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一种提高三维医学数据场边缘过渡区域图像质量的算法 被引量:1
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作者 黎新伍 郝重阳 +2 位作者 李书印 张先勇 樊养余 《西北工业大学学报》 EI CAS CSCD 北大核心 2003年第3期329-331,共3页
在对医学三维数据场模糊特性的分析基础上 ,提出了一种提高三维医学数据场边界过渡区域图像质量的体元投射算法。论文详细说明了算法流程 ,包括特征区域的提取方法和基于体元合并的数据场绘制方法。实验表明 ,算法既提高了过渡区的图像... 在对医学三维数据场模糊特性的分析基础上 ,提出了一种提高三维医学数据场边界过渡区域图像质量的体元投射算法。论文详细说明了算法流程 ,包括特征区域的提取方法和基于体元合并的数据场绘制方法。实验表明 ,算法既提高了过渡区的图像质量 。 展开更多
关键词 边界过渡区 三维医学数据场 体元合并
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一种基于医学三维数据场模糊分割的体元投射算法 被引量:3
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作者 黎新伍 马苗 《系统仿真学报》 EI CAS CSCD 北大核心 2005年第8期1922-1923,1935,共3页
论证了医学三维数据场边界过渡区域的存在性,并提出了一个修正体元投射算法。该方法先对三维数据场进行归一、整数化的预处理,并修正扩展二维图像的分割方法,使之适用于提取三维数据场边界过渡区。在此基础上将三维数据场非此即彼的分... 论证了医学三维数据场边界过渡区域的存在性,并提出了一个修正体元投射算法。该方法先对三维数据场进行归一、整数化的预处理,并修正扩展二维图像的分割方法,使之适用于提取三维数据场边界过渡区。在此基础上将三维数据场非此即彼的分类优化为将数据场分为边界过渡区域和非边界过渡区域的模糊分割,再分别予以不同的体元投射绘制。最后给出的实验结果表明,算法既可以提高了数据场过渡区域的图像质量,又可以保证图像的绘制速度。 展开更多
关键词 边界过渡区 三维数据场 体元投射 模糊分割
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Boundary Shift of Potential Suitable Agricultural Area in Farming-grazing Transitional Zone in Northeastern China under Background of Climate Change During 20th Century 被引量:3
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作者 YE Yu FANG Xiuqi 《Chinese Geographical Science》 SCIE CSCD 2013年第6期655-665,共11页
Climate change affected the agricultural expansion and the formation of farming-grazing transitional patterns during historical periods. This study analyzed the possible range of the boundary shift of the potential su... Climate change affected the agricultural expansion and the formation of farming-grazing transitional patterns during historical periods. This study analyzed the possible range of the boundary shift of the potential suitable agriculture area in the farming-grazing transitional zone in the northeastern China during the 20th century. Based on modem weather data, 1 km-resolution land cover data, historical climatic time series, and estimation by using similar historical climatic scenes, the following was concluded: 1) The climate conditions of suitable agriculture areas in the farming-grazing transitional zone in the northeastern China between 1971 and 2000 required an average annual temperature above 1℃ or ≥ 0℃ accumulated temperature above 2500℃-2700℃, and annual precipitation above 350 mm. 2) The northern boundary of the potential suitable agriculture area during the relatively warmer period of 1890-1910 was approximately located at the position of the 1961-2000 area. The northern boundary shifted back to the south by 75 km on average during the colder period of the earlier 20th century, whereas during the modem warm period of the 1990s, the area shifted north by 100 km on average. 3) The western and eastern boundaries of the suitable agricul^re area during the heaviest drought periods between 1920s and 1930s had shifted northeast by 250 km and 125 km, respectively, contrasting to the boundaries of 1951-2008. For the wettest period, that is, the 1890s to the 1910s, the shift of western and eastern boundaries was to the southwest by 125 km and 200 km, respectively, compared with that in the 1951-2008 period. This study serves as a reference for identifying a climatically sensitive area and planning future land use and agricultural production in the study area. 展开更多
关键词 land cover changes farming-grazing transitional zone climate change agricultural production
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