A Hierarchical Domain Constraint Enhanced VBIM for Multi-Scale Contrast Objects Reconstruction

A robust hierarchical domain constraint (HDC) strategy is proposed to enhance the VBIM for the multiscale contrast objects reconstruction in this paper. During the iterations of VBIM-HDC, with the classification of background and scatterers cells, the parameters of the background cells are set as the same as the actual background and removed from the inversion. The major work of the VBIM-HDC is to divide the inversion process into several stages, and the classification of cells is evaluated separately at each stage, making the classification reversible. And the HDC can effectively classify the inversion domain of low-contrast objects without negligence in the multiscale contrast objects case, as well as the continuously varying inhomogeneous objects' low-contrast parts. Another advantage of HDC is the threshold determining the classification of cells can be flexibly chosen. This robust constraint of the inversion domain compresses the solution space so that the ill-posedness of the inverse problem is mitigated, and better accuracy thus is achieved. Numerical results validate the accuracy, and robustness of the proposed VBIM-HDC.