RESUMEN
In a 2021 paper, we delved into the details of delay-sum beamforming (DAS) in high-frame-rate ultrasound for medical imaging [1]. We also proposed a simple and fast method of determining an f-number, which is based on the directivity of the transducer elements. In their comment, Martin F. Schiffner and Georg Schmitz argue that we mistakenly link image quality enhancement to the reduction of measurement noise. They disapprove our proposed f-number, claiming it deteriorates the signal-to-noise ratio (SNR). Based on their previous work [2], they also highlight that the f-number should be derived from the grating lobe angles. In this reply, we explain their error in the SNR argument. We also illustrate the potential drawbacks of exclusively relying on grating lobes to establish an f-number with a DAS, suggesting that alternative approaches might be worthy of consideration.
RESUMEN
It is shown herein that Perrot et al., who reviewed delay-and-sum beamforming for ultrafast ultrasound imaging in [Ultrasonics 111 (2021) 106309], misinterpreted the purpose of dynamic receive apertures. Such apertures widen with the focal length as a function of a given f-number and improve the image quality by suppressing grating lobes. Perrot et al., however, attributed erroneously the image quality improvement to suppression of measurement noise and, in doing so, proposed a suboptimal method to determine an f-number.