针对高实时性要求中SURF(speeded up robust features)特征匹配算法速度偏慢的缺点,提出一种基于分块的加速方法,根据匹配中模板图像与搜索图像的大小对比关系,分别采用只对搜索图像分块的单分块方法与对模板图像与搜索图像都进行分块...针对高实时性要求中SURF(speeded up robust features)特征匹配算法速度偏慢的缺点,提出一种基于分块的加速方法,根据匹配中模板图像与搜索图像的大小对比关系,分别采用只对搜索图像分块的单分块方法与对模板图像与搜索图像都进行分块的双分块方法,其中单分块方法包括简单K分块、简单K+1分块、尺度K+1分块及模板尺寸与尺度自适应的分块方法;双分块方法包括单块匹配与多块匹配。针对不同的分块方法分析了其理论上的平均匹配时间,并通过实验进行了对比,结果证明分块方法能够在保证正确匹配的同时大幅提高匹配速度。展开更多
Improvement of transportation infrastructure quality will lead to more sufficient market competition and promote the flow of resources with greater efficiency. This paper considers China's railway speed-up in 2007...Improvement of transportation infrastructure quality will lead to more sufficient market competition and promote the flow of resources with greater efficiency. This paper considers China's railway speed-up in 2007 as a quasi-natural experiment on China's transportation infrastructure quality improvement. With the initial operation of electric multiple units(EMUs) as the basis of grouping, this research examines the effect of railway speed-up on corporate total factor productivity(TFP) growth by the differencein-differences(DID) method. Overally, the results reveal positive effects both on firms' technological change and efficiency improvement, which lead to the increase of TFP. Based on subsamples divided by different regions and types of enterprises, further analysis indicates that the productivity of exporter, non-state and coastal firms has been mostly affected by the railway speed-up. These conclusions are verified by a placebo test. Besides, firms within "one-hour economic circle" have been shown more sensitive to the effect of railway speed increase.展开更多
文摘针对高实时性要求中SURF(speeded up robust features)特征匹配算法速度偏慢的缺点,提出一种基于分块的加速方法,根据匹配中模板图像与搜索图像的大小对比关系,分别采用只对搜索图像分块的单分块方法与对模板图像与搜索图像都进行分块的双分块方法,其中单分块方法包括简单K分块、简单K+1分块、尺度K+1分块及模板尺寸与尺度自适应的分块方法;双分块方法包括单块匹配与多块匹配。针对不同的分块方法分析了其理论上的平均匹配时间,并通过实验进行了对比,结果证明分块方法能够在保证正确匹配的同时大幅提高匹配速度。
基金supported by the National Social Science Foundation of China (NSFC) programs (14CJL020, 15CJL048)the Humanity and Social Science Youth Foundation Program of Ministry of Education of China (15YJC790006)
文摘Improvement of transportation infrastructure quality will lead to more sufficient market competition and promote the flow of resources with greater efficiency. This paper considers China's railway speed-up in 2007 as a quasi-natural experiment on China's transportation infrastructure quality improvement. With the initial operation of electric multiple units(EMUs) as the basis of grouping, this research examines the effect of railway speed-up on corporate total factor productivity(TFP) growth by the differencein-differences(DID) method. Overally, the results reveal positive effects both on firms' technological change and efficiency improvement, which lead to the increase of TFP. Based on subsamples divided by different regions and types of enterprises, further analysis indicates that the productivity of exporter, non-state and coastal firms has been mostly affected by the railway speed-up. These conclusions are verified by a placebo test. Besides, firms within "one-hour economic circle" have been shown more sensitive to the effect of railway speed increase.
