Patent ID: 7046841
Filing Date: 2006-05-16
Classification: G01C,G01S,G06K

Abstract:
1. A method for processing digital image data taken from a three-dimensional topographic scene including terrain to extract discrete objects, the method comprising: locating waypoints to define a centerline and a bounded area to be analyzed; defining the primary dimensional characteristics or attributes of the objects to be extracted from the image; defining finite element cells having a width dependent on the area of interest, a length dependent on the dimension of the objects and terrain variation and a height dependent on the discrete objects; mapping the finite element cells to a normalized coordinate base; grouping the digital image data, in the form of scanned three-dimensional point (x, y, z) coordinate points in Cartesian coordinate reference frames, into the finite element cells by determining eigenvalues and eigenvectors associated with each cell; classifying each of the three-dimensional points as simple local structures; composing globally complex structures from the local structures; and wherein spatial relationships of the three-dimensional coordinate points within each finite element cell are analyzed by calculating a 3×3 covariance matrix where C calculating the eigenvalues and eigenvectors of the matrix, each eigenvector {right arrow over (e)}and corresponding eigenvalue λ satisfying the equation: wherein C is a constant, and such that the three eigenvalues measure the spread of the data in the direction of the corresponding eigenvectors.