  Photoacoustic imaging (PAI) is a powerful imaging modality that relies on the
PA effect. PAI works on the principle of electromagnetic energy absorption by
the exogenous contrast agents and/or endogenous molecules present in the
biological tissue, consequently generating ultrasound waves. PAI combines a
high optical contrast with a high acoustic spatiotemporal resolution, allowing
the non-invasive visualization of absorbers at deep structures. However, due to
the optical diffusion and ultrasound attenuation in heterogeneous turbid
biological tissue, the quality of the PA images is deteriorated. Therefore,
signal and image processing techniques are imperative in PAI to provide high
quality images with detailed structural and functional information in deep
tissues. Here, we review various signal and image processing techniques that
have been developed/implemented in PAI. Our goal is to highlight the importance
of image computing in photoacoustic imaging.
