Quantitative comparison of frequency-domain and delay-and-sum optoacoustic image reconstruction including the effect of coherence factor weighting

Florentin Spadin; Michael Jaeger; Robert Nuster; Pavel Subochev; Martin Frenz

doi:10.1016/j.pacs.2019.100149

Quantitative comparison of frequency-domain and delay-and-sum optoacoustic image reconstruction including the effect of coherence factor weighting

Photoacoustics. 2019 Dec 3:17:100149. doi: 10.1016/j.pacs.2019.100149. eCollection 2020 Mar.

Authors

Florentin Spadin¹, Michael Jaeger¹, Robert Nuster², Pavel Subochev³, Martin Frenz¹

Affiliations

¹ Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
² Institute of Physics, Karl-Franzens-University Graz, Austria.
³ Institute of Applied Physics RAS, Nizhny Novgorod, Russia.

Abstract

Image reconstruction in optoacoustic imaging is often based on a delay-and-sum (DAS) or a frequency domain (FD) algorithm. In this study, we performed a comprehensive comparison of these two algorithms together with coherence factor (CF) weighting using phantom and in-vivo mouse data obtained with optoacoustic microscopy. For this purpose we developed an FD based definition of the CF. Our results reveal the equivalence of DAS and FD, with and without CF weighting, in terms of spatial resolution and contrast-to-noise ratio (CNR) but highlight the clear advantage of FD in terms of computational cost, making it preferable for 3D reconstruction or real-time applications. An important additional result of this research is that, contradictory to previous studies, CF weighting does not lead to any improvement in lateral resolution.

Keywords: In-vivo; Lateral resolution; Optoacoustic microscopy; Photoacoustic; Synthetic aperture focusing technique.