Weighted non-linear beamformers for low cost 2-element receive ultrasound imaging system

Optimally-weighted non-linear beamformer for conventional focused beam ultrasound imaging systems

“…In F-DwMAS, a set of window coefficients raised to the power of 'r' are multiplied to the aperture data, where 'r' can be used as a tuning parameter to control image quality. Whereas, in F-DewMAS, the combinatorial combinations of the window coefficients obtained after the multiplication stage are raised to the power of 'Euclidian distance' 26 . In general, these operations can be mathematically represented as in Eq.…”

“…x(i,j) is the weighted combinatorially coupled data, y(i,j) preserves the sign and finds the square root x(i,j) and n is the number of transducer elements in receive aperture. Further detailed explanation of F-DwMAS and F-DewMAS beamforming methods can be found in reference Vayyeti and Thittai 26 .…”

Pixel-based approach to delay multiply and sum beamforming in combination with Wiener filter for improving ultrasound image quality

“…The F-DMAS also imposes a high computational load due to the square root and multiplications operations in the image generation [16], but there are some fast implementations proposed in [17,18] to address the issue. The method has been further improved for better performance in subsequent studies, such as double-stage F-DMAS [19], subarray F-DMAS [20], signed DMAS [21,22], baseband DMAS [23], and weighted F-DMAS [24,25].…”

Multi-mode laser-ultrasound imaging using Time-domain Synthetic Aperture Focusing Technique (T-SAFT)

“…Many imaging algorithms that are suitable for UT have been developed for defect imaging. One algorithm called the Synthetic Aperture Focusing Technique (SAFT), which originated from radar detection, has proven to be an effective tool for defect imaging using both ultrasonic [21] and laser ultrasonic [22] signals. The frequency domain SAFT (F-SAFT) utilises concepts such as the angular spectrum method (ASM) and phase shift migration (PSM) [23] , whereas in the time domain SAFT, delay and sum (DAS) [24] based on geometric relations is employed.…”