3-Dimensional Reconstruction on Tagged Packages
via RFID Systems
Yanling Bu, Lei Xie, Jia Liu, Bingbing He, Yinyin Gong and Sanglu Lu
State Key Laboratory for Novel Software Technology, Nanjing University, China
yanlingbu@foxmail.com, lxie@nju.edu.cn, jialiu.cs@gmail.com,
{hebb, yygong}@dislab.nju.edu.cn, sanglu@nju.edu.cn
Abstract—Nowadays, 3D reconstruction has been introduced
in monitoring the package placement in logistic industry-related
applications. Existing 3D reconstruction methods are mainly
based on computer vision or sensor-based approaches, which are
limited by the line-of-sight or battery life constraint. In this paper,
we propose RF-3DScan to perform 3D reconstruction on tagged
packages via passive RFID, by attaching multiple reference tags
onto the surface of the packages. The basic idea is that by
moving the antenna along straight lines within a constrained
2-dimensional space, the antenna obtains the RF-signals of the
reference tags attached on the packages. By extracting the phase
differences to build the angle profile for each tag, RF-3DScan
can compare the angle profiles of the different reference tags and
derive their relative positions, then further determine the package
orientation and stacking for 3D reconstruction. We implement
RF-3DScan and evaluate its performance in real settings. The
experiment results show that the average identification accuracy
of the bottom face is about 92.5%, and the average estimation
error of the rotation angle is about 4.08
◦
.
I. INTRODUCTION
Nowadays, the traditional logistic industry-related appli-
cations, such as warehouse management and logistic trans-
portation, are emerging with brand new requirements. For
example, during the process of warehouse management or
logistic transportation, the packages are usually required to be
placed according to some specified regulations. In particular,
in regard to a single package, if it contains orientation-sensitive
goods, such as chemical reagents or precision instruments,
then it is prohibited from being rollover or upside down;
in regard to multiple packages, they are also required to be
precisely arranged in some specified order, e.g., heavy objects
are placed on the bottom, whereas light objects are placed
on the top, to ensure safety in the transportation. To deal
with the above requirements, the technology of 3-dimensional
(3D) reconstruction has been introduced to tackle these issues
in monitoring the package placement. 3D reconstruction is a
process of capturing the shape and appearance of a single or
multiple real objects. In principle, there are two key aspects
to realize 3D reconstruction for packaged objects: 1) Package
orientation for a single object, it refers to determining the
relative orientation for each package, i.e., figuring out the
bottom/top face, as well as the angles of the other vertical sides
for the specified object in the specified coordinate system. 2)
Package stacking for multiple objects, it refers to determining
the relative stacking situation for multiple packages, i.e.,
performing the relative localization of multiple objects.
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Fig. 1. 3D reconstruction on tagged packages via mobile scanning
Existing 3D reconstruction methods are mainly based on
computer vision or sensor-based approaches. Computer vision-
based approaches leverage the cameras to capture the appear-
ance and build the 3D profiles of objects [1, 2]. They are able
to reconstruct the shape of objects in a vivid approach. The
main disadvantage is the line-of-sight constraint in capturing
images, which leads to blind angles in 3D reconstruction
with only one fixed camera. Sensor-based approaches usually
leverage inertial sensors attached to the items to detect the
orientation variation of the specified items [3, 4]. However,
they suffer from high hardware cost of the sensors, as well
as the limited battery life for the sensors. Fortunately, the
rising use of RFID technology in the logistic industry has
brought brand new opportunities to 3D reconstruction on
packaged objects. In current logistic industry, RFID tags have
been widely used to label the packages with exact logistics
information. In comparison to the above two approaches, the
passive RFID tag is battery-free and very cheap, and the
backscatter-based communication from RFID is not limited
by the line of sight requirement. Most importantly, for most
logistic applications, the RFID systems are already deployed
in the sites to scan and identify the tagged packages.
Therefore, in this paper, we propose RF-3DScan, which
aims to perform 3D reconstruction on packaged objects via
the RFID systems (in Fig. 1). Our idea is based on the
observation that by attaching multiple tags onto the surface
of the packages, we are able to derive the 3D orientation of
each single package and the 3D stacking situation of multiple
packages according to the backscattered RF-signals from these
reference tags. Our approach of RF-3DScan is as follows: We
attach a set of reference tags on the surface of the packages,
then we utilize a single RFID antenna to continuously scan
the tagged packages, while the antenna is moving along