Instrumentation & Measurement Magazine 24-4 - 73

If the lifted distance of the
wheels is excessively large,
it is assumed that the truck
has been lifted. CLPS will
stop lifting and transfer to
manual confirmation to
prevent accidents.
Advantages of
VBM
Fig. 15. Container unloading operation and lifting accident. (a) Normal lifting; (b) Lifting accident.
Fig. 16. TLPS equipment installation location. (a) Installation of the system; (b) The detection range of VBM system.
15a). In a complex operation environment, if the container is
lifted without completely unlocking all of the locks, the truck
frame will also be lifted. This is known as a truck lifting accident
(Fig. 15b). A truck lifting prevention system (TLPS) based
on VBM can help prevent this type of accident.
TLPS installs cameras and laser scanners on the side of the
truck near the RMG to detect unloading accidents. As illustrated
in Fig. 16, four cameras are installed to ensure that the
entire container truck can be detected.
After starting the unloading operation, the system will locate
and record the wheel position of the container truck (green
box in Fig. 17). During the entire process, the system will record
the latest wheel position in real time (red box in Fig. 17).
These automated systems
use VBM to recognize and
measure targets and obtain
information. If the automation
equipment is the
hand of the operating system,
the VBM system is
the eye. The automation of
complex operations must
be supported by accurate
operating parameters information
(such as the
object's position and characteristics).
By comparison,
the previous technologies
were not able to acquire
such information, being
characterized by a reduced
degree of automation. A higher degree of automation needs
automated equipment that have a higher ability to obtain operating
parameters. VBM equipment has solved this problem
by obtaining information from image data. Vision-based characteristics
make VBM systems easy to automate and control
remotely which significantly improves the degree of automation
of ACT equipment.
Challenges and Development
Directions
Challenges
The development of VBM in recognition algorithms is relatively
mature, and the challenges it faces are essentially from
the application environment. There are several restrictions regarding
the design and installation of equipment in practical
applications, and various variables (weather, the change of
tasks) in complex industrial processes can interfere with the
vision system. These difficulties can be summarized in the following
four points.
Fig. 17. Truck lifting detection.
June 2021
Challenges Caused by Complex Working
Environment
Container terminals are always operating in harsh conditions
characterized by high humidity (RH > 70%) and high dust levels
(e.g., in the Shanghai Port in China is characterized PM2.5 > 74.4
μg/m3 [14]) that affect the quality of images and make it difficult
to extract specific features. This in turn affects the measurement
IEEE Instrumentation & Measurement Magazine
73

Instrumentation & Measurement Magazine 24-4

Table of Contents for the Digital Edition of Instrumentation & Measurement Magazine 24-4