak strains obtained from the three models are compared with the experimental results, yielding average relative differences of 21.39%, 45.73%, and 13.92%, respectively. The Russell error technique is used to quantitatively analyze the correlation between the numerical and experimental results. Quantitative analysis shows that the simulated strains for most measurement points on the steel plate are acceptable. By changing the scaled distances, different shock impulses were obtained and exerted on the steel plate. Systematic numerical studies are performed to investigate the effect of the accumulated shock impulse on the peak strains. The numerical and experimental results suggest that the peak strains are strongly dependent on the accumulated shock impulse.

关键词: underwater explosion     centrifuge experiment     shock load     dynamic response     accumulated shock impulse    

Effects of thermocline on performance of underwater glider’s power system propelled by ocean thermal

Hai YANG, Jie MA,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 472-479 doi: 10.1007/s11708-009-0052-7

摘要: The thermal glider’s changeable volume produces propelling force to power the glider’s descending and ascending through the thermocline. The different depth, thickness, and intensity of the thermocline at different seasons and locations affect the working processes of the glider’s power system. Based on the enthalpy method, a mathematical model of the underwater glider’s power system was established and the time efficiency of operation was introduced, so that the effects of different thermoclines on the underwater glider’s power system were analyzed theoretically. The simulation result shows that the thermocline affects the transition time of the phase change processes of working fluids within the thermal engine tubes. There exist the threshold values of the thermocline’s depth and upper thickness for the power system’s operation. A depth or upper thickness of the thermocline less than the corresponding threshold leads the power system to work abnormally. To keep the power system working efficiently, a glider must be kept in warm surface water for a certain period before it moves through cold water, so that the time efficiency of operation is reduced. A less time efficiency of operation is unfavorable to the thermal glider to penetrate through the ocean currents.

关键词: mathematical     underwater glider     system working     certain     corresponding threshold    

Gradient-based compressive image fusion

Yang CHEN,Zheng QIN

《信息与电子工程前沿(英文)》 2015年 第16卷 第3期   页码 227-237 doi: 10.1631/FITEE.1400217

摘要: We present a novel image fusion scheme based on gradient and scrambled block Hadamard ensemble (SBHE) sampling for compressive sensing imaging. First, source images are compressed by compressive sensing, to facilitate the transmission of the sensor. In the fusion phase, the image gradient is calculated to reflect the abundance of its contour information. By compositing the gradient of each image, gradient-based weights are obtained, with which compressive sensing coefficients are achieved. Finally, inverse transformation is applied to the coefficients derived from fusion, and the fused image is obtained. Information entropy (IE), Xydeas’s and Piella’s metrics are applied as non-reference objective metrics to evaluate the fusion quality in line with different fusion schemes. In addition, different image fusion application scenarios are applied to explore the scenario adaptability of the proposed scheme. Simulation results demonstrate that the gradient-based scheme has the best performance, in terms of both subjective judgment and objective metrics. Furthermore, the gradient-based fusion scheme proposed in this paper can be applied in different fusion scenarios.

关键词: Compressive sensing (CS)     Image fusion     Gradient-based image fusion     CS-based image fusion    

Edge detection of steel plates at high temperature using image measurement

Qiong Zhou, Qi An

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 77-82 doi: 10.1007/s11465-009-0013-1

摘要: An edge detection method for the measurement of steel plate’s thermal expansion is proposed in this paper, where the shrinkage of a steel plate is measured when temperature drops. First, images are picked up by an imaging system; a method of regional edge detection based on grayscales’ sudden change is then applied to detect the edges of the steel plate; finally, pixel coordinates of the edge position are transformed to physical coordinates through calibration parameters. The experiment shows that the real-time, high precision, and non-contact measurement of the steel plate’s edge position under high temperature can be realized using the imaging measurement method established in this paper.

关键词: thermal expansion     image measurement     edge detection     image calibration    

Aslotted floor acquisitionmultiple access based MACprotocol for underwater acoustic networks withRTS

Liang-fang QIAN,Sen-lin ZHANG,Mei-qin LIU

《信息与电子工程前沿(英文)》 2015年 第16卷 第3期   页码 217-226 doi: 10.1631/FITEE.1400187

摘要: Long propagation delay, limited bandwidth, and high bit error rate pose great challenges in media access control (MAC) protocol design for underwater acoustic networks. A MAC protocol called slotted floor acquisition multiple access (slotted-FAMA) suitable for underwater acoustic networks is proposed and analyzed. This FAMA based protocol adds a time slot mechanism to avoid DATA packet collisions. However, slotted-FAMA is not suitable for dense networks since the multiple request-to-send (RTS) attempts problem in dense networks is serious and greatly limits the network throughput. To overcome this drawback, this paper proposes a slotted-FAMA based MAC protocol for underwater acoustic networks, called RC-SFAMA. RC-SFAMA introduces an RTS competition mechanism to keep the network from high frequency of backoff caused by the multiple RTS attempts problem. Via the RTS competition mechanism, useful data transmission can be completed successfully when the situation of multiple RTS attempts occurs. Simulation results show that RC-SFAMA increases the network throughput efficiency as compared with slotted-FAMA, and minimizes the energy consumption.

关键词: Underwater acoustic networks     Medium access control (MAC)     Request-to-send (RTS) competition     Throughput     Energy consumption    

海洋水下立体观测技术装备发展研究

马蕊,赵修涛,柳存根

《中国工程科学》 2020年 第22卷 第6期   页码 19-25 doi: 10.15302/J-SSCAE-2020.06.003

摘要:

建立水下立体观测网来获得科学、实时、全面的数据,是未来认识、开发、利用海洋的重要方向。本文分析了发展海洋水下立体观测技术装备的需求和必要性,对比了国内外相关装备的发展现状,进一步剖析我国领域发展面临的问题,研判作为海洋水下观测关键环节的传感器技术进展点。研究认为,我国海洋观测平台技术有了很大进步,但在海洋关键传感器、高精度传感器方面依然落后于世界先进水平;海洋观测的大数据与实际需求之间有所脱节,海洋传感器缺乏改进平台支撑。研究提出了支持海洋关键传感器研究成果高效转化、统筹管理国家海洋水下立体观测技术装备、建立海上仪器装备国家公共试验平台等对策建议,以期为相关领域中长期发展提供方向参照。

关键词: 海洋观测     海底观测网     水下移动观测平台     水下传感器    

Performance enhancement of partially shaded solar PV array using novel shade dispersion technique

Namani RAKESH,T. Venkata MADHAVARAM

《能源前沿(英文)》 2016年 第10卷 第2期   页码 227-239 doi: 10.1007/s11708-016-0405-y

摘要: Solar photo voltaic array (SPVA) generates a smaller amount of power than the standard rating of the panel due to the partial shading effect. Since the modules of the arrays receive different solar irradiations, the P-V characteristics of photovoltaic (PV) arrays contain multiple peaks or local peaks. This paper presents an innovative method (magic square) in order to increase the generated power by configuring the modules of a shaded photovoltaic array. In this approach, the physical location of the modules in the total cross tied (TCT) connected in the solar PV array is rearranged based on the magic square arrangement pattern. This connection is done without altering any electrical configurations of the modules in the PV array. This method can distribute the shading effect over the entire PV array, without concentrating on any row of modules and can achieve global peaks. For different types of shading patterns, the output power of the solar PV array with the proposed magic square configuration is compared with the traditional configurations and the performance is calculated. This paper presents a new reconfiguration technique for solar PV arrays, which increases the PV power under different shading conditions. The proposed technique facilitates the distribution of the effect of shading over the entire array, thereby, reducing the mismatch losses caused by partial shading. The theoretical calculations are tested through simulations in Matlab/Simulink to validate the results. A comparison of power loss for different types of topologies under different types of shading patterns for a 4 × 4 array is also explained.

关键词: photovoltaic cells     mismatch loss     shading patterns     partial shading     magic square     power enhancement     global peaks and total cross tied (TCT)    

Revolutionizing heat transport enhancement with liquid metals: Proposal of a new industry of water-free

Haiyan LI, Jing LIU

《能源前沿(英文)》 2011年 第5卷 第1期   页码 20-42 doi: 10.1007/s11708-011-0139-9

摘要: Water is perhaps the most widely adopted working fluid in conventional industrial heat transport engineering. However, it may no longer be the best option today due to the increasing scarcity of water resources. Furthermore, the wide variations in water supply throughout the year and across different geographic regions also makes it harder to easily access. To address this issue, finding new alternatives to replace water-based technologies is imperative. In this paper, the concept of a water-free heat exchanger is proposed and comprehensively analyzed for the first time. The liquid metal with a low melting point is identified as an ideal fluid that can flexibly be used within a wide range of working temperatures. Some liquid metals and their alloys, which have previously received little attention in thermal management areas, are evaluated. With superior thermal conductivity, electromagnetic field drivability, and extremely low power consumption, liquid metal coolants promise many opportunities for revolutionizing modern heat transport processes: serving as heat transport fluid in industries, administrating thermal management in power and energy systems, and innovating enhanced cooling in electronic or optical devices. Furthermore, comparative analyses are conducted to understand the technical barriers encountered by advanced water-based heat transfer strategies and clarify this new frontier in heat-transport study. In addition, the unique merits of liquid metals that could lead to innovative heat exchanger technologies are evaluated comprehensively. A few promising industrial situations, such as heat recovery, chip cooling, thermoelectricity generation, and military applications, where liquid metals could play irreplaceable roles, were outlined. The technical challenges and scientific issues thus raised are summarized. With their evident ability to meet various critical requirements in modern advanced energy and power industries, liquid metal-enabled technologies are expected to usher a new and global era of water-free heat exchangers.

关键词: heat exchanger     liquid metal     water resource     heat transport enhancement     coolant     thermal management     process engineering     energy crisis     chip cooling    

标题 作者 时间 类型 操作

Turbidity-adaptive underwater image enhancement method using image fusion

期刊论文

基于去散射与边缘增强算法的水下图像复原

Pan-wang PAN, Fei YUAN, En CHENG

期刊论文

Detecting large-scale underwater cracks based on remote operated vehicle and graph convolutional neural

Wenxuan CAO; Junjie LI

期刊论文

基于学习自适应区域选择的自动增强图像

Na LI, Jian ZHAN

期刊论文

Classical and state-of-the-art approaches for underwater image defogging: a comprehensive survey

Jing-chun Zhou, De-huan Zhang, Wei-shi Zhang,zhoujingchun@dlmu.edu.cn,zhangdehuan@dlmu.edu.cn,teesiv@dlmu.edu.cn

期刊论文

基于质量感知的水下图像自适应压缩方法

Ya-qiong CAI, Hai-xia ZOU, Fei YUAN

期刊论文

水下交通隧道的设计与施工

王梦恕

期刊论文

Centrifuge experiment and numerical analysis of an air-backed plate subjected to underwater shock loading

Zhijie HUANG, Xiaodan REN, Zuyu CHEN, Daosheng LING

期刊论文

Effects of thermocline on performance of underwater glider’s power system propelled by ocean thermal

Hai YANG, Jie MA,

期刊论文

Gradient-based compressive image fusion

Yang CHEN,Zheng QIN

期刊论文

Edge detection of steel plates at high temperature using image measurement

Qiong Zhou, Qi An

期刊论文

Aslotted floor acquisitionmultiple access based MACprotocol for underwater acoustic networks withRTS

Liang-fang QIAN,Sen-lin ZHANG,Mei-qin LIU

期刊论文

海洋水下立体观测技术装备发展研究

马蕊,赵修涛,柳存根

期刊论文

Performance enhancement of partially shaded solar PV array using novel shade dispersion technique

Namani RAKESH,T. Venkata MADHAVARAM

期刊论文

Revolutionizing heat transport enhancement with liquid metals: Proposal of a new industry of water-free

Haiyan LI, Jing LIU

期刊论文