Traffic cameras installed in city road intersections play an important role in accident reduction and accident prevention. The feeds from the cameras are normally viewed in the control and monitoring centres by traffic police personnel and operators. They help detect traffic rule violators, identify the vehicle number and register complaints with time-stamped documentary evidence for legal procession, if needed.
Determination of the actual height and view angle of the cameras (for assessing line of sight) to detect the pedestrians and vehicles plying in the roads is essential. Earlier the activity of ascertaining the view-shed of CCTV cameras used to be based on human judgment on the field. With the advent of Light Detection and Ranging (LiDAR) technology, this activity is being carried out scientifically.
Genesys International has developed innovative solutions based on LIDAR technology for safety and security planning in Smart Cities. As part of the project implementation in an Indian Smart City which is implementing a CCTV-based surveillance system, Genesys provided the required feasibility tool with 3D models of real-world objects. These models were derived from LiDAR datasets, for viewshed/blind spot analysis with respect to various camera locations, positions and angles.
Genesys deployed advanced Mobile LiDAR technology to solve the problem with high spatial accuracy and executed the project faster than conventional methods. The results are being used not only for project planning, but also for project implementation and ‘as-built’ design updates. Besides, the spatial data comes as a baseline ground reality ‘as-is’ for Smart City command and control centre operations.
Van Data Collection (VDC): In this process, the vehicle mounted with the TOPCON IP-S2 LiDAR mapping system was used to collect the spatial features. The base station was set up at an appropriate location from the area of interest to be surveyed. The captured data from the LiDAR system had millions of point clouds and each point of the cloud data was represented with accurate X,Y, and Z details with reference to the base station.
Among these cloud points, appropriate point cloud data was used for reference points. A plan was kept in place to finalise the region to be covered, therein defining the route that needed to be taken. Once the routes were defined, different vehicles were deployed across different regions in the city for data collection. The data collected was then sent to the Genesys production floor in Mumbai for bulk data processing.
Data Processing: Verification and inventory of data received for bulk processing determines the completeness of the data. The received data was added in an MDB to track all the trajectories received till date. Trajectories were split grid-wise with a standard measurement of intra 1 km for allotment purpose. After completion of grid creation by cutting the trajectories, the data processing team released the grid and trajectory-wise details to the production team to initiate feature extraction.
LiDAR Feature Extraction: Feature extraction was carried out using customised software such as “Spatial Factory” and ArcGIS desktop tools. Features were extracted from LiDAR and Pano datasets only. Features which were obscured due to parked vehicles, vehicular movement, and tree cover could not be extracted. In this project process, no foot survey procedure was conducted to capture the data on field.
Deliverables: All the junctions identified by the client were delivered within a 250-metre radius as per the shared lat/longs in AutoCAD and PDF formats. Accuracy of 10 to 25 cm for 1:1000 scale map/drawing was achieved for the output. A GIS application was integrated with map data. A viewer was provided along with the user manual.
A road junction survey using LiDAR technology for preparation of 2D propagation drawings in 250x250 metre grid with a 50-metre inner grid for junction drawings in .DWG and .PDF formats is the requirement of every Smart City wherein CCTV cameras are planned to be installed across different sensitive spots. Integration of data into a GIS-based 3D visual platform, combined with the point cloud, gives the operators an integrated picture.
Genesys applied Mobile LiDAR Survey (MLS) for acquiring accurate street level building profile data to meet accuracy expectations and the acquired MLS data was supplemented with high-resolution panoramic imagery, resulting in a rich GIS dataset, empowering security planners, implementation engineers and contractors in their decision making and execution abilities via accurate drawings.
The as-built data and underlying point cloud data along with street level panoramic images became the foundation as authentic visual data for command and control center operations. Data could be measured in 3D, enabling users to experience and work directly in real-world conditions by viewing and planning on a desktop-based environment.