The concept of Light Detection and Ranging (LIDAR) is really quite simple as it involves the capability to tune the wavelength, pulse width and frequency of laser light, bounce that light off objects, and capture returning light over time to measure X,Y, and Z dimensions as well as the returning light’s intensity. The technology has proven to be quite useful for capturing 3D terrain and features, and is being used extensively to map infrastructure and natural resources.
Since the technology’s first inception in the late 1960s, LIDAR has been applied to atmospheric studies of air quality, marine and hydrographic studies, for bathymetric studies and water quality issues, surveying and mapping, as well as positioning and guidance. The technology has been tweaked and fine tuned for each subsequent application area, lending improvements back to the technology development as a whole. While all of these applications and their insight have been impressive, we’re still just scratching the surface with the capabilities of this technology.
The ability to measure and classify different intensities of the light returns means that LIDAR can be tuned to capture and record a variety of different phenomenon, both visible and invisible. The intensity can be customised for atmospheric research to pick up different signatures from molecules to understand what elements are present in our air, and can do the same in water. The signatures of the elements can then be monitored to understand changes in the atmosphere and the makeup and changes in the composition of our water bodies.
Seeing what can’t be seen by the naked eye is a key application of this technology. Coupling measurements with composition also lends itself to detect environmental changes in terms of soil composition, as well as changes in vegetation. The technology is being applied to monitor variations in how soil is compacted from as far away as a kilometer and to detect how soils have been disturbed to understand if they are polluted. The technology is also being applied in forestry to assess the overall health of forests and to detect susceptibility of forest fires.
The number of applications for LIDAR sensing of various environmental change are nearly limitless. To date, a number of different LIDAR instruments have been developed to monitor specific phenomenon. There will come a time in the development of this technology where we’ll see a highly dynamic LIDAR sensor to measure a myriad of different intensity signatures to gather far more information about how our planet is constantly changing around us.
Fusing Other Sensors
The combination of high-resolution color images on both aerial and terrestrial applications of LIDAR have provided very interesting and quick captures of reality that can be rather easily deployed in models in order to represent a virtual reality. The applications of this technology are as diverse as informing engineering and design projects to incorporation in the entertainment and game industries to inform storytelling.
The addition of other sensor on the aerial platform such as hyperspectral or thermal imaging provides even greater sensing synergy to detect a myriad of environmental measurements. Hyperspectral imaging provides a means to add to the topographic information of the 3D scan with measurements that help identify the types of vegetation with a resolution that’s only available through the assessment of the various color bands of the image independently. Through the application of thermal sensors on active fires, fire managers can get a much better understanding of fire behavior on different fuel types, informing mitigation approaches.
Multi-sensor confirgurations are proving to be a very interesting technology for scientific and surveillance use. The types of sensors and various applications will continue to proliferate, and will be an important tool in our increasing interest to monitor and understand change on our planet.
The Proliferation of the Technology
Just as video cameras were once too expensive to mount and leave connected, so too will LIDAR sensors come down in price to proliferate in areas that need constant measurement. The idea of a LIDAR surveillance system isn’t too far fetched, with the ability to measure distance, motion and composition. A LIDAR system could be used for virtual fence creation, alerting a central system when encroaching object pass a certain distance threshold. The ability of LIDAR to measure and classify would provide a means to quickly understand the makeup of the objects and would send an alert based on certain profiled compositions, such as metals or other detectable elements such as explosives.
We now have constant measurement from space with LIDAR deployed on satellites. These instruments provide fairly regular measurements on a global scale that needs to be augmented with both aerial and terrestrial sensors in order to get a wide scale of measurements. With decreasing costs of components, and more capable systems, we’ll see a proliferation of LIDAR sensors that will greatly inform us.
With increasing speed of data classifcation and analysis, we’ll gain a much greater understanding of change. And with increasing overlap of sensors at various scales, we’ll be able to aggregate these different measurements for a much greater understanding of the whole from the region and country scale all the way down to millimeters of accuracy on the ground.
Overcoming Data Limitations
One of the biggest technological hurdles for greater LIDAR utility has been the issues faces with the amount of digital storage space that is required to house the measurements, and the computing power that is needed to visualize and analyze these returns. The rapidly dropping prices in computer storage and capacity is easing some of these burdens, and the advent of cloud computing is providing whole new ways to deal with the data and visualization limitations.
By harnessing large arrays of computers, analysts are much easily enabled to dive into the details of the data. The ability to store the large amounts of data on shared machines also eases some of the burden of storage management, and makes the data much more readily and speedily accessible.
With easier data storage, analysis and integration capabilities in the cloud, the burden of collection is eased in order to proliferate more sensors. With greater capacity to utilize the data, more of the data will be looked at, which will lead to whole new application areas.
The future of LIDAR is quite bright in a myriad of ways, because of the uniqueness of its sensing capability. In a time when we need more and better means to measure and analyze our world, LIDAR technology will certainly shine in the coming decades.
- Proposed NASA LIDAR Surface Topography Mission [PDF background]
- Quantifying Structural Physical Habitat Attributes using LIDAR and Hyperspectral Imagery, Environmental Monitoring and Assessment, Volume 159, Dec. 2009
- Extracting Wildfire Characteristics Using Hyperspectral, LIDAR, and Thermal IR Remote Sensing Systems, Christos Koulas, Proceedings of the SPIE, Vol 7298, 2009