Patent ID: 8238658

Claim:
A computer-implemented method for extracting an ordered shoreline from a digital image, comprising: receiving a set of water data comprising a plurality of pixel locations indicative of a presence of water in the image; receiving a set of edge data comprising a plurality of pixel locations indicative of a land-water interface in the image; transforming the edge data into a set of mean edge data points e i ; transforming the mean edge data points into a plurality of 3-point boundary segments, each 3-point boundary segment comprising a mean edge data point e i and its two nearest neighbor mean edge points e i−1 and e i+1 ; determining a mean normalized water direction vector originating at each mean edge data point e i , the mean normalized water direction vector pointing from e i towards the center of the water; taking a first cross-product of the mean normalized water direction vector with each of a head vector and a tail vector extending between e i and e i−1 and taking a second cross product of the mean normalized feature direction vector with each of a head vector and a tail vector extending between e i and e i+1 ; assigning one of a head and a tail to e i based on the results of the first and second cross-products and a predetermined one of a clockwise and a counterclockwise direction of the shoreline; transforming the data of each mean edge data point e i , its associated one of a head and a tail and its nearest neighbors e i−1 and e i+1 into a set of ordered shoreline boundary segments; and joining the set of ordered shoreline boundary segments to form the shoreline.