Scanline algorithms in robot path planning

The problem of finding a path for a mobile robot in two dimensions among stationary obstacles using a free-space graph representation of the robot´s workspace is examined. One problem with solutions of this type has been the time it takes to construct a graph from the image of the workspace. Two solutions are presented which seek to resolve this situation by constructing the graph representation `on the fly´ in a scanline fashion by processing the image one line at a time from top to bottom. Each method consists of three processes: one which breaks the obstacles in the image into pseudo-obstacles, another which analyzes the pseudo-obstacles and locates regions in the free space which represent nodes in the graph, and a third which completes the graph by locating similarities of the free space regions and uses them as edges. The modularity lends itself toward pipelined processing to reach the solution. Discussions are presented and results given of the graph construction process and the paths found on sample images as well as comparative times