Ultrasonic System for 3D Object Profile Reconstruction in Air

Abstract

Ultrasounds have been widely used in medical and NDT fields but recently they have gained importance also in industrial applications. For these applications the development of new type of low cost airborne ultrasonic transducers leads to consider the ultrasonic instrumentation as a valuable alternative to both optical and mechanical systems. This work investigates the feasibility of an ultrasonic 3D scanner in air based on ferroelectric polymer (PVDF) transducers. A laboratory system has been developed to extract 3D profiles of wood shoe models. The characteristics of accuracy, quickness and absence of mechanical movements make the developed system suitable for just in time fabrication. Common systems are based on 3D pantographs which suffer of low speed due to the mechanical movements and frequent maintenance due to the contact of the measuring head with the wooden model. On the other side advanced systems exploit optical techniques but they result expensive, bulky and sensitive to illumination, dust and dirty.