How Are Point Clouds Made?
Point clouds make it incredibly easy and convenient for researchers and scientists to remotely measure the size and shape of objects located on the earth’s surface that cannot be accessed easily due to their surroundings. Point clouds enable surveyors to create 3D models of roads, bridges, motorways and embankments, even those that experience a great deal of traffic.
Over the last few decades, point clouds have become crucial for government bodies and privately held organisations for collecting data. This data not only helps in geographical development but also guides them in national defence and security-related operations. Our premium CAD application — TopoDOT — makes it easy for organisations to process this information and derive accurate results quickly and easily.
How Are Point Clouds Created?
To create point clouds of any object or surface, researchers use laser scanning. While first executed in the 1960s using basic projectors, cameras and lights, laser scanning became more sophisticated in 1985. High-quality equipment using white light replaced simple scanners, making it easier to gather data. At present, light beams are used for capturing the point clouds of objects, surfaces and buildings. Other equipment used in this process include sensors, lasers, inertial measurement units, global positioning systems, photodetectors and receiver electronics.
In order to collect more accurate data, the LiDAR (Light Detection and Ranging) system was developed, which throws light waves at the target surface, object or building using a scanner. The LiDAR system takes into account the total duration it takes for these waves to hit the object and return to the scanner. As soon as this data is captured, the LiDAR system calculates the total distance of the target object based on the light velocity.
Today’s LiDAR systems are advanced enough to shoot up to 500,000 pulses of light a second, which creates dense data sets. This data set is essentially a 3D picture called a point cloud, with each pixel defined by an XYZ coordinate. Engineers can use these point clouds to create 3D maps of their surroundings and objects. Using CAD (Computer-Aided Design) software, highly accurate 3D models and meshes can be extracted to be used in fields such as construction, architecture, manufacturing, medical imaging and 3D printing.
The Use of Point Clouds in Road Surveying
Road surveying is one of the most challenging fields when it comes to data collection. Since vehicles are moving 24/7 on roads, it’s practically impossible to vacate the path to collect data. This is where point clouds collected by LiDAR or photogrammetry are highly beneficial and, in fact, crucial.
During this process, the LiDAR system is installed on a moving vehicle known as Mobile LiDAR or Mobile Mapping, so that it can transmit laser pulses onto the road surface without disturbing traffic. These pulses reflect off the road surface and document the way for researchers to create a 3D map, which is made of point clouds showing the Topography (shape, size and length) of the surface, as well as any objects on the road.
These point clouds then go through the point cloud registration process, where they are imported from the 3D scanner using dedicated software. The total time taken to perform this process can vary due to several factors, including the software used and the size of the data. Once the point cloud registration is complete, the point clouds are imported into a CAD application such as Bentley Microstation, AUTO CAD, or TopoDOT to design 3D maps and models or extract features.