A Novel Multi-Angle Spatial Compounding Methodology Towards High-Resolution PMUT-Based Imaging

This work proposes an innovative multi-angle image compounding scheme using a Lead Zirconate Titanate (PZT) piezoelectric Micromachined Ultrasonic Transducer (PMUT) array towards clutter attenuation and speckle artifact suppression. Two 3× 3 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> dies of an 18-channel 1D-array PMUT, whose resonant frequency is 6.5 MHz, were employed for this demonstration. The proposed spatial compounding methodology is based on the aggregation of intermediate images from emitting plane wave at various directions (i.e., reconstructed at different angles) to enhance image quality by steering the beam of the phased array. In addition, a novel algorithm for crosstalk suppression is also proposed here based on Sliding Window Autocorrelation. The proposed signal processing pipeline is validated experimentally demonstrating an impressive performance with significant SNR gains of up to 20dB and highly accurate reflector localization considering a 3 mm-diameter reflector as close as 4 mm to the PMUT array. The impressive experimental results highlight the suitability of the proposed compounding methodology for medical imaging and industrial applications, e.g., NDT and structural health monitoring, underwater acoustics and sonar imaging.