Multistatic sonar imaging: comparisons between the matched filtering method and a reconstruction method based on the Kirchhoff approximation
Résumé
In this study, comparisons are made between two imaging techniques in the context of the Multistatic Synthetic Aperture Sonar (SAS): the Matched Filtering algorythm (MFA) and a reconstruction method based on the Kirchhoff Approximation (KA) are presented. The Matched Filtering Algorithm is the classical method used for image formation purposes in synthetic aperture systems. In this method the field diffracted by the target is approached by a “point scatterers” model. One of the first objective of this work is to develop a more complex and more realistic model than the “point scatterers” model. In addition, the aim is to get not only shape and size of target but also some quantitative information about its physical properties. A forward model based on the KA is proposed in the a multistatic context. A reconstruction method based on the KA is established by a 2-D Fourier transform of this forward model. The algorithm obtained is called: “Imaging Reconstruction Algorithm in the Kirchhoff Approximation” (IRAKA). In this paper the IRAKA is compared to the MFA. Images of 2-D targets of circular and elliptic cross-sections are reconstructed with the MFA and with the IRAKA from both numerical data and tank experimental data. Both algorithms are also used to reconstruct images of a 2-D target of circular cross-section in a multistatic forward looking SAS context.