To improve the quality of focused ultrasound images, in the last decade several beamforming algorithms have been proposed as an alternative to the common Delay-And-Sum (DAS), as for example adaptive or non-linear beamformers, which achieve improved imaging performance at the expense of an increased computational load. In this paper, we propose a computationally efficient algorithm based on nonlinear operations which consists in applying DAS to the p-th root of the raw echo signals, followed by p-powering and band-pass filtering. This simulation study demonstrates that the method is able to achieve a great side-lobe rejection coupled with a Contrast Ratio enhancement. However, due to nonlinear operations, the algorithm presents two restrictions: a decrease of Contrast-to-Noise-Ratio and a previous signal oversampling that may be required to avoid aliasing of artificial harmonics induced by non-linear operations.
Polichetti, M., Varray, F., Matrone, G., Savoia, A.S., Bera, J., Cachard, C., et al. (2017). A computationally efficient nonlinear beamformer based on p-th root signal compression for enhanced ultrasound B-mode imaging. In IEEE International Ultrasonics Symposium, IUS (pp.1-4). IEEE Computer Society [10.1109/ULTSYM.2017.8091710].