Omega-K beamforming: Practical ramifications of alternative formulations

The Omega-K algorithm is widely used for creating imagery from synthetic aperture sonar and radar data. In early literature related to Omega-K beamforming, two alternative forms of the algorithm exist: one in which a critical matched-filtering stage is applied before Stolt-mapping and one in which it is applied after. The former was adopted as the standard approach in both fields. In the present study, it is demonstrated that applying the matched-filter prior to Stolt-mapping has the potential to alias acoustic energy associated with wide aperture angles, causing artifacts in imagery, whereas the alternative formulation avoids these artifacts.