Synthetic aperture imaging for small scale systems

摘要

Multi-element synthetic aperture imaging methods suitable fornapplications with severe cost and size limitations are explored. Arraynapertures are synthesized using an active multi-element receivensubaperture and a multi-element transmit subaperture defocused tonemulate a single-element spatial response with high acoustic power. Echonsignals are recorded independently by individual elements of the receivensubaperture. Each method uses different spatial frequencies andnacquisition strategies for imaging, and therefore different sets ofnactive transmit/receive element combinations. Following acquisition,nimage points are reconstructed using the complete data set with fullndynamic focus on both transmit and receive. Various factors affectingnimage quality have been evaluated and compared to conventional imagersnthrough measurements with a 3.5 MHz, 128-element transducer array onndifferent gel phantoms. Multielement synthetic aperture methods achievenhigher electronic signal to noise ratio and better contrast resolutionnthan conventional synthetic aperture techniques, approachingnconventional phased array performance