Lidar is a remote sensing method that relies on pulsed laser light to measure distances to a target. The target is illuminated with pulsed laser light, and measured differences in return times and wavelengths can be used to make digital 3-D representations of the target. The term “lidar” was originally a combination of the words “light” and “radar” but it has more recently become regarded as an acronym for “Light Detection And Ranging” or “Laser Imaging, Detection And Ranging.”
Airborne lidar uses lasers to scan terrain by air. Laser light is directed toward the earth and a scanner is used to create a set of points, a 3-D point cloud which can then be used to create a model of the landscape. It is currently the most accurate way to create digital elevation models. Airborne lidar can be used to create bare earth terrain models even if the ground has features like buildings or trees.
Topographic airborne lidar is used to create land surface models. Bathymetric airborne lidar is water penetrating. Bathymetric lidar systems can be used to collect information on land, underwater terrain, and water depth at the same time, by using infrared wavelengths to reflect from land and the water’s surface, and green laser wavelengths to penetrate the water column. Bathymetric lidar can also be used to locate objects under water.
Terrestrial lidar is most commonly used in surveying. Scanners collect 3-D data in a point cloud that can be viewed immediately. Point cloud data can be processed by applications to create CAD documents, contour maps and other documents and models. Terrestrial lidar can be used to document terrain features covering a large range of scales and varying complexities. It can also be used to document patterns and pattern changes, for example, terrain changes and erosion or landslide risks, and forest growth patterns.
Mobile lidar uses scanners are attached to moving vehicle to collect data along a path.
Atmospheric lidar is used to identify, measure, and quantify components of atmosphere. Atmospheric lidar works by measuring light backscatter or by measuring the reflection from the ground to determine atmospheric absorption. It can also evaluate changes in the atmosphere, such as temperature or wind speed by measuring the frequency of back scattered light or the frequency shifts.
Contact Sales for further information on how OPOTEK can provide you with the appropriate light source for your lidar application.