Multiple scattering can enlarge the angular diversity reaching a receiver array. Reversing the paths then makes the array act like a larger aperture, improving the focus in appropriate regimes of wave propagation in a random medium.
For a linear operator mapping transmitted signals to recorded signals, the positive operator describes adjoint back-propagation after recording. In a reciprocal array, physical time reversal acoustics implements this operation up to a final complex conjugation and the chosen signal conventions.
The DORT method uses eigenvectors of a time reversal operator to focus on individual point scatterers. A separate nonzero eigenvalue corresponds to each scatterer in the ideal weak-scattering, well-resolved limit; coherent overlap and multiple scattering can change this correspondence.
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Acoustics is the branch of physics that deals with the study of sound, including its production, transmission, and effects. It encompasses various phenomena related to sound waves, such as their generation, propagation, and interaction with different materials and environments. Key areas of acoustics include: 1. **Physical Acoustics**: This area focuses on the fundamental principles of sound waves, including their frequency, wavelength, amplitude, and speed.