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1.
针对光照变化和大位移运动等复杂场景下图像序列变分光流计算的边缘模糊与过度分割问题,文中提出基于运动优化语义分割的变分光流计算方法.首先,根据图像局部区域的去均值归一化匹配模型,构建变分光流计算能量泛函.然后,利用去均值归一化互相关光流估计结果,获取图像运动边界信息,优化语义分割,设计运动约束语义分割的变分光流计算模型.最后,融合图像不同标签区域光流,获得光流计算结果.在Middlebury、UCF101数据库上的实验表明,文中方法的光流估计精度与鲁棒性较高,尤其对光照变化、弱纹理和大位移运动等复杂场景的边缘保护效果较优.  相似文献   
2.
水库蓄水量研究对于合理保护和利用水资源具有重要的指导意义.针对水库蓄水量估算研究现状和不足,使用星载雷达高度计(RA)提取水库的遥测水位,利用星载多光谱成像仪(MSI)和星载合成孔径雷达(SAR)提取水库的水域面积,基于数据同化技术建立了多源遥感水库蓄水量估算模型,并开发了一款多源遥感水库蓄水量估算系统.该系统可以无接触地获取遥测水位和水域面积并估算蓄水量,具有稳定性、通用性等特点,有望应用于防汛抗旱、水库调度等领域,为管理部门科学化、高效化管理水库提供技术支撑.  相似文献   
3.
Octopus (Optics Clustered to OutPut Unique Solutions) celebrated in June 2020 its 10th birthday. Based at Harwell, near Oxford, Octopus is an open access, peer reviewed, national imaging facility that offers successful U.K. applicants supported access to single molecule imaging, confocal microscopy, several flavours of superresolution imaging, light sheet microscopy, optical trapping and cryoscanning electron microscopy. Managed by a multidisciplinary team, Octopus has so far assisted >100 groups of U.K. and international researchers. Cross‐fertilisation across fields proved to be a strong propeller of success underpinned by combining access to top‐end instrumentation with a strong programme of imaging hardware and software developments. How Octopus was born, and highlights of the multidisciplinary output produced during its 10‐year journey are reviewed below, with the aim of celebrating a myriad of collaborations with the U.K. scientific community, and reflecting on their scientific and societal impact.  相似文献   
4.
A photovoltaic system could supply a single-family house with electrical power, warm water, and room heat if the energy would be distributed over the year to suit the load profile. However, storage systems for this are not state of the art yet. A concrete example is used to estimate which parameters such a power storage system should have. A suitable electrochemical reaction system based on inorganic salt mixtures is proposed. The German Federal Ministry of Education and Research is currently funding the development of a world storage facility based on the same reaction system.  相似文献   
5.
The effect of cross‐flow filtration of liquids relies on the continuous and controlled circulation of fluids in linear channels. The flow rate is of crucial importance to the economy of the process. TAMI Industries is investigating the use of so‐called additive processes to produce ceramic supports with geometric structures that cannot be produced using traditional technologies. In comparison to conventional geometries, it is possible to increase the permeate output without increasing the energy consumption or correspondingly reducing the energy consumption at the same permeate output.  相似文献   
6.
雷达高度计的主要功能是测量全球平均海平面高度(SSH:Sea Surface Height),它通过准确测量收发脉冲之间的时间间隔来实现精准的星地距离测量,时间测量的准确度取决于高度计时钟的准确性。卫星在轨运行期间,雷达高度计时钟频率会产生缓慢漂移,时钟频率漂移会影响星地距离的测量准确度,造成对海面高程的测量偏差。在基于重建型有源定标器对HY-2A卫星高度计时钟偏差在轨测试方法的基础上,提出了从星地斜距函数曲线时间偏移量中提取高度计时钟偏差的估计方法,应用于HY-2B卫星雷达高度计在轨定标测试中,测量了雷达高度计时钟频率漂移量,精度优于0.001 Hz。结果表明:HY-2B高度计原子钟性能稳定,时钟频率偏差造成的测距偏差为毫米量级,平均测距漂移率为2.95×10-7 m/d。  相似文献   
7.
近年来无锚框的目标检测算法逐渐被应用于SAR舰船检测,其中FCOS算法摆脱了对锚框参数设置的依赖,对多尺度、多形态舰船检测的鲁棒性更好,但仍存在两个问题:第一、该算法直接进行逐像素点回归,因搜索空间过大、目标回归困难导致检测不够准确;第二、其中特征金字塔对低层特征利用仍有不足导致小目标大量漏检。针对上述问题基于FCOS进行改进,通过增加特征增强网络构建了二阶段无锚框检测算法。该网络作为第一阶段对检测过程进行精细化引导,同时增强了舰船特征表达能力。通过引入更多特征并增加跳跃连接改进特征金字塔,提高了低层特征利用率。在数据集SSDD和SAR-Ship-Dataset上的实验结果表明,平均准确率(mAP)相比FCOS分别提高9.5和3.4个百分点,相比其他主流舰船检测算法分别提高3.6和1.0个百分点,充分验证了所提算法的有效性。  相似文献   
8.
Lake changes have great impacts on local and regional ecosystems and socioeconomic activities. To determine the recent changes in Hongze Lake, radar altimeter and Landsat data were used to examine the water level and area and estimate the water volume changes from 2003 to 2018. Generally, the annual water level results from radar altimeter data showed good agreement with in situ measurements (r2 = 0.62, bias = −0.02 m, mean absolute error = 0.10 m and root mean square error = 0.12 m). Although the results show that the water level and water volume of Hongze Lake had no trends during the 16 years, the water area decreased significantly at a rate of 19.76 km2 per year. Despite great fluctuations throughout 16 years, two shifts occurred in approximately 2007 and 2013. The water level, area and volume of Hongze Lake decreased from 2007 to 2012, but they all showed increasing trends after 2013. The interannual changes in the water level and volume of Hongze Lake were consistent with the changes in annual precipitation, while the change in area was mainly affected by human activities, especially land reclamation and aquaculture activities along the lakeshore. In addition, the intra-annual change in the water level was greatly affected by artificial activities such as irrigation and flood prevention.  相似文献   
9.
Electricity-based fuels are one promising option to achieve the transition of the energy system, and especially the transport sector, in order to minimize the role of fossil energy carriers. One major problem is the lacking compatibility between different techno-economic assessments, such that recommendations regarding the most promising Power-to-Fuel technology are difficult to make. This work provides a technically sound comparison of various Power-to-Fuel options regarding technological maturity and efficiency, as well as cost. The investigated options include methanol, ethanol, butanol, octanol, DME, OME3-5 and hydrocarbons. To guarantee the comparability, all necessary chemical plants were designed in Aspen Plus® to determine material and energy consumption, as well as investment costs within the same boundary conditions and assumptions in all simulations and calculations. Individual technical aspects of the various synthesis routes, as well as their advantages and disadvantages, are highlighted.With an assumed electrolysis efficiency of 70% and considering the energy demand for the CO2 supply and the energy and operating material demand of the chemical plants, depending on the selected electrofuel, 30–60% of the primary energy in renewable electricity can be stored in the lower heating value of the electrofuel. In the presented results, the costs of H2 supply are responsible for 58–83% of the total manufacturing costs and thus have the greatest potential to reduce the latter. For the base case (4.6 €/kgH2), various electrofuels will have costs of manufacturing of between 1.85 and 3.96 €/lDE, with DME being the cheapest.  相似文献   
10.
南非是我国的重要矿业合作伙伴之一,其矿业技术发展演变过程和现行鼓励矿业技术研究的政策和计划对于我国矿业主管部门、研究教育机构和企业有一定的参考价值。本文结合矿业技术专利和矿山机械进出口数据对南非矿业技术的发展历史和现状进行了分析,调研了南非矿业研发活动的主要参与者、与矿业研究有关的主要政策、计划和项目,提出了借南非矿业景气下滑之机,利用中南政府间科技合作项目、金砖国家新开发银行等平台和渠道,加强中南矿业技术合作、吸纳南非优秀人才的建议。  相似文献   
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