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Automatic Road Extraction in Rural Areas Based on Digital Imaging and Laser Scanner Data
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作者 Claudionor Ribeiro da Silva Jorge Ant6nio Silva Centeno Maria Joao Henriques 《Journal of Civil Engineering and Architecture》 2011年第4期285-296,共12页
Digitizing road maps manually is an expensive and time-consuming task. Several methods that intend to develop fully or semi-automated systems have been proposed. In this work we introduce a method, based on the Radon ... Digitizing road maps manually is an expensive and time-consuming task. Several methods that intend to develop fully or semi-automated systems have been proposed. In this work we introduce a method, based on the Radon transform and optimal algorithms, which extracts automatically roads on images of rural areas, images that were acquired by digital cameras and airborne laser scanners. The proposed method detects linear segments iteratively and starting from this it generates the centerlines of the roads. The method is based on an objective function which depends on three parameters related to the correlation between the cross-sections, spectral similarity and directions of the segments. Different tests were performed using aerial photos, Ikonos images and laser scanner data of an area located in the state of Parana (Brazil) and their results are presented and discussed. The quality of the detection of the roads centerlines was computed using several indexes - completeness, correctness and RMS. The values obtained reveal the good performance of the proposed methodology. 展开更多
关键词 Radon transform automatic extraction ROADS laser scanning digital image
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自然课的学法指导
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作者 周友富 《人民教育》 北大核心 1991年第10期39-39,共1页
小学自然课在教学中最忌灌输。教师应善于引导学生独立地进行学习。因此,在自然教学中加强学法指导十分必要。我认为,小学自然的学法指导应在三个方面下功夫。
关键词 学法指导 发展顺序 身体特征 投影片 在三 景善 荷梗 观察重点 结构顺序 星图仪
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该死的进化
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作者 罗洪斌 《世界科幻博览》 2005年第5期60-61,共2页
当艾伦皮包骨头的血肉之躯被置换成机械之躯时,艾伦兴奋无比,这意味着他再也不用在贫民窟里受穷挨饿整天为生计奔命了。他那蓝眼睛里满是幸福的阳光。几个"好心"的富人为他身体的置换付了账,交换条件是让他参加星际探险,寻找... 当艾伦皮包骨头的血肉之躯被置换成机械之躯时,艾伦兴奋无比,这意味着他再也不用在贫民窟里受穷挨饿整天为生计奔命了。他那蓝眼睛里满是幸福的阳光。几个"好心"的富人为他身体的置换付了账,交换条件是让他参加星际探险,寻找外星人。"什么,要去宇宙找外星人?那我就是宇航员了!!!"艾伦激动不已,一把抱住在贫民窟里老跟他抢食吃的大老黑,热情地亲吻着他并和他跳舞。啊,童年的梦想,竟在此时一步登天地实现啦! 展开更多
关键词 艾伦 里老 交换条件 想当年 给你 星图仪 海蓝色 没理会 转了 地冲
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Satellite remote sensing of volcanic ash cloud in complicated meteorological conditions 被引量:2
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作者 ZHU Lin LIU Jian +1 位作者 LIU Cheng WANG Meng 《Science China Earth Sciences》 SCIE EI CAS 2011年第11期1789-1795,共7页
Volcanic ash cloud has serious impacts on aviation.With volcanic ash dispersion,it also has a profound and long-term impact on climate and the environment.A new volcanic ash cloud detecting method (SWIR-TIR Volcanic A... Volcanic ash cloud has serious impacts on aviation.With volcanic ash dispersion,it also has a profound and long-term impact on climate and the environment.A new volcanic ash cloud detecting method (SWIR-TIR Volcanic Ash method,STVA) is presented that uses satellite images of Medium Resolution Spectral Imager (MERSI) and Visible and Infrared Radiometer (VIRR) on board the second generation Polar-Orbiting meteorological satellite of China (FY-3A).STVA is applied in detecting Iceland's Eyjafjallajokull volcano eruption.Compared with the traditional Split Window Temperature Difference method (SWTD),the results show that STVA is more sensitive to volcanic ash cloud than SWTD and can fairly extract volcanic ash information from the background of meteorological cloud and the ocean.Ash Radiance Index (ARI) and Absorbing Aerosol Index (AAI) derived from Metop-A satellite images are used to validate the performance of STVA.It is shown that STVA provides similar results with ARI and AAI.FY-3A/MERSI,VIRR and Terra /MODIS data are used to test STVA and SWTD.It is demonstrated that STVA derived from FY-3A satellite data is more effective in complicated meteorological conditions.This study shows great potential of using China's own new generation satellite data in future global volcanic ash cloud monitoring operation. 展开更多
关键词 FY-3A/MERSI FY-3A/VIRR volcanic ash cloud Split Window Temperature Difference method SWIR-TIR VolcanicAsh method
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