Allan Carswell, the founder of the Canada-based LIDAR company Optech, provided the opening keynote for SPAR 2010 in Houston this morning. Carswell has been working with LIDAR since 1960 and has been responsible for a great degree of technological advancement as well as the application of the technology in areas as diverse as the capture of measurements of the built world to use on Mars exploration missions.
Carswell reminded the audience that the concept of LIDAR is really simple, and that it’s the unique quality of this light source that makes measurement possible. With lasers we are able to tune wavelengths and modulate the pulse width and frequency. The returned light provides measurements of X, Y, and Z measurements based upon the time it takes for the light to return, but we can also measure the light intensity which provides a means to classify the objects that the light strikes.
Carswell’s first LIDAR project was in 1968 to measure smoke plumes for pollution and air quality with a laser instrument that won the inventors the 1964 Nobel Prize in Physics. From those early days of atmospheric mapping, there are now LIDAR instruments on satellites (NASA Calypso) that can measure air quality and atmospheric changes on a global scale. He continues to be involved in atmospheric applications of the technology with development of Raman LIDAR that can provide species-specific returns to measure such things as natural gas or ozone in the air. The fluorescence spectrum measurements that are available from this technique can detect different environmental effects on vegetation, chemical soil pollution, mechanical soil disturbance, etc.
Marine applications are a growing area as the LIDAR as the laserc can penetrate 40 to 50 meters of water to capture the bathymetry, water conditions and sub-surface resources. A combination of technologies with both LIDAR and hyperspectral instruments allows you to understand how murky the water is
to get a chlorophyl count and by capturing bottom reflectance measurements you can classify the bottom. With advancements there are now Coastal Zone Mapping and Imaging projects that can capture both shoreline and coastal water at the same time.
There have been a number of advancements on the measurement and mapping of the build environment with tripod mounted systems that can measure both inside and outside of a building. The combination with Lidar 3D Color Imagery provides very realistic captures of textures and colors that make this technology appealing in both building and construction as well as entertainment industries. The capture of complex built structures such as bridges and plants are providing a whole new area of opportunity.
Mobile mapping systems have risen to prominence this year as they can look both forward and backward (in order to omit shadows) and can measure at highway speeds a great deal of data. Carswell provided examples of bridge scans and wires in rural settings as well as dense urban environments including the scanning of the Coliseum of Rome from a moving vehicle. With just a 10-second drive by of the Coliseum, a tremendous amount of detail was captured. These new capabilities are a disruptive area for data collection with a tremendous amount of opportunities.
Carswell spoke about the future development of the technology with greater and greater pulse rates of lasers and the measurement of multiple returns for whole new levels of accuracy and measurements that can be classified. On the software side there is a need and interest to provide synergy among the different sensors and to automate the data collection.
Carswell was asked about the application of these tools for global warming and global change. He asserted that atmospheric LIDAR are leading the way, particularly at the poles, for our understanding of warming. The tools are also of great use in improving our energy efficiency, with measurements of buildings for retrofit. He also discussed the application of coherent LIDAR systems that send out a beam to measure wind several kilometers out for precise wind measurements that avoid for wind farms.
The level of potential for this technology was referred to as the LIDAR Revolution, given the great potential. Carswell indicated that we’re just scratching the surface and there are all sorts of potential applications with exponential growth that will be accompanied by a great degree of changes in all aspects of technology application from planning, procedure, data acquisition and assimilation.
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