Vanzella Walter, Pellegrino Felice Andrea, Torre Vincent
Neurobiology Sector, SISSA/ISAS, Via Beirut 7, Trieste, Italy.
IEEE Trans Pattern Anal Mach Intell. 2004 Jun;26(6):804-9. doi: 10.1109/TPAMI.2004.15.
Often an image g(x,y) is regularized and even restored by minimizing the Mumford-Shah functional. Properties of the regularized image u(x,y) depends critically on the numerical value of the two parameters alpha and gamma controlling smoothness and fidelity. When alpha and gamma are constant over the image, small details are lost when an extensive filtering is used in order to remove noise. In this paper, it is shown how the two parameters alpha and gamma can be made self-adaptive. In fact, alpha and gamma are not constant but automatically adapt to the local scale and contrast of features in the image. In this way, edges at all scales are detected and boundaries are well-localized and preserved. In order to preserve trihedral junctions alpha and gamma become locally small and the regularized image u(x,y) maintains sharp and well-defined trihedral junctions. Images regularized by the proposed procedure are well-suited for further processing, such as image segmentation and object recognition.
通常,图像g(x,y)通过最小化Mumford-Shah泛函进行正则化甚至恢复。正则化图像u(x,y)的属性严重依赖于控制平滑度和保真度的两个参数α和γ的数值。当α和γ在图像上恒定时,为了去除噪声而进行广泛滤波时会丢失小细节。本文展示了如何使α和γ这两个参数自适应。实际上,α和γ不是恒定的,而是自动适应图像中特征的局部尺度和对比度。通过这种方式,可以检测到所有尺度的边缘,边界也能很好地定位和保留。为了保留三面体连接,α和γ在局部变小,正则化图像u(x,y)保持尖锐且定义明确的三面体连接。通过所提出的过程进行正则化的图像非常适合进一步处理,如图像分割和目标识别。