Gradient vector flow （GVF） is an effective external force for active contours, but its iso- tropic nature handicaps its performance. The recently proposed gradient vector flow in the normal direction （NGVF） is ani...Gradient vector flow （GVF） is an effective external force for active contours, but its iso- tropic nature handicaps its performance. The recently proposed gradient vector flow in the normal direction （NGVF） is anisotropic since it only keeps the diffusion along the normal direction of the isophotes; however, it has difficulties forcing a snake into long, thin boundary indentations. In this paper, a novel external force for active contours called normally generalized gradient vector flow （NGGVF） is proposed, which generalizes the NGVF formulation to include two spatially varying weighting functions. Consequently, the proposed NGGVF snake is anisotropic and would improve ac- tive contour convergence into long, thin boundary indentations while maintaining other desirable properties of the NGVF snake, such as enlarged capture range, initialization insensitivity and good convergence at concavities. The advantages on synthetic and real images are demonstrated.展开更多
针对各向异性扩散冲击滤波器(ADSF)在图像增强中对噪声敏感的问题,将梯度矢量流(GVF)引入到ADSF中,提出一种新的图像去噪方法 GVF-ADSF。在改进的GVF-ADSF方法中,通过引入曲率差来区分图像的特征区域,并定义一个加权系数来控制滤波器中...针对各向异性扩散冲击滤波器(ADSF)在图像增强中对噪声敏感的问题,将梯度矢量流(GVF)引入到ADSF中,提出一种新的图像去噪方法 GVF-ADSF。在改进的GVF-ADSF方法中,通过引入曲率差来区分图像的特征区域,并定义一个加权系数来控制滤波器中2个扩散项在图像的边缘区域和平坦区域的扩散程度,使得图像区域之间能够自然的平滑过渡。通过实验对比本文方法与均值滤波、Perona and Mailk(PM)模型、ADSF模型的去噪性能,结果表明所提方法能很好地去除图像噪声并保留图像丰富的纹理细节,得到更高的信噪比。展开更多
基金Supported by the National Natural Science Foundation of China(60805004)the State Key Lab of Space Medicine Fundamen-tals and Application(SMFA09A16)
文摘Gradient vector flow （GVF） is an effective external force for active contours, but its iso- tropic nature handicaps its performance. The recently proposed gradient vector flow in the normal direction （NGVF） is anisotropic since it only keeps the diffusion along the normal direction of the isophotes; however, it has difficulties forcing a snake into long, thin boundary indentations. In this paper, a novel external force for active contours called normally generalized gradient vector flow （NGGVF） is proposed, which generalizes the NGVF formulation to include two spatially varying weighting functions. Consequently, the proposed NGGVF snake is anisotropic and would improve ac- tive contour convergence into long, thin boundary indentations while maintaining other desirable properties of the NGVF snake, such as enlarged capture range, initialization insensitivity and good convergence at concavities. The advantages on synthetic and real images are demonstrated.
文摘针对各向异性扩散冲击滤波器(ADSF)在图像增强中对噪声敏感的问题,将梯度矢量流(GVF)引入到ADSF中,提出一种新的图像去噪方法 GVF-ADSF。在改进的GVF-ADSF方法中,通过引入曲率差来区分图像的特征区域,并定义一个加权系数来控制滤波器中2个扩散项在图像的边缘区域和平坦区域的扩散程度,使得图像区域之间能够自然的平滑过渡。通过实验对比本文方法与均值滤波、Perona and Mailk(PM)模型、ADSF模型的去噪性能,结果表明所提方法能很好地去除图像噪声并保留图像丰富的纹理细节,得到更高的信噪比。
