Novel Efficient 3D Short-Range Imaging Algorithms for a Scanning 1D-MIMO Array

Abstract

Recently, millimeter-wave (MMW) 3D holography techniques employing a scanning 1D multiple input multiple output (MIMO) array have shown several superiorities for short-range applications than traditional single input single output (SISO) ones. However, current imaging algorithms for this emerging regime are not satisfied, either too slow as a back projection (BP) manner is used or of poor quality since several steps of approximations are introduced. In this paper, two fast fully-focused imaging algorithms are developed towards fixing these drawbacks. Both algorithms are based on the assumption that the receivers are evenly distributed. The first algorithm further hypothesizes that the transmitters are also evenly located, while the second algorithm needs looser restrictions that the transmitters can be arbitrarily positioned. The frequency domain expressions of the modified Kirchhoff method are also derived and used to promote the precision of the proposed algorithms. In addition, several implementation issues including resolution, sampling criteria and computational complexity are discussed. Finally, both simulation and experimental results validate the effectiveness of the proposed methods on reconstruction quality and computational efficiency.

Near-Field 3D SAR Imaging Using a Scanning Linear MIMO Array With Arbitrary Topologies

“…where the approximate equation in the last line is obtained by the spherical wave decomposition theory [13]; the synthetic wavenumber components k x , k y are given by…”

“…From Table 1, noting that the computational complexities of NUFFT and FFT are of the same order, we can deduce that the computational complexity of the proposed MIMO-SAR-NUFFT is O N 4 log 2 N , while that of BPA is O N 6 [13]. Alternatively, even if the FT x t [•] and FT x r [•] are implemented directly using Eq.…”

“…In the last decade, multi-input-multi-output (MIMO) techniques started to be widely adopted in near-field 3D SAR imaging [11], [12]. Recently, MIMO-SAR imaging technology is drawing more and more attention as it outperforms previous SISO-SAR imaging systems in several aspects such as higher array utilization efficiency, faster data acquisition speed and better imaging quality [13].…”

“…However, the focusing quality is interrelated with the topology of the MIMO array, which means this imaging algorithm cannot be used for more general array designs. In [13], [17], efficient frequency domain imaging algorithms for a scanning linear MIMO array were proposed, which greatly expedite its progress towards practical applications.…”

Phase Shift Migration With SIMO Superposition for MIMO-Sidelooking Imaging at Terahertz Band

“…Theoretically, to obtain the accurate MIMO imaging results using SIMO superposition, it is required that any aliasing of the target should not arise in the imaging results of each SIMO sub-array. The analysis of the azimuth performance of the SIMO aperture is actually similar to a one-way aperture [33]. Defining that the distance between the target and the center of the receiving array is R, the length of the target along the range is r L , and the length of the target along azimuth is a L , the frequency sampling interval and the spatial sampling interval of the receiving array must satisfy the Nyquist criterion are given by…”