| 主权项 |
1. A method for automatically determining contours of heights of a relief, of a geographical area (ZO), the method comprising:
a) on the basis of an image of said geographical area (ZO), which contains altimetric data of points therein, a background surface of the relief which illustrates gradual variations in altitudes of said geographical area (ZO) is eliminated, by implementing a top hat algorithm, which uses a structuring element (28) which is adjustable; b) on the basis of step a), thresholding is performed on the image of said geographical area (ZO) to form a binary image (IB) of the relief seen from above, containing only reliefs having heights above a threshold value which is adjustable, wherein the threshold value is calculated using a noise tolerance parameter wherein T=k−σ, wherein k is a coefficient of standard deviation and a is the standard deviation of altitudes in the altimetric data; c) from this binary image (IB) which comprises two different types (Z1, Z2) of area, rough contours of the heights of the relief are extracted, illustrating the boundaries between these two different types (Z1, Z2) of area; and d) said rough contours are simplified so as to obtain a set of polygons (P1, P2, P3) illustrating the contours (C1, C2, C3) of the heights of the relief of said geographical area (Z0). |
