Developing Real-Time Implementations of Non-Linear Beamformers for Enhanced Optical Ultrasound Imaging

Free-hand optical ultrasound (OpUS) imaging is an emerging ultrasound imaging paradigm that utilises an array of fiber-optic sources and a single fiber-optic detector to achieve video-rate, real-time imaging with a flexible probe that is immune to electromagnetic interference. Due to the use of only a single detector, such probes have limited channel counts, resulting in significant imaging artefacts and limited contrast when imaging is performed with a conventional Delay-and-Sum (DAS) beamformer. Non-linear beamforming can help improve the imaging quality by exploiting cross-channel coherence across the aperture, at the expense of significantly increased computational complexity. In this work, GPU implementations of different non-linear beamformers were implemented and tailored specifically to OpUS array devices and tested on both simulated and experimental data.