Superresolution in ultrasound imaging

Ultrasound techniques for imaging objects significantly smaller than the source wavelength are investigated. The present overview explains two such methods that are being investigated in our laboratory. The first method is designed for detecting scattering using an unfocused ultrasound field created from a continuously-driven source array. The frequency of each element on the array is unique, resulting in a field that is highly variant as a function of both time and position. The scattered signal is then received by a single receiving line and reconstructed. The second method uses a more ldquotraditionalrdquo superresolution reconstruction approach, which recovers spatial frequencies above the spatial bandwidth through analysis of the spatial frequency spectrum. In both cases reconstruction of objects at least an order of magnitude smaller than the signal wavelength can be achieved.