Improving the quality of photoacoustic images using the short-lag spatial coherence imaging technique

Abstract

Clutter noise is an important challenge in photocoustic (PA) and ultrasound (US) imaging as they degrade the image quality. In this paper, the short-lag spatial coherence (SLSC) imaging technique is used to reduce clutter and side lobes in PA images. In this technique, images are obtained through the spatial coherence of PA signals at small spatial distances across the transducer aperture. The performance of this technique in improving image quality and detecting point targets is compared with a conventional delay-and-sum (DAS) beamforming technique. A superior contrast, contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) are observed when SLSC imaging is employed. Point spread function of point targets shows an improved spatial resolution and reduced side lobes when compared with DAS beamforming. Also shown is the impact of increasing the number of frames on which SLSC is applied. The results show that contrast, CNR, and SNR are improved with increasing number of frames.