 A similar approach, using voltage-current histograms and a simplified statistical measure of distance between signature images has been evaluated for tungsten inert gas (TIG) welding by researchers from Osaka University.SIP provides the basis for the "WeldPrint" system, which consists of a front-end interface and software based on the SIP engine and relies on electrical signals alone.It is designed to be non-intrusive and sufficiently robust to withstand harsh industrial welding environments.