| Background, Motivation and Objective The classical synthetic aperture technique, with only one channel to emit/receive, where the elements of the phased array are sequentially activated, is very popular because it allows decreasing the complexity and the cost of ultrasound imaging systems. Furthermore it has other advantages such as: it is possible to focus the main beam dynamically in emission/reception; the lateral resolution is improved with respect to the original phased array; and also, if the image is composed by fewer lines than elements, it is able to generate images faster than the phase array. However, the contrast achieved with this method is significantly lower than the one obtained with the phase array. This is because the SAFT coarray (sometimes called “effective aperture”) resulting from the addition of all the convolutions between the emission and reception sequences, produces an element distribution that doubles the inter-element spacing, thus introducing grating lobes in the beam pattern. This work presents a new SAFT configuration that uses one element in emission and two elements in reception, which suppresses the grating lobes maintaining the advantages of the classical SAFT. Here, we present this SAFT configuration (that we call Two-elements SAFT or T-SAFT) and its electronic architecture which uses the coarray for generating the images. Statement of Contribution/Methods The T-SAFT strategy uses one element in emission and two elements in reception: the one emitting and its adjacent. With this configuration each received signal corresponds with every virtual element of the coarray, where the inter-element distance is now maintained as in the original phased array. The received signals, organized in the coarray structure, with no redundancy, can be processed in one-way using the virtual elements of the coarray. This is because the one way dynamic beamforming of the coarray is equivalent to the two-ways dynamic beamforming of the synthetic aperture. The electronic architecture for dynamic focusing in emission and reception is based on the coarray, what allows a simplification of the beamforming process. Results Simulations models and experimental tests have been developed to study the T-SAFT properties. A good agreement between experimentation and simulation confirms the goodness of the proposed method. Also, several apodization models have been used to improve the image quality and experimental. An electronic architecture based on the coarray is also proposed. Discussion and Conclusions The proposed T-SAFT configuration, with low hardware requirements, is able to maintain the principal advantages of the classical SAFT avoiding its main disadvantage: grating lobes formation. If two parallel channels are used in reception, the image frame rate is tied to the number of emitting elements in the original array, similar to the classical SAFT mode. |