Piezo-polymer transducers for ultrasonic imaging in air

Airborne polyvinylidenefluoride transducers have been designed for robotic applications in air. Characteristics of transducer prototypes are: working frequencies from 61 kHz to 86 kHz, quality factor Q from 4 to 6, and two-way insertion loss of about 90 dB. The small dimension, the lightness, and the low-cost fabrication technology allow the development of arrays or matrices for ultrasonic imaging systems in air. In this work two different image reconstruction algorithms are proposed: the first carries out a combined spectral and aperture synthesis for detecting isolated scatterers with a spatial resolution of about 2 mm; the second is based on an accurate ranging algorithm with sub-millimeter resolution at distances up to 50 cm. Finally, this work's application to the reconstruction of three-dimensional object profiles is discussed.