Patent ID: 6985625

Claim:
A method for forming chains of edgelets, the edgelets being disposed within a two-dimensional array, each edgelet having a position and a direction, the method comprising: for each edgelet, providing a data structure including data slots for storing: edgelet position, edgelet direction, a right link to a right-neighboring edgelet, and a left link to a left-neighboring edgelet; for each edgelet at a position in the two-dimensional array, examining neighboring positions in two phases so as to determine which neighboring positions contain a neighboring edgelet which can be connected to the edgelet at the position, a first phase for identifying a right-neighboring edgelet, and a second phase for identifying a left-neighboring edgelet, each phase including examination of an equal number of different neighboring positions; and for each edgelet, storing from the first phase one of a right link and a null link in a first data slot of the data structure of the edgelet, and storing from the second phase one of a left link and a null link in a second slot of the data structure of the edgelet, thereby forming at least one chain of edgelets.