针对环境复杂的工业现场中自主定位精度低、适应性差的问题,提出一种结合人工信标和视觉的同时定位与地图构建(Simultaneous localization and mapping,SLAM)的双相机定位系统。人工信标无需覆盖全空间布置,无需具备ID信息,通过两台相...针对环境复杂的工业现场中自主定位精度低、适应性差的问题,提出一种结合人工信标和视觉的同时定位与地图构建(Simultaneous localization and mapping,SLAM)的双相机定位系统。人工信标无需覆盖全空间布置,无需具备ID信息,通过两台相机分别拍摄信标及运行视觉SLAM算法完成全空间定位,利用信标定位算法恢复单目SLAM的尺度不确定因子并且建立起两种定位算法坐标系之间的关系,因此当相机视场由信标组成的控制场覆盖范围外再次移回其覆盖范围内时,可通过SLAM算法得到的系统位姿初值实现信标和像点的快速匹配,从而再次精确定位。将双相机定位系统安装在可穿戴的头盔上,测量人员头戴头盔便可实现高精度定位。分析了双相机头盔定位系统的工作原理,并进行了试验验证。试验结果表明,该方法精度较高、适应性强,可满足在信标无法全空间覆盖的复杂工业环境下的自主定位需求。展开更多
Abstract Inter-simple sequence repeat （ISSR） markers were used to determine the genetic variation and genetic differentiation of cultured and wild populations of Trachidermus fasciatus, an endangered catadromous fis...Abstract Inter-simple sequence repeat （ISSR） markers were used to determine the genetic variation and genetic differentiation of cultured and wild populations of Trachidermus fasciatus, an endangered catadromous fish species in China. Six selected primers were used to amplify DNA samples from 85 individuals, and 353 loci were detected. Relatively low genetic diversity was detected in the cultured population （the percentage of polymorphic loci PPL=73.80%, Nei＇s gene diversity h--0.178 2, Shannon information index I=0.276 9）. However, the genetic diversity at the species level was relatively high （PPL-91.78%; h = 0.258 3, I= 0.398 6）. The UPGMA tree grouped together the genotypes almost according to their cultured and wild origin, showing distinct differences in genetic structure between wild and cultured populations. The pairwise F^t values confirmed significant genetic differentiation between wild and cultured samples. The cultivated population seems to be low in genetic diversity as a result of detrimental genetic effects in the captive population. The results suggest that ISSR markers are effective for rapid assessment of the degree of diversity of a population, thus giving important topical information relevant to preserving endangered species.展开更多
文摘针对环境复杂的工业现场中自主定位精度低、适应性差的问题,提出一种结合人工信标和视觉的同时定位与地图构建(Simultaneous localization and mapping,SLAM)的双相机定位系统。人工信标无需覆盖全空间布置,无需具备ID信息,通过两台相机分别拍摄信标及运行视觉SLAM算法完成全空间定位,利用信标定位算法恢复单目SLAM的尺度不确定因子并且建立起两种定位算法坐标系之间的关系,因此当相机视场由信标组成的控制场覆盖范围外再次移回其覆盖范围内时,可通过SLAM算法得到的系统位姿初值实现信标和像点的快速匹配,从而再次精确定位。将双相机定位系统安装在可穿戴的头盔上,测量人员头戴头盔便可实现高精度定位。分析了双相机头盔定位系统的工作原理,并进行了试验验证。试验结果表明,该方法精度较高、适应性强,可满足在信标无法全空间覆盖的复杂工业环境下的自主定位需求。
基金Supported by the Key Laboratory of Freshwater Biodiversity Conservation and Utilization, Ministry of Agriculture (No. LFBCU0713)the Special Research Foundation for Public Welfare Marine Program (No. 200905019-2)
文摘Abstract Inter-simple sequence repeat （ISSR） markers were used to determine the genetic variation and genetic differentiation of cultured and wild populations of Trachidermus fasciatus, an endangered catadromous fish species in China. Six selected primers were used to amplify DNA samples from 85 individuals, and 353 loci were detected. Relatively low genetic diversity was detected in the cultured population （the percentage of polymorphic loci PPL=73.80%, Nei＇s gene diversity h--0.178 2, Shannon information index I=0.276 9）. However, the genetic diversity at the species level was relatively high （PPL-91.78%; h = 0.258 3, I= 0.398 6）. The UPGMA tree grouped together the genotypes almost according to their cultured and wild origin, showing distinct differences in genetic structure between wild and cultured populations. The pairwise F^t values confirmed significant genetic differentiation between wild and cultured samples. The cultivated population seems to be low in genetic diversity as a result of detrimental genetic effects in the captive population. The results suggest that ISSR markers are effective for rapid assessment of the degree of diversity of a population, thus giving important topical information relevant to preserving endangered species.
