Lidars (or Laser Radar for Laser/Light Detection And Ranging) have had wide applications ranging from atmospheric sounding to water depth mapping. There is also an existing and commercially viable industry in the use of Lidars for mapping elevation of terrain. The “Terrain” Lidars used for this purpose are ranging instruments and are primarily designed to avoid‘problems’ (for Terrain sensing) associated with vegetation cover and (in so doing) are not well suited for operational vegetation measurement.

Canopy Lidar involves a unique combination of hardware and processing methods that are different from Terrain and other existing Lidar applications.  The key difference is that a Canopy Lidar records the range and intensity of returns reflected from all levels through the canopy, while a terrain lidar (airborne laser systems) only records the range to five levels at most (some systems record only one or two returns). In canopy lidars the laser beam is usually broad, creating a spot size on the ground of several metres diameter.

There are no commercial lidar systems available at present with fully digitised return signals, variable spot size and calibrated return signals. With such a combination and advanced processing software it can be shown that a very large market in detailed mapping is viable. Several bathymetric lidar systems, eg LADS and SHOALS, have digitised return signals but their specifications are not applicable to investigating vegetation.

Lidar sounding offers information about plant canopies that current remote sensing technologies, including multi-view angle and multi-spectral scanners and SAR Radars, are finding it very difficult to provide in an operational way to a large client base desperately needing the information. Lidar is not, by itself, a complete technology and will be used in company with other technologies, such as spectral sensing and ancillary information, to provide a complete, integrated mapping tool. However, it is an“orthogonal” technology in that it provides important and complementary information the others cannot.

The advances on existing Terrain Lidars that make this area appropriate for CSIRO to consider investing its knowledge and skill are in instrument developments and product development through advanced scientific algorithms and processing techniques. In particular, the instrument developments for Canopy Lidars allow the return signals to be understood in terms of forest data.

A CSIRO commissioned business plan by Leadenhall Australia Limited has identified a very comprehensive market across a range of scales from plantation to continental biomass estimation in which canopy Lidar technology combined with effective processing and algorithms is set to make information available on forests worldwide that has not been available before.