Ultrasonic elastography optimization algorithm based on coded excitation and spatial compounding

Abstract

Traditional elasticity imaging systems use short pulses with low sound power, causing the signal to be attenuated severely in deep zones. On the basis of the coded excitation and spatial composition theorems, an ultrasonic elastography optimization algorithm is proposed in this paper. It takes advantage of coded excitation and spatial compounding such as high peak power and average sound power, suppresses speckle noise, and improves the imaging quality effectively. Specifically, a coded excitation system encodes the long pulses when transmitting, and then decodes the long pulses into short pulses upon receiving. This increases the average sound power of the beam without sacrificing the spatial resolution. A imaging system based on coded excitation can therefore achieve a good signal-to-noise ratio (SNR_e) and contrast-to-noise ratio (CNR_e) in deep zones below the detection surface. The proposed algorithm combines coded excitation with a filter-group based spatial compounding algorithm at the receiving terminal. Finally, experimental results show that the proposed algorithm yields a higher SNR_e and CNR_e than using chirp coded excitation or spatial compounding alone.