Novel Ultrasound Imaging Techniques

Ultrasound Imaging is widely used in biomedical and industrial applications, due to its non-invasive, non-destructive and non-ionizing nature. In the last 20 years, Ultrasound imaging has been continuously growing in both of these fields, since it has benefited from advances in electronic technologies and in signal processing methods. For industrial applications, a wide variety of instruments, based on ultrasound, have been designed to measure the properties and composition of materials and products. In particular, monitoring all of the steps of a production chain is crucial for process optimization and product quality in industries. In the medical area, ultrasound systems are widely used to investigate the tissue, by 2D morphological imaging, and the blood movement, by Doppler analysis. The large use of ultrasound equipment has further increased the research and the development activity of new investigation methods. Consequently, “open” systems capable of satisfying the research needs are in great demand. The activity of this PhD was focused on the design of new electronic architectures and systems capable of addressing some of the emerging needs in medical and industrial fields. In several industrial fields the products are checked by taking samples from the production chain, which are lately analyzed in specialized laboratories by using manual, expensive and time consuming operations. Systems capable of in-line and on-site monitoring products and materials would be of high value. For these reasons, we developed an ultrasound system for monitoring the properties of the fluids or suspensions flowing in pipes and another system to assess the concrete strength during the hydration process. The first one is a system with a wide range of applications, since a lot of products as food, medicines and cosmetics are in a fluid or suspension state during the production. It is a pulse wave system that measures the velocity profile of the fluids flowing in a pipe and uses the relation between the velocity profile and the fluid rheological properties to evaluate the quality of the products and keep the production chain under control. The second system evaluates the concrete strength, a parameter of paramount importance to guarantee durable and safe constructions. It is a pulse wave system that exploits a reflectometry technique to monitor the concrete strength evolution during the hardening process by analyzing the reflected signal at interface concrete-Plexiglas. In medical applications, High Frame Rate (HFR) imaging methods based on the transmission of defocused, plane-wave (PW) or multi-focused beams rather than single-focused beams, are increasingly popular. These methods lead to unprecedented performance that enables the reconstruction of 2D vector maps of the blood velocity distribution, or 3D investigations with improved resolution, but they are unfortunately very demanding in term of processing power. Therefore, the design and development of novel HFR methods and systems capable to efficiently implement the HFR imaging methods, is a crucial challenge. Toward this goal the Micro Systems Design Laboratory (MSD Lab) of the University of Florence developed a novel research scanner called ULtrasound Advanced Open Platform 256 (ULA-OP 256). ULA-OP 256 can independently manage up to 256 transmit/receive (TX-RX) channels. It has high computational power in a small size, compatible with mobility. The system supports a wide range of transmission/receiving strategies, processes data in real time, stores data for post-processing, and can be connected to matrix probes. In particular, the platform implements an advanced beamformer architecture, named Multi-Line Parallel Beamformer (MLPBF). MLPBF exploits a combination of parallel and serial processing strategies that make HFR imaging possible.