Variable density acoustic tomography

The theory and algorithms of diffraction tomography are generalized to the case of acoustic objects whose density and compressibility vary as a function of position. A generalized projection‐slice theorem is presented for objects of this class and filtered backpropagation algorithms are derived that allow separate reconstructions of the objects’ density and compressibility using measurements of the transmitted acoustic field performed at two distinct frequencies. Computer simulations are presented testing the algorithms in the noise‐free case.