Point density reduction in Persistent Scatterer Interferometry

Persistent Scatterer Interferometry (PSI) is widely used to determine ground deformation rates and histories. The data sets processed are increasing in size due to larger areas considered, higher resolution, and higher point densities. Working with lists of several million points and related networks reduces the computational efficiency. In this paper a method to adaptively reduce the size of the point list is presented. Considering the local point density and a point quality measure points are removed such that the density is significantly reduced in areas of very high density while maintaining the available density in areas of lower density. The main PSI processing is then done for the reduced point list. Later on the result obtained for the reduced list is expanded to the full point list. In several cases this methodology improves the processing efficiency significantly.