Millimeter-wave imaging using accelerated coherence factor based range migration algorithm

Abstract

For millimeter-wave imaging systems, techniques pertaining to higher image quality seem attractive. Super-resolution (SR) approaches achieve better resolved results without extra system requirements. A computationally efficient SR imaging approach is proposed in this paper. The coherence factor (CF) is invoked and recast into the framework of range migration algorithm (RMA). Different from our previously proposed version (termed CF-RMA), CF is reformulated in the wavenumber domain, and the incoherent power of the reflectivity function is redefined and implemented with one-dimensional (1-D) inverse fast Fourier transform (IFFT) conveniently. As such, the proposed accelerated CF (ACF) is more suitable to be integrated into RMA, achieving faster implementation. As demonstrated in the simulation and experimental results, our addressed ACF based RMA (ACF-RMA) achieves spatial resolution enhancement, and sidelobes and background level suppression with respect to RMA. As indicated by the structural similarity (SSIM) index quantitatively, the image quality of ACF-RMA is on-par with that of CF-RMA. Finally, the computation load of ACF-RMA is estimated. The proposed SR imaging method is demonstrated to be an appropriate candidate for real-time systems.