Comparison of digital beamforming algorithms for 3-D terahertz imaging with sparse multistatic line arrays

Abstract

Abstract. In this contribution we compare the backprojection algorithm with our recently developed modified range migration algorithm for 3-D terahertz imaging using sparse multistatic line arrays. A 2-D planar sampling scheme is generated using the array's aperture in combination with an orthogonal synthetic aperture obtained through linear movement of the object under test. A stepped frequency continuous wave signal modulation is used for range focusing.Comparisons of the focusing quality show that results using the modified range migration algorithm reflect these of the back-projection algorithm except for some degradation along the array's axis due to the operation in the array's near-field. Nevertheless the highest computational efficiency is obtained from the modified range migration algorithm, which is better than the numerically optimized version of the back-projection algorithm. Measurements have been performed by using an imaging system operating in the W frequency band to verify the theoretical results.

Quantum range-migration-algorithm for synthetic aperture radar applications

“…Among these reconstruction algorithms the range-migration algorithm (RMA, see Fig. 1 B for a scheme) has the lowest complexity—especially when being implemented using fast Fourier transforms (FFTs) 6 , 7 . Still, the complexity of the 3D RMA scales with approximately 2 N 2 N f log 2 ( N ) + N 2 N f + N 2 N f M interp + N 2 N f log 2 ( N 2 N f ), corresponding to N f 2D-FFTs, phase compensation, Stolt interpolation ( M interp being the complexity of the interpolation kernel) and the last term corresponding to the 3D inverse FFT 6 .…”