![](https://csdnimg.cn/release/download_crawler_static/15638137/bg1.jpg)
Abstract—Aiming at the wide application of constant false
alarm rate (CFAR) algorithm in target detection of synthetic
aperture radar (SAR) image, CFAR algorithm is analyzed and
used for multi-target detection of complex background SAR
images. Firstly, iteration algorithm is used to improve the
automatic censoring detector. Secondly, combine with the priori
knowledge of background to detect the desired targets. Finally,
use decision fusion (or operation) to get multi-target detection
image. Experiments show that the algorithm proposed in the
paper can not only detect multi-targets in complex background,
but also make the detection rate reach more than 80%.
Index Terms—Synthetic aperture radar (SAR), constant false
alarm rate (CFAR), complex background, multi-target
detection.
I. I
NT
RODUCTION
arget
detection is one of the core applications of synthetic
aperture radar (SAR) remote sensing [1], [2]. Because of
its constant false alarm probability and adaptive threshold,
constant false alarm rate (CFAR) detection is one of the most
widely used algorithms for ship detection in SAR images [3],
[4]. A CFAR detector determines a detection threshold by
estimating the local background noise power level from the
references cells and multiplying it by a scaling factor. Several
types of CFAR detector have been suggested in the literature.
The commonly used CFAR detection algorithms include the
cell averaging CFAR (CA-CFAR) [5], greatest of CFAR
(GO-CFAR), smallest of CFAR (SO-CFAR) [6], order
statistic CFAR (OS-CFAR) [7], etc. Each of them has its
advantages, disadvantages, and situations of potential
application. No single detector performs well in all kinds of
scenes. Two-parameter CFAR is the earliest proposed, its
background statistical model adopts Gaussian distribution,
and the detection performance is well in the background of
Man
uscript received March 6th, 2017; revised March 23th, 2017. This
work was supported National Natural Science Foundation of China (No.
61501228), Natural Science Foundation of Jiangsu (No. SBK2014043002),
Aeronautical Science Foundation of China (No. 20152052029)..
Y.Kong Author is with the Electronic and Information Engineering
Department,Nanjing University of Aeronautics and astronautics,
NUAA,China(e-mail:yayako_zy@nuaa.edu.cn).
C.Nie Author is with the Electronic and Information Engineering
Department,Nanjing University of Aeronautics and astronautics,
NUAA,China(e-mail:interstice@163.com).
F.Ge Author is with the Electronic and Information Engineering
Department,Nanjing University of Aeronautics and astronautics,
NUAA,China(e-mail:gefen@nuaa.edu.cn).
S.Xing Author is with the Department of Electronic and Computer
Engineering, University of Calgary, UC, Canada (e-mail:
shiyu.xing@yahoo.ca).
H.Leung Author is with the Department of Electronic and Computer
Engineering, University of Calgary, UC, Canada (e-mail:
Leungh@ucalgry.ca).
un
iform clutter. Later, many scholars have improved the
two-parameter CFAR detector. Salazar proposed CFAR
detector based on beta-prime distribution. Blacknell proposed
CFAR detector based on the relevant Gaussian distribution.
However, these methods have limitations for multi-target
detection in complex background. Yuan et al. proposed a
method based on the stepwise cumulation CA-CFAR
(SCCA-CFAR) detection, which detects the multi-target by
interfering with the target sample point automatic deletion
scheme and has achieved good Detect performance, but very
time consuming. An automatic censoring detector is proposed
for target detection in high-resolution SAR images [8]. It
adopts G0 distribution as the statistical model of clutter. Cui
et al. proposed an iterative CFAR detection for the influence
of other target samples in the local CFAR window [2]. An et
al. improved the detector by adding a new initialization and
clutter suppression method [9], but lacking the background
prior knowledge.
In this paper, the background prior knowledge and iterative
algorithm are used to automatic censoring detector.
Experiments show that it can effectively detect multi-targets
in complex background SAR images. The proposed scheme is
introduced in Section II, experimental results are given in
Section III. Section IV is the conclusion.
II. ITERATIVE
CFA
R
DET
ECTION
The sliding reference window shown in Fig. 1 is used for
CFAR detection. The window is partitioned into three parts.
At the center is the cell under test; in the middle is the guard
area for preventing possible spills of distributed target into the
clutter area; at the outermost part of the window is the clutter
area used for clutter estimation. In practical applications,
when the clutter parameter is estimated, target two is likely to
be mixed into the clutter area. If mixed with a strong target,
the detection area of the weak target is likely to be missed.
Take the Gamma distribution as an example.
1
1
( )
n n
n n
p x x x x
n
(1)
Where n
is the image view and
is
the average energy of the
image.
If
the clutter distribution is Gamma distribution,
is
the
parameter to be estimated. The maximum likelihood
estimation of the clutter power
is
1
1
ˆ
N
i
N
(2)
Where I
i
is the sam
ple in clutter area.
For CA-CFA
R, assuming that the detection area has only
one test pixel, its pixel value is I, if
Multi-target CFAR Detection Based on SAR
Imagery of Complex Background
Yingy
ing Kong, Chunxia Nie, Fen Ge, Shiyu Xing, Henry Leung, Fellow, IEEE
Proceedings of the World Congress on Engineering 2017 Vol I
WCE 2017, July 5-7, 2017, London, U.K.
ISBN: 978-988-14047-4-9
ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online)