Frequency-Domain Imaging Algorithm for Single-Input–Multiple-Output Array

In this letter, a novel frequency-domain imaging method is proposed for a single-input-multiple-output array, which avoids the frequency-domain interpolation. This method transforms the measurements into the wavenumber domain for compensation. The spectrum data at each frequency are proved to be the Fourier transform of the phase-modulated reflectivity function; therefore, a subimage at a specific frequency can be produced by inverse fast Fourier transform and phase demodulation. The final image is obtained by coherent accumulation of all subimages. This method does not take the plane wave approximation and can be applied in short-range imaging scenes. It has the same imaging accuracy as the backprojection algorithm but greatly reduces the computational load. Both two- and three-dimensional imaging experiments verify its performance.