An innovative approach towards detection and exclusion of overlapped regions in guard zone computation

The guard zone computation problem is of utmost importance in the domain of VLSI physical design automation as one of the major purposes is to find an optimized way to place a set of two-dimensional blocks on a chip floor. Beyond this, it has huge significance in the field of robotic motion planning, Geographical information system, automatic monitoring of metal cutting tools and design of any embedded systems. In VLSI layout design, the circuit components (or the functional units / modules or groups / blocks of different sub-circuits) that may be viewed as a set of polygonal regions on a two-dimensional plane, are not supposed to be placed much closer to each other in order to avoid electrical (parasitic) effects among them. Each (group of) circuit component(s) C_i is associated with a parameter δ_i such that a minimum clearance zone of width δ_i is to be maintained around C_i. If the guard zonal regions overlap, we have to remove the overlapped regions in order to compute the resultant outer guard zone (sometimes inner guard zones are also an issue to be considered). The location of guard zone (of specified width) for a simple polygon is a very important problem for resizing a (group of) circuit component. In this paper, we have developed an algorithm to compute the guard zone of a simple polygon as well as to exclude the overlapped regions among the guard zonal segments (if any) in O(nlogn) time, where n is the number of vertices of the given simple polygon.