Spatially Variant Apodization for Grating and Sidelobe Suppression in Near-Range MIMO Array Imaging

In this article, a grating and sidelobe suppression method for near-range multiple-input multiple-output (MIMO) array imaging is proposed, which achieves grating and sidelobe suppression by reducing the sidelobes of the transmitting and receiving array. The method first utilizes the generalized matched filtering (GMF) for imaging to obtain the imaging results which are separable along the transmitting and receiving array. Then, an image domain phase compensation term is derived to eliminate the spatially variant characteristic of the wavenumber spectrum, and a spatially variant weighting scheme with the adaptive weighting range is proposed to reduce the sidelobes of the transmitting and receiving array, respectively. The proposed method can effectively suppress the grating and sidelobes while maintaining the width of the mainlobe. Both simulated and experimental data verify its effectiveness.