Input image data define an input image set that shows a node-link structure, such as a directed graph, an undirected graph, a tree, a flow chart, a circuit diagram, or a state-transition diagram. The input image set can include one image showing the node-link structure or two images, one showing graphical...http://www.google.com/patents/US5522022?utm_source=gb-gplus-sharePatent US5522022 - Analyzing an image showing a node-link structure
