The corrosion surface of hot-dip galvanized steel is regarded to be fractal and contains abundant self-similar information. In most cases, the corrosions of surface are not uniform as considered. For such an uneven eroded surface, regional fractals are introduced here in order to improve the analysis accuracy for local corrosions. Basing on the singular value decomposition of surface image, fractal dimensions of the energy norm along with the energy scale are analyzed. Combining energy norm of singular values and wavelet transform, the corrosion surfaces are described in different scales and decomposed levels.