Use of a High-Resolution 3D Laser Scanner for Minefield Surface Modeling and Terrain Characterization: Temperature Region
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
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The use of a high-resolution, ground-based 3D laser scanner was recently evaluated for terrestrial site characterization of variable-surface minefield sites and generation of surface and terrain models. The instrument used to conduct this research was a Leica HDS3000 3D laser scanner. The high-speed, highly accurate ranging system has a 360 deg horizontal 270 deg vertical field of view that delivers positional, range, and angular vertical and horizontal single point accuracies range 1 to 50 m of 6 mm, 4 mm, and 60 micro-radians, respectively. The laser is a class 3R and is completely eye-safe with a wavelength of 523 nm and spot size of less than or equal to 6 mm at a distance of 50 m. The pulse rate is 1,000 points sec with an optimal effective range up to 100 m which is capable of producing a maximum point cloud spacing of 1.2 mm in the horizontal and vertical direction. Two study sites located in the midwestern United States were used for this analysis. A very dense vegetation site Grass Site and a bare soil site with intermittent rocks and sparse vegetation Dirt Site were selected for data collection to simulate both obscured and semi-obscured minefield sites. High-density scans range 0.2 to 2.0 cm spacing were utilized for Cyra target acquisition and were commensurate with size and distance to target from scanner location. Medium-density scans range 2.0 to 5.0 cm spacing were chosen for point cloud generation of the entire sites with approximately 10 percent edge overlap between field scans. In order to provide equivalent, unobstructed viewing perspectives from all scan locations at each site, the scanner was positioned on a trailer-mounted, chain-driven lift and raised to an approximate scan height of 7.6 m above the ground. Final registration to UTM projected coordinate system of the multiple scan locations for the Dirt Site and Grass Site produced mean absolute errors of 0.014 and 0.017 m, respectively.
- Lasers and Masers