Research Article
Cylindrical Three-Dimensional Millimeter-Wave Imaging via
Compressive Sensing
Guoqiang Zhao, Shiyong Li, Bailing Ren, Qingwei Qiu, and Houjun Sun
Beijing Key Laboratory of Millimeter Wave and Terahertz Technology, Beijing Institute of Technology, Beijing 100081, China
Correspondence should be addressed to Shiyong Li; lisy @bit.edu.cn
Received December ; Revised July ; Accepted July
Academic Editor: Ali Yapar
Copyright © Guoqiang Zhao et al. is is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Millimeter-wave (MMW) imaging techniques have been used for the detection of concealed weapons and contraband carried by
personnel. However, the future application of the new technology may be limited by its large number of antennas. In order to
reduce the complexity of the hardware, a novel MMW imaging method based on compressive sensing (CS) is proposed in this
paper. e MMW images can be reconstructed from the signicantly undersampled backscattered data via the CS approach. us
the number of antennas and the cost of system can be further reduced than those based on the traditional imaging methods that
obey the Nyquist sampling theorem. e eectiveness of the proposed method is validated by numerical simulations as well as by
real measured data of objects.
1. Introduction
Millimeter-wave (MMW) imaging techniques have been
applied for the detection of concealed weapons and con-
traband carried by personnel at airports and other secure
locations [–]. Millimeter waves can penetrate common
clothingbarrierstoformanimageofapersonaswellas
any concealed items with dierent reectivity or emissivity.
Also, millimeter waves are nonionizing and, therefore, pose
no known health hazard at moderate power levels, not like
X-ray systems.
However, a large number of antennas and switches (maybe
from hundreds to ten thousands) are needed to construct
one- or two-dimensional (D or D) array to obtain three-
dimensional (D) images, which increases the cost of the
imaging system and then limits its wide application. In order
to reduce the complexity and cost of the system, we propose
a compressive sensing- (CS-) based method for D MMW
imaging. e area of CS was initiated in by Cand
`
es et
al. [] and by Donoho [].
CS has been widely explored in the domain of radar
imaging [–], in which the image was usually converted
into a vector. And the D optimization algorithm was used
to recover the image. However, if we convert the D image
into a vector, a huge sensing matrix will be introduced. en
the computational complexity will be largely increased. In
this paper, we introduce an operator as the sensing matrix to
represent the traditional imaging process based on wavenum-
ber domain algorithm (WDA) []. us, large-scale matrix
computations are avoided. e image resolution of the WDA
is determined by signal bandwidth, signal frequency, and the
length of synthetic aperture. And the resolution of the CS-
based imaging algorithm is determined mainly by the signal-
to-noise ratio and the matching degree of signal model to the
requirements of CS, such as the restricted isometry property
(RIP). e simulation and experiment results show that the
CS-based method oers a much more accurate image than
the traditional WDA just using a small subset of the full
samples.
e rest of the paper is organized as follows. In Section ,
theCSimagingmethodbasedonthetraditionalWDAis
introduced. e results demonstrating the eciency and
accuracy of the method are shown in Section . Section
summarizes the conclusions.
Hindawi Publishing Corporation
International Journal of Antennas and Propagation
Volume 2015, Article ID 218751, 6 pages
http://dx.doi.org/10.1155/2015/218751