Laser Digital Terrain Mapping System (LDTM)
Pavemetrics® Laser Digital Terrain Mapping System (LDTM) allows for the mapping of road surfaces in 3D with unprecedented accuracy and resolution.
The Laser Digital Terrain Mapping system (LDTM) uses laser line projectors, high speed cameras and advanced optics to acquire high resolution 3D profiles of the road. This unique 3D vision technology is integrated with GPS and inertial measurement units (IMUs) to accurately track vehicle position and to correct 3D scans for the effect of vehicle motion.
The LDTM acquires road surface data with 1 mm resolution over a 4 m lane width at survey speeds up to 100 km/h. Both 2D image and 3D data are simultaneously acquired at a rate of up to 45 million points per second and are seamlessly merged together into a high accuracy digital terrain map.
Accurate Results in Minutes Not Days
Pavemetrics data processing tools automatically generate break lines and detect lane markings, road edges, curbs, measure drop-off of unpaved shoulders, road profile, curvature, slope and crossfall.
The Most Widely Trusted Sensor
The LDTM leverages Pavemetrics prolific LCMS® technology; with more than 100 units in use around the world, the LCMS is hands-down the most widely adopted and trusted sensor of its kind.
The Right Data Formats
Data processing tools included with the LDTM give you the option of creating LAS and Bentley MicroStation formatted files to make incorporating your outputs with the rest of your project easy.
With Room to Grow
The more data items you can collect in a single pass, the more value you can deliver to your clients. Because the LDTM is based on the same sensor hardware as Pavemetrics’ prolific LCMS system, automated pavement condition inspection capability can be added to your LDTM at any time without the need for hardware upgrades.
Key Features
- Automatic generation of breaklines
- Detection of road edges, lane markings, curbs
- Day and night operation
- Low power consumption
- High resolution (1 mm) downward images
- Slope, curvature and crossfall
Specifications
- Millimeter accuracy digital terrain models
- 45 MHz point generation
- 1 mm longitudinal scanning interval
- 1 mm transverse resolution
Author: John Laurent, Richard Fox-Ivey and Benoit Petitclerc (Pavemetrics)
Abstract: Road Transportation and Public Works Departments (DOTs) typically perform annual pavement condition inspections to record cracking, rutting, smoothness, etc., which serve as an important input into Pavement Management Systems (PMS) software. Road surface defects are analysed by PMS software in order to model the deterioration of pavements and to make budget and performance-based recommendations regarding which roads to maintain, what maintenance treatments to apply, and when to apply them. Increasingly pavement condition data are captured using high-speed 3D lasers which acquire the 3D shape of the road surface. These technologies automatically analyse 3D scans in order to detect and quantify pavement defects. There is an untapped opportunity to enhance and repurpose this data in order for it to also be used for the design of reconstruction projects. In the past, designers have relied upon traditional survey to capture elevation data for volumetric estimates as well as Preliminary and Final Designs; however, traditional surveys require lengthy road closures, are costly, limited in resolution, and present dangerous working conditions for survey staff. Alternatively, 3D pavement condition survey scans can be enhanced through the addition high-accuracy Latitude, Longitudinal and Elevation data (via “blended” GNSS + INS systems). When further processed, these 3D scans can provide elevations with comparable accuracy and repeatability to traditional methods, but for a significantly larger number of measurement points (as dense as a 1mm x 1mm grid), without the need for a road closure, in a fraction of the time. Thus, repurposing these data presents a significant opportunity for DOTs to reduce their survey costs, minimize traffic interruptions, decrease turnaround times, improve staff safety, reduce milling, paving and compaction quantities, and deliver superior road surfaces. This paper explores the necessary hardware and software as well as the steps required to generate high-accuracy elevations from 3D pavement scans. Importantly the accuracy and repeatability of this new method is thoroughly evaluated through direct comparison to a large network of surveyed control points.
Optimizing Surface Characteristics Data Collection by Re-Using the Data for Project Level Road Design
Authors: Benoit Petitclerc, John Laurent and Richard Habel (Pavemetrics)
Abstract: This article proposes a way to reuse the 3D road surface condition data to create road surface model and avoid expensive manual road surface surveys that require road closures. This new approach provides a way to tag collected high resolution high accuracy transverse road profile data acquired by a LCMS system (Laser Crack Measuring System – Pavemetrics) with a highly accurate GNSS-INS system (Applanix POS-LV – Trimble) to measure both road surface condition and to generate a survey grade accuracy terrain map of any road surface. The information provided by the 3D LCMS system, DMI, Applanix POS-LV, GPS with local RTK corrections and post processing (POSPac-Trimble) software are used to generate the road surface models with repeatable measurements and accuracy compared to surveyed control points. This process results in significant productivity improvements, optimization of the quantity of material that needs to be carried in and out, lower survey costs, decreased traffic interruptions and improved safety of surveyors while improving the quality and resolution of the road surface models.
