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In the design of low-frequency transducer arrays for active sonar systems, the acoustic interactions that occur between the transducer elements have received much attention. Because of these interactions, the acoustic loading on each transducer depends on its position in the array, and the radiated acoustic power may vary considerably from one element to(More)
Medical ultrasonography is a powerful and cost-effective diagnostic technique. To date, high-end medical imaging systems are able to efficiently implement real-time image formation techniques that can dramatically improve the diagnostic capabilities of ultrasound. Highly performing and thermally efficient ultrasound probes are then required to successfully(More)
Capacitive micromachined ultrasonic transducers (CMUTs) bring the fabrication technology of standard integrated circuits into the field of ultrasound medical imaging. This unique property, combined with the inherent advantages of CMUTs in terms of increased bandwidth and suitability for new imaging modalities and high frequency applications, have indicated(More)
In modern ultrasound imaging devices, two-dimensional probes and electronic scanning allow volumetric imaging of anatomical structures. When dealing with the design of such complex 3-D ultrasound (US) systems, as the number of transducers and channels dramatically increases, new challenges concerning the integration of electronics and the implementation of(More)
Most of ultrasound medical imaging systems currently on the market implement standard Delay and Sum (DAS) beamforming to form B-mode images. However, image resolution and contrast achievable with DAS are limited by the aperture size and by the operating frequency. For this reason, different beamformers have been presented in the literature that are mainly(More)
High-frequency transducers, up to 35-50 MHz, are widely used in ophthalmic echography to image fine eye structures. Phased-array techniques are not practically applicable at such a high frequency, due to the too small size required for the single transducer element, and mechanical scanning is the only practical alternative. At present, all ophthalmic(More)
The current standard used for the characterization of ultrasonic transducers is the hydrophonic technique, which is able to measure the acoustic pressure profile. This technique allows a quantitative analysis, but is marred by several problems. A scan of the region of interest is a time-consuming operation, especially when measuring a long acoustic beam.(More)
Improving the frame rate is an important aspect in medical ultrasound imaging, particularly in 3D/4D cardiac applications. However, an accurate trade-off between the higher frame rate and image contrast and resolution should be performed. Plane-Wave Imaging (PWI) can potentially achieve frame rates in the order of 10 kHz, as it uses a single unfocused plane(More)
The Delay Multiply and Sum (DMAS) beamforming algorithm was originally conceived for microwave imaging of breast cancer. In a previous work, we demonstrated that, by properly modifying and improving the algorithm processing steps, DMAS can be successfully applied to ultrasound signals for B-mode image formation and that it outperforms standard Delay and Sum(More)