Since the last 10 years, LiDAR technology has evolved toward many media types, allowing new approaches when acquiring terrestrial data. The high acquisition speed and precision of mobile LiDAR go well and above data acquired by aerial LiDAR. It has since become a real asset to accomplish complete 3D surveying of cities with constant residential and industrial expansion. In fact, these qualities allow a new world of innovation. Here is the elaborated method used by our experts at Geolocation to process data acquired by mobile LiDAR.
Mobile LiDAR data acquisition
LiDAR is a technology that gives the possibility to generate point clouds from data captured by fixed sensor positionned on a vehicule. Synchronized to an inertial platform (IMU) and a GNSS signal, the generated points are then georeferenced at a speed of 1 million points per second for each integrated scanner. Finally, some ground control points are used to finely calibrate the point cloud and guarantee the quality of the data. In the optic of bettering the total capture time of any area, many systems include a second scanner. This allows the operator to only do one pass per street, a big advantage in urbanized areas. But that is not all; a high resolution camera is also added to the system and gives the option to colourize the point cloud afterwards.
In this case of use, trucks and minivans show themselves to be the appropriate choice of vehicle. Having a wide base and the ability to have a rack on the roof, these vehicles give the best chances at a stable system.
Extraction
Entity extraction from the point cloud gives us the possibility to segment and position objects of interest. Geolocation creates its own algorithms to segment the point cloud using dimensional analysis to separate objects of different color and intensity. The more unique an element’s signature is, the easier it is to separate it from the point cloud. It is then possible to classify the element’s points or to simply extract its XYZ position. The data’s relative and absolute precision open up a new world of possibilities and applications. Thanks to our expertise, we can now accomplish technical surveys at any time straight from the point cloud and as accurate as if done manually. Even during winter times, it is now possible to create and prepare surveys and be ready for the next season.
Final product
The most impressive and useful product in mobile LiDAR is without any doubt the colorized point cloud. It allows the user to navigate through any captured area at any given time and even allows taking measurements. Dynamic and flexible, this product can be published and consulted on an online platform by end users.
Recent realizations
Constantly developing its expertise, Geolocation has been an actor in the implementation of mobile LiDAR in the province of Quebec by accomplishing major projects. Since 2011, year of the first contract assigned by the Ministry of Transport of Quebec, our portfolio has not stopped growing with new studies.
Notably in 2020, Geolocation was implied in the realisation of a 200km project of continuous acquisition. Geolocation successfully classified the point cloud and extracted more than 16,000 ponctual entities and 1000km of linear entities. Even more, the final product was released on an interactive platform and the data certified by our professional team of land surveyors. We also offer a multitude of derivative products unique in Quebec. Like but not limited to, the creation of high resolution raster images of the ground and 3D models of the ground or buildings.
Let us know your particular needs at info@geolocation.ca and our team will provide you with a tailored product answering your needs.