由于射频信号的广泛存在,合成孔径雷达(Synthetic Aperture Radar,SAR)在成像的过程中容易受到各类射频干扰(Radio Frequency Interference,RFI)的影响,这会导致获得的SAR图像质量下降,从而对后续的信息提取和目标识别等过程产生很大的...由于射频信号的广泛存在,合成孔径雷达(Synthetic Aperture Radar,SAR)在成像的过程中容易受到各类射频干扰(Radio Frequency Interference,RFI)的影响,这会导致获得的SAR图像质量下降,从而对后续的信息提取和目标识别等过程产生很大的影响。因此,衡量SAR图像受射频干扰的影响程度就尤为重要。然而,现有评估方法的鲁棒性通常较低,并且在评估时未考虑SAR图像受RFI影响的区域大小,因此本文提出了干扰区域⁃强度特征提取与联合评估网络。所提出的网络包含两个模块,干扰强度特征提取模块用于提取输入SAR图像中的干扰强度信息,干扰区域特征提取模块则侧重于干扰区域大小与边界信息的获取。由于SAR图像的尺寸一般比较大,因此本文在干扰强度特征提取模块中采用了多级残差和多层特征融合结构,用于加强模型的特征提取和复用能力;同时在干扰区域特征提取模块中侧重于保留最关键的区域边界特征。此外,本文还建立了SAR受RFI影响的图片数据集用于评估所提出网络的效果。对比实验的结果表明,本文所提出的网络评估结果优于其他现有方法,能够衡量SAR图像受RFI的影响程度,同时具有较高的准确性。展开更多
Soil reinforcement of tree roots is the main mechanical effect of shelter-forest on soil stability and slope protection, and the traction effect of lateral roots plays an important role in this concern in mountainous ...Soil reinforcement of tree roots is the main mechanical effect of shelter-forest on soil stability and slope protection, and the traction effect of lateral roots plays an important role in this concern in mountainous areas. The magnetite of this role rises positively with the tensile strength of the roots in the soil. This study developed a mechanical model of relationship between the tensile strength of roots and the traction effect used in pine forests. The results showed that the tensile strength of the pines mostly lays in a range of 5～25MPa, and decreased with diameter of the roots. In the depth interval of 0～60cm, the density of lateral roots of the three pines is relatively high, and the roots are able to increase the tensile strength of the rooted soil by 6 85～9 50 kPa, through traction effect. Though the strength of the pine roots and its role in increasing strength of the rooted soil are significant, the strength of the pines is lower than those of some broad leaved trees. This means that the pines have certain limitation on their role of shallow slope stability.展开更多
文摘由于射频信号的广泛存在,合成孔径雷达(Synthetic Aperture Radar,SAR)在成像的过程中容易受到各类射频干扰(Radio Frequency Interference,RFI)的影响,这会导致获得的SAR图像质量下降,从而对后续的信息提取和目标识别等过程产生很大的影响。因此,衡量SAR图像受射频干扰的影响程度就尤为重要。然而,现有评估方法的鲁棒性通常较低,并且在评估时未考虑SAR图像受RFI影响的区域大小,因此本文提出了干扰区域⁃强度特征提取与联合评估网络。所提出的网络包含两个模块,干扰强度特征提取模块用于提取输入SAR图像中的干扰强度信息,干扰区域特征提取模块则侧重于干扰区域大小与边界信息的获取。由于SAR图像的尺寸一般比较大,因此本文在干扰强度特征提取模块中采用了多级残差和多层特征融合结构,用于加强模型的特征提取和复用能力;同时在干扰区域特征提取模块中侧重于保留最关键的区域边界特征。此外,本文还建立了SAR受RFI影响的图片数据集用于评估所提出网络的效果。对比实验的结果表明,本文所提出的网络评估结果优于其他现有方法,能够衡量SAR图像受RFI的影响程度,同时具有较高的准确性。
文摘Soil reinforcement of tree roots is the main mechanical effect of shelter-forest on soil stability and slope protection, and the traction effect of lateral roots plays an important role in this concern in mountainous areas. The magnetite of this role rises positively with the tensile strength of the roots in the soil. This study developed a mechanical model of relationship between the tensile strength of roots and the traction effect used in pine forests. The results showed that the tensile strength of the pines mostly lays in a range of 5～25MPa, and decreased with diameter of the roots. In the depth interval of 0～60cm, the density of lateral roots of the three pines is relatively high, and the roots are able to increase the tensile strength of the rooted soil by 6 85～9 50 kPa, through traction effect. Though the strength of the pine roots and its role in increasing strength of the rooted soil are significant, the strength of the pines is lower than those of some broad leaved trees. This means that the pines have certain limitation on their role of shallow slope stability.
