Mobile Laser Scanning and Imagery (MLSI) System
The MLSI System
Mobile Laser Scanning and Imagery is a surveying technology applying 3D laser scanning from a moving vehicle. The MLSI System minimises disturbance to road traffic by eliminating the need of road closure. The system integrates multiple sensors, including an Inertial Navigation System (INS) for positioning, a high resolution camera system for capturing panoramic street views and road surface images, and a laser scanner capable of measuring up to 2 million point every second for ground features in 3D space.
Video: Mobile Laser Scanning and Imagery (MLSI) System
Showcase Video of Mobile Laser Scanning and Imagery (MLSI) System Application in TV program "Science in Public Service (SIPS) 科學為民"
To celebrate the 15th anniversary of the SIPS Campaign, HyD has participated in the production of a documentary television programme to showcase the application of MLSI system in planning, construction and maintenance of road infrastructure.
Ms Ada CHAN , Land Surveyor, explained the survey applications and advantages of the MLSI system
Mr SZE Wing-sum , Survey Officer (Eng), demonstrated the operation of the system.
The television programme was broadcasted on Radio Television Hong Kong (RTHK) Channel 31 on 9 January 2022 and can now be viewed through the below links. The relevant session of HyD is timestamped from 8:15 to 13:39.
Video: Science in the Public Service - 科學為民
Road Condition Survey
The MLSI system is deployed to monitor the performance of various paving materials under live traffic by capturing and displaying detailed road profiles at about 1 cm resolution for analysis of material behaviour under stress.
Uneven areas detected are displayed with their severity shown via colour map
The road profile is displayed at 1 cm interval of contour line along with point cloud results detailing the actual site conditions
Identification of Protruding Tree Branches
The MLSI system is deployed to survey protruding branches of trees alongside carriageways. Tree branches lower than a threshold level above road surface are identified. In addition to viewing the results through web browser and drawings, the potential risk areas are also displayed on mobile map applications to facilitate the maintenance parties to carry out tree pruning works, thus enhancing road safety.
Overgrown trees protruding over carriageways are highlighted by the laser scanning results
Area with different tree overgrown condition are identified on maps