Subband compound with fundamental wave and harmonics in focus wave beamforming

Abstract

Abstract The use of harmonics offers high resolution and low artifact imaging. However, the image intensity depends on the depth of field and is significantly weaker than the fundamental echo. The simultaneous use with the fundamental echo is therefore desirable. However, the frequency bands corresponding to the fundamental and harmonics are different, and the difference in value between their amplitudes is large. Imaging them simultaneously is difficult. Therefore, we propose a method that employs a single short-period transmission of a low-frequency pulse signal so that the fundamental and the harmonic meet. Then we use the subband compound method which treats the fundamental and harmonic bands as a single frequency band. Several regularized subbands of different frequencies are subsequently extracted from the entire frequency band. In effect, this method uses the phase information of the frequency band and improves the spatial resolution and signal-to-noise ratio through sub-band amplitude modulation while suppressing artifacts.