A method using a relaxed adaptive feature extraction algorithm is investigated to interpolate broadband, high-frequency scattering from sparse, undersampled data. First, the adaptive feature extraction is extended to include a frequency-dependent scattering center model in order to better-describe broadband scattering physics from a complex target per the geometrical theory of diffraction. Second, the parameterization of the model is relaxed for more accurate extractions and a sparser model representation using fewer samples. Comparative results are presented for the relaxed versus the non-relaxed adaptive feature extraction algorithm for hypothetical examples and a numerically-solved ogive body of revolution. The relaxed algorithm is more computationally expensive, but results in significantly improved performance. The technique enhances adaptive feature extraction performance for broadband interpolation.
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