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一种基于边缘信息的车辆检测和跟踪方法 总被引：1，自引：0，他引：1
针对智能交通系统中运动车辆的检测和跟踪问题,提出1种基于边缘信息车辆检测和跟踪方法。利用背景边缘提取模板提取当前帧的精确背景边缘,进而获得前景车辆边缘,用形态学方法对其进行修复,寻找车辆的外轮廓,确定跟踪区域;由于车辆运动的特殊性,以当前帧的车速作为下一帧车速的预测值,并结合跟踪区域的外形信息进行匹配。从实验效果来看,该算法简单有效,适合于实时的车辆检测和跟踪系统。 相似文献
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An Odyssey IIb autonomous underwater vehicle (AUV) made by Bluefin Robotics, Inc., was acquired by the Marine Physical Laboratory, Scripps Institution of Oceanography, to conduct research in underwater acoustics as well as provide a platform for other scientific studies. The original Odyssey IIb tail cone was replaced with a ducted fan, vectored thrust system installed on vehicles currently sold by Bluefin. In initial sea tests with the new thrust system, the acoustic self noise levels of the vehicle while underway were 20 to 50 dB higher than typical ocean background noise levels, preventing the vehicle's use as a receiver of low level sounds. Controlled tests were performed to characterize the radiated and vibration noise of the AUV propulsion and actuators. Once this baseline was established, changes were made, mostly to the tail cone propulsion, to decrease the vehicle's self noise. The resulting self noise levels of the AUV from 10 Hz up to 10 kHz measured while underway by a hydrophone mounted on the AUV's inner shroud now are at or below typical shallow water background noise levels except in three bands; below 250 Hz, around 500 Hz, and from 0.9 to 2.0 kHz. The goal of this paper is to describe these changes and their effects in lowering vehicle noise levels. 相似文献
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海洋环境立体自动监测系统 总被引：7，自引：0，他引：7
863计划海洋领域海洋监测技术主题“海洋环境立体自动监测系统技术和示范试验”专题（编号818－010是国家863计划“九五”期间重大项目（编号Z40）,在主管部门领导,专家,责任专家的领域,协调和指导下的,经过本专题各课题组主持单位和课题组成员的共同力,已经完成了本专题的研究任务,并通过了由国家863计划联合办公室组织的专家验收,通过本课题的实施,取得了一批有知识产权的高新技术成果,使我国的海洋环境立体自动监测技术与世界发达国家的先进水平的差距缩短了10－15年,达到了90年代中期的国际先进水平,为我国海洋环境监测技术的进一步提高和建立我国整个管辖海域的海洋环境监测服务系统奠定的坚实的技术基础。 相似文献
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A hydrodynamic model of a two-part underwater manoeuvrable towed system is proposed in which a depressor is equipped with active horizontal and vertical control surfaces, and a towed vehicle is attached to the lower end of a primary cable. In such a system the towed vehicle can be manoeuvred in both vertical and horizontal planes when it is towed at a certain velocity and the coupling effect of excitations at the upper end of the primary cable and disturbances of control manipulations to the towed vehicle can be reduced. In the model the hydrodynamic behavior of an underwater vehicle is described by the six-degrees-of-freedom equations of motion for submarine simulations. The added masses of an underwater vehicle are obtained from the three-dimensional potential theory. The control surface forces of the vehicle are determined by the wing theory. The results indicate that with relative simple control measures a two-part underwater manoeuvrable towed system enables the towed vehicle to travel in a wide range with a stable attitude. The method in this model gives an effective numerical approach for determining hydrodynamic characteristics of an underwater vehicle especially when little or no experimental data are available or when costs prohibit doing experiments for determining these data. 相似文献
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Among the fastest‐growing applications of high‐precision GPS positioning are those which are kinematic in nature. Carrier phase‐based GPS positioning of a moving antenna—for example, attached to a ship, an aircraft, or a land vehicle—is now commonplace. Recent software innovations make use of advanced ambiguity resolution “on the fly” and real‐time kinematic data processing algorithms to emulate the ease of operation of conventional differential GPS (DGPS) based on transmitted pseudo‐range corrections. However, as much higher accuracy must now be assured compared to DGPS, greater attention must be focused on the quality control aspects of GPS positioning. This study describes two methods for detecting failures or changes of small magnitude in real time in GPS measurements. Examination of the overlap or disjointedness of robust and conventional confidence intervals and studentized normal variates have been used as failure detection tools. These methods are based on testing the performance of the differences between the conventional (nonrobust) Kalman state estimates and the robust Kalman filler estimates. Detection of cycle slips in carrier phase data, outliers in phase rate or in code ranges, or any other type of disorder in the measurements of the GPS system can be addressed with these failure detection methods. Application and evaluation of the algorithms has been carried out using raw carrier‐phase and phase‐rate GPS measurements. It has been demonstrated that these failure detection tools provide powerful and efficient diagnostics for detecting small changes in the measurements of the GPS system. 相似文献
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Design and projected performance of a flapping foil AUV 总被引：1，自引：0，他引：1
Licht S. Polidoro V. Flores M. Hover F.S. Triantafyllou M.S. 《Oceanic Engineering, IEEE Journal of》2004,29(3):786-794
The design and construction of a biomimetic flapping foil autonomous underwater vehicle is detailed. The vehicle was designed as a proof of concept for the use of oscillating foils as the sole source of motive power for a cruising and hovering underwater vehicle. Primary vehicle design requirements included scalability and flexibility in terms of the number and placement of foils, so as to maximize experimental functionality. This goal was met by designing an independent self-contained module to house each foil, requiring only direct current power and a connection to the vehicle's Ethernet local area network for operation. The results of tests on the foil modules in the Massachusetts Institute of Technology (MIT) Marine Hydrodynamics Water Tunnel and the MIT Ship Model Testing Tank are both used to demonstrate fundamental properties of flapping foils and to predict the performance of the specific vehicle design based on the limits of the actuators. The maximum speed of the vehicle is estimated based on the limitations of the specific actuator and is shown to be a strong function of the vehicle drag coefficient. When using four foils, the maximum speed increases from 1 m/s with a vehicle C/sub D/ of 1.4 to 2 m/s when C/sub D/=0.1, where C/sub D/ is based on vehicle frontal area. Finally, issues of vehicle control are considered, including the decoupling of speed and pitch control using pitch-biased maneuvering and the tradeoff between actuator bandwidth and authority during both the cruising and hovering operation. 相似文献
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航行体近水面滑跳运动是近年来跨介质航行体研究的热点问题之一,针对航行体水面滑跳运动现象开展研究。 首先设计了适宜滑跳的航行体构型,通过数值仿真方法确定航行体的主要技术参数,发现航行体滑跳过程对于重心位置非常敏感;然后,针对设计的构型,开展水面自由滑跳试验,试验表明本文设计的模型可以在近水面稳定滑跳,验证了滑跳运动方式的可行性。 工作可为后续跨介质航行体设计提供技术参考。 相似文献
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Verena M. Trenkel Pascal Lorance 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(1):63-71
Kaup's arrowtooth eel Synaphobranchus kaupii is a small-bodied fish and an abundant inhabitant of the European continental slope. To estimate its local density video information using the remotely operated vehicle (ROV) Victor 6000 were collected at three locations in the Bay of Biscay slope. Two methods for estimating local densities were tested: strip transect counts and bait experiments. For bait experiments three behaviour types were observed in about equal proportions for individuals arriving near the seafloor: moving up the current towards the ROV, moving across the current and drifting with the current. Visible attraction towards the bait was the highest for individuals swimming against the current (80%) and about equally low for the other two types (around 30%); it did not depend on current speed nor temperature. Three main innovations were introduced for estimating population densities from bait experiments: (i) inclusion of an additional behaviour category—that of passively drifting individuals, (ii) inclusion of reaction behaviour for actively swimming individuals and (iii) a hierarchical Bayesian estimation framework. The results indicated that about half of individuals were foraging actively of which less than one third reacted on encountering the bait plume and the other half were drifting with the current. Taking account of drifting individuals and the reaction probability made density estimates from bait experiments and strip transects more similar. 相似文献
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当安装于水下航行体上的旋转装置质量或转动惯量达到一定程度时,其对水下航行体运动与操纵的影响是不可忽略的。针对安装于水下航行体上的旋转装置,分析了水下航行体运动时装置的陀螺效应。得出了旋转装置陀螺力的明确数学方程。不失方法的一般性,假设旋转装置只在运动坐标系的X轴方向有旋转角速度,推导了在考虑陀螺效应作用的情况下水下航行体的六自由度模型方程;以此为基础,建立了水下航行体的仿真模型并对水下航行体的水下运动特性进行了仿真,分析了旋转装置的质量、角速度对水下航行体运动特性的影响规律,从而为研究在考虑陀螺效应情况下的水下航行体操纵奠定了基础。 相似文献
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基于模糊神经网络理论对水下拖曳体进行深度轨迹控制 总被引：2，自引：0，他引：2
以华南理工大学开发的自主稳定可控制水下拖曳体为研究对象,首先通过水下拖曳体在拖曳水池样机中的试验取得试验数据后作为训练样本,采用LM BP算法,建立基于神经网络理论构建的可控制水下拖曳体轨迹与姿态水动力的数值模型。在此基础上设计了一个控制系统,它主要由两部分组成:基于遗传算法的神经网络辨识器和基于模拟退火改进的遗传算法的模糊神经网络控制器。以满足预先设定的拖曳体水下监测轨迹要求为控制依据,由控制系统确定为达到所要求的运动轨迹而应采用的迫沉水翼转角,以此作为输入参数,通过LM BP神经网络模型的模拟计算预报在这一操纵动作控制下的拖曳体所表现的轨迹与姿态特征。数值模拟计算结果表明:该系统的设计达到了所要求的目的;借助这一系统,可以有效地实现对拖曳体的深度轨迹控制。 相似文献
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Wave effects on ascending and descending motions of the autonomous underwater vehicle 总被引：1，自引：0，他引：1
In the paper, a hydrodynamic model including the characteristics of maneuvering and seakeeping is developed to simulate the six-degree of freedom motions of the underwater vehicle steering near the sea surface. The corresponding wave exciting forces on the underwater vehicle moving in waves are calculated by the strip theory, which is based on the source distribution method. With the hydrodynamic coefficients relevant to the maneuvering and seakeeping, the fourth-order Runge–Kutta numerical method is adopted to solve the equations of motions and six-degrees of freedom of the motions for the underwater vehicle steering near the free surface can be obtained. The wave effect on the corresponding motions of the underwater vehicle is investigated and some interesting phenomena with respect to different wave frequencies and headings are observed. The hydrodynamic numerical model developed here can be served as a valuable tool for analyzing the ascending and descending behaviors of the underwater vehicle near the sea surface. 相似文献
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V. V. Dyomin A. L. Olenin I. G. Polovcev D. V. Kamenev A. S. Kozlova A. S. Olshukov 《Oceanology》2018,58(5):749-759
The paper presents the results of marine testing of a digital holographic module for recording and measuring zooplankton. The tests based on the use of measuring-technological platform earlier developed at IO RAS were performed in summer 2016 in the Kara Sea during cruise 66 of the R/V Akademik Mstislav Keldysh. The upper water layer was sensed down to the 240 m horizon, which resulted in successful recording of about 100 Gb of digital holographic frames with reference to continuous depth profiles of electric conductivity in situ. Tests conducted under summer Arctic sea conditions confirmed the validity of the technical solutions. Based on the results, a list of upgrades to the holographic module was compiled for successful implementation of the latter in ocean research. 相似文献
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The selection of the order of an autoregressive process is examined via model-critical methods that allow for constructive criticism of the data and the (tentative) model, considered jointly as a single entity. These methods yield robust estimates of the model parameters and the innovations variance, which is used in the order-selection procedure which reduces as a special case to the modified Akaike-type procedure of Hannan and Quinn. The proposed procedure selects as the order of an autoregressive process the value ofp that minimizes an information criterion PSIC(p, c ) (which is a function of the model-critical parameter (c ) which governs the extent to which data and model are to be internally consistent) the model-critical estimate of the innovations variance, and the sample size. In the presence of additive outliers in the data, the model-critical procedure is superior to the Akaike and Hannan-Quinn procedures, and the superiority increases with increasing levels of contamination. 相似文献
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Hyung-suk HAN 《中国海洋工程》2003,17(3)
1 .IntroductionOnthedeepseabed ,30 0 0～ 50 0 0mbelowthePacificOcean ,manganesenodulesaresolidifiedandspread ,andmanycountriesintheworldarestudyinghowtominethem .AccordingtoYamazakietal.( 1 998)andAmannetal.( 1 991 ) ,theenvironmentofthedeepseabedisdifferentfromthedrylandinmanyways .Inparticular,thesurfaceoftheseabedisverysoft.Inordertoensuretheperformanceofrunningofamanganesenodulemineronsuchasoftsurface ,thetrackedvehiclemaybeapplied .Ac cordingtoHongandChoi ( 2 0 0 1 ) ,astudyisbeingdone… 相似文献
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A three-dimensional model of a two-part underwater towed system is studied. In the model, the governing equations of cables are established based on the Ablow and Schechter method. The boundary conditions for the two-part underwater towed system are derived. The six-degrees-of-freedom equations of motion for submarine simulations are adopted to predict the hydrodynamic performance of a towed vehicle. The established governing equations for the system are then solved using a central finite difference method. In this paper several algorithms are used to solve this special form of finite difference equations. The results in this paper indicate that the two-part underwater towed system improves the dynamic behavior of the towed vehicle and is an easy way to decouple the towing ship motion from the towed vehicle. Because the model uses an implicit time integration, it is stable for large time steps and is an effective algorithm for simulation of a large-scale underwater towed system. 相似文献
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双功能潜水器是目前国际上比较新型的可用于深海水下观察和作业的装备。既可有缆载人／无人，又可无缆载人。该潜水器最大工作深度450m，其结构材料和结构形式与以往类似的装备不同。文章对双功能潜水器耐压壳结构和载体框架设计中的一些问题进行了探讨，提出的设计思想和计算方法，这对获得一个具有最轻结构重量的实用的双功能潜水器结构具有指导意义。 相似文献