Image-based topographic recognition on natural terrain

This paper proposes a direct geographic recognition scheme from a gray-scale image without shape reconstruction. Several geographic categories are expressed in 3 × 3-arrays of normal-vector directions. Only by looking up a table, the observed pixel-values (intensities) in a window are transformed into indices of conformity whether the scene in the window is due to each geographic category or not. Geographical features are extracted by multi-resolution interpretation and fuzzy-logical operations. The feasibility and robustness of the proposed method is shown by some computer simulations