LiDAR automation drives increased efficiencies
The evolution of geospatial technology has seen rapid advancement in the last 18 months, with systems and software now available that make light work of traditional surveying tasks. Automated systems are driving organizational change in many industrial settings, yet when it comes to monitoring change, traditional tools and processes are prevalent. But, the latest remote sensing technologies are getting closer to automating industrial surveys.
From lightweight mapping systems mounted to drones, to multispectral systems with integrated cameras that allow for detailed surveys of dense, urban areas — remote sensing systems have come a long way in recent years. Laser scanning systems had traditionally been limited by both portability and affordability, something that has changed with the growing number of mobile mapping systems emerging for detailed inspection work. LiDAR technology systems are becoming more commonplace on sites. They work by using the pulsed light from a laser to calculate distance and are becoming smaller, lighter, and cheaper.
Pioneered by scientists in the 1960s, LiDAR is known as one of the most accurate ranging technologies available. Thanks to rising demand from the automotive sector, billions of dollars are currently being spent on making this technology more accessible and affordable for a range of new applications.
LiDAR has long been used by larger surveying businesses looking to accurately map and model 3D environments. From forests to urban infrastructure, LiDAR-derived data is extremely valuable when it comes to assessing complex surroundings. We’ve seen this with survey-grade laser scanners such as ROBIN, which can accurately collect about 1 million measurements per second with up to 1 centimeter absolute accuracy possible with ground control points in good GNSS conditions. These measurements can then be turned into a 3D point cloud, making it easy to interpret by surveying teams. While these dense datasets can provide detailed intelligence, it’s the ability to automatically detect change that is currently driving a new wave of innovation.
Monitoring change can be critical to civil and structural projects from beginning to end. As our urban environments grow at a rapid rate, greenfield projects are becoming more rare and, as such, a more detailed picture is needed when it comes to planning large developments.
There is always a great risk of ground movement when new works commence, which is especially dangerous where older structures already exist. Traditional pre-construction surveys can only give a retrospective vantage point when it comes to assessing change, yet LiDAR may hold the key to developing automated monitoring systems that not only improve processes but also make construction environments safer to work in.
Change detection is all about analysis — something that can take weeks of sifting through terabytes of data without the right systems or software. Because of the level of data contained in a LiDAR-derived point cloud, it can often mean hours of processing time until a meaningful representation of the survey area is produced. The internet of things has given us new expectations when it comes to data-on-demand and geospatial technology is now meeting the challenge head on. Integrated systems are now being developed that offer the ability to detect change in close to real-time.
PROCESSMONITOR LIVE was developed in response to clients’ needs to measure the thickness of sprayed concrete during application in a tunnel. Using a compact laser scanner, the system has been designed to detect millimeter changes of a surface, on demand. A scan of the target surface is carried out before work commences, outlining areas that have potentially been over or under profiled, allowing for operators to then identify where more shotcrete needs to be applied to ensure structural stability.
As each scan takes about two minutes to carry out, the process can be monitored repeatedly throughout the construction process. Surface changes are automatically analyzed and identified in the color-coded software output, meaning that operators can assess their own work without having to wait for offsite staff to process the collected data. The same type of scanner and software package is also being used in construction of a large rail expansion project, where the aim is to assist in tunnel profiling accuracy.
The scope of this type of LiDAR application not only covers tunnel monitoring, but also provides detailed and accurate acquisition and analysis for purposes such as demolition, structural repairs, and even volumetric calculations for changing masses like stockpiles.
Remote sensing technology such as LiDAR not only realizes increases in operational efficiency but also improves safety for operatives working in heavy industrial environments. Removing the need for manual inspections can go a long way toward achieving zero-harm targets on large projects. Most laser scanner manufacturers offer both long- and short-range systems that can be operated in areas that are inherently dangerous for onsite teams.
LiDAR is capable of working in dusty and dark conditions where visibility is an issue. Scanners can be set up to scan at repeated intervals, feeding back data from a safe distance. Connected scanner and software packages are adept at identifying even the smallest level of surface deformation. Automated alarms can be triggered when sensors detect change outside of set parameters, allowing for proactive steps to be taken before conditions worsen. This can give site managers the opportunity to actively monitor areas that pose a risk to both workers and project timelines, all in real-time.
Another area where LiDAR-based change detection excels is in slope stability assessments. With worsening weather conditions, slope failures are becoming more common. Railways sidings and other exposed, naturally occurring structures are most at risk of deformation. Point cloud-based change detection has the ability to revolutionize the way that monitoring surveys are carried out.
Historically, it has been impractical to continually assess slopes that are most at risk of failure in enough detail to be proactive. In applications such as monitoring coastal erosion, precursors to failure often present themselves prior to a large-scale event. Using software similar to PROCESSMONITOR LIVE, Durham University is carrying out a large-scale monitoring project of the Whitby coastline. Using a combination of terrestrial laser scanning and airborne LiDAR, it has been possible to identify change to help better forecast future events. The cliff face is monitored 24 hours a day, with scans carried out at 30-minute intervals. The results are streamed in real-time to allow analysts in Durham to see results as they are collected. Alerts are also set to warn of incidents that may suggest critical failure, which could one day save lives.
LiDAR and other remote sensing technologies are a way off being fully automated, but much of the development work relies on clients looking to develop a fully integrated data strategy. Connected systems offer industrial environments a new way of realizing efficiencies while also improving onsite safety records. It’s only a matter of time before automated, real-time monitoring becomes commonplace, saving time and money in the process.
Dana Pertea is client engagement manager at geospatial technology specialist, 3D Laser Mapping (www.3dlasermapping.com).