Passive identification of acoustic propagation media with viscous damping

This paper concerns passive identification of visco-acoustic propagation media through a Green correlation approach. The Green correlation is introduced as the cross-correlation of an acoustic field generated by a white noise exciting the medium. We show that it allows to retrieve the first times of arrival, direct path and first echoes, between two sensors. This approach is experimentally validated and compared to the classical method which consists in retrieving the Green function from the Green correlation through a Ward identity. We show that this latter approach appears to be inaccurate and above all unnecessary in the visco-acoustic case.