Improve the resolution of Temporal Averaging Minimum Variance by Sign Coherence Factor: application in photoacoustic imaging

Photoacoustic (PA) imaging combining the advantages of high resolution of ultrasound imaging and high contrast of optical imaging provides images with good quality. PA imaging often suffers from disadvantages such as clutter noises and decreased signal-to-noise ratio at higher depths. In order to reconstruct an image, Delay-and-Sum (DAS) beamformer is commonly used due to its simplicity and higher robustness compared to other beamformers. However, this beam former's resolution and side lobes rejection are not adequate; in order to address this predicament adaptive beamformer can be used. We used Temporal Averaging Minimum Variance (TAMV) beamformer, which leads to high resolution in this work. Nevertheless, this beamformer could not deter sidelobes. Therefore, Sign Coherence Factor (SCF) was combined with the TAMV beamformer to boost resolution and reject sidelobes.