Performance analysis of ghost imaging lidar in
background light environment
CHENJIN DENG,
1,2
LONG PAN,
1,2
CHENGLONG WANG,
1,2
XIN GAO,
1
WENLIN GONG,
1,
* AND SHENSHENG HAN
1
1
Key Laboratory for Quantum Optics and Center for Cold Atom Physics of CAS, Shanghai Institute of Optics and Fine Mechanics,
Chinese Academy of Sciences, Shanghai 201800, China
2
University of Chinese Academy of Sciences, Beijing 100049, China
*Corresponding author: gongwl@siom.ac.cn
Received 8 June 2017; revised 10 July 2017; accepted 10 July 2017; posted 20 July 2017 (Doc. ID 297457); published 21 August 2017
The effect of background light on the imaging quality of three typical ghost imaging (GI) lidar systems (namely
narrow pulsed GI lidar, heterodyne GI lidar, and pulse-compression GI lidar via coherent detection) is inves-
tigated. By computing the signal-to-noise ratio (SNR) of fluctuation-correlation GI, our analytical results, which
are backed up by numerical simulations, demonstrate that pulse-compression GI lidar via coherent detection has
the strongest capacity against background light, whereas the reconstruction quality of narrow pulsed GI lidar is
the most vulnerable to background light. The relation ship between the peak SNR of the reconstruction image and
σ (namely , the signal power to background power ratio) for the three GI lidar systems is also presented, and the
results accord with the curve of SNR- σ .
© 2017 Chinese Laser Press
OCIS codes: (110.0110) Imaging systems; (110.2990) Image formation theory; (110.1758) Computational imaging.
https://doi.org/10.1364/PRJ.5.000431
1. INTRODUCTION
Ghost imaging (GI) is a novel non-scanning imaging method to
obtain a target’s image with a single-pixel bucket detector [1–6].
Due to its capacity for high detection sensitivity, GI has aroused
increasing interest in remote sensing, and a new imaging lidar
system called GI lidar has gradually developed [7–15]. Up to
now, there have been three types of three-dimensional GI
lidars, namely narrow pulsed GI lidar, heterodyne GI lidar,
and pulse-compression GI lidar via coherent detection [12–15].
Due to their distinct mechanisms, their advantages and disad-
vantages are obviously different. For narrow pulsed GI lidar, a
series of high-power laser pulses with independent speckle con-
figurations illuminate onto the target, and the backscattered
intensity is directly received by a time-resolved bucket detector
[7–13]. The structure of pulsed GI lidar is simple, but its
imaging quality is su bject to a low-detection signal-to-noise
ratio (SNR). Heterodyne GI lidar employs a spatiote mporal
modulated light generated by temporal chirped amplitude
modulation (ch irped-AM) and transverse random modulation
[14]. Using a de-chirping method, a high-range resolution can
be obtained even with the use of a long pulse. However, similar
to narrow pulsed GI lidar, heterodyne GI lidar uses a direct
light-detection mechanism, which leads to a shorter detection
distance because the laser’s power is relatively low compared
with narrow pulsed GI lidar. Pulse-compression GI lidar via
coherent detection shares similar spatiotemporal light with
heterodyne GI lidar, but its detection mechanism is based
on coherent detection [15]. Pulse compression gives this lidar
high-range resolution, long detection range, and insensitivity to
stray light. However, in order to ensure heterodyne efficiency,
the laser’s line width is usually very narrow and the numerical
aperture of the receiving system should be ver y small. In
remote-sensing GI lidar detection applications, background
light is inevitable and its intensity may be greater than the
intensity of the signal. Therefore, it would be ver y useful to
clarify the influence of background light on the imaging quality
of GI lidar systems.
In this paper, the performance of the three aforementioned
GI lidar system s is analyzed in a backgroun d light environment.
In Section 2, we theoretically analyze the imaging SNR of
pulsed GI lidar, heterodyne GI lidar, and pulse-compression
GI lidar via coherent detection, when the signal light is
contaminated by background light. Following the analysis,
we give a numerical simulation to demonstrate the performance
of these systems under different levels of background light in
Section 3. Finally, a conclusion is made in Section 4.
2. SYSTEM ANALYSIS
Figure 1 is the schematic of the three different types of GI lidar:
(A) narrow pulsed GI lidar, (B) heterodyne GI lidar, and
(C) pulse-compression GI lidar via coherent detection. In these
lidar systems, modulated light pulses are generated and divided
into reference and test paths by a beam splitter (BS). In the
reference path, the light’s far-field intensity distribution
Research Article
Vol. 5, No. 5 / October 2017 / Photonics Research 431
2327-9125/17/050431-05 Journal © 2017 Chinese Laser Press