full-waveform laser scanning, (FWF)
Full-waveform laser scanning involves high-resolution time sampling of the entire backscattered signal energy, allowing the 3D point clouds acquired in this way to provide very precise images of the objects being measured. This LIDAR technology provides high range accuracy and low noise and delivers information about the pulse shape for each point. For example, the acquired waveform signals can be analyzed using Gaussian decomposition to accurately identify peak values. FWF provides high resolution for multiple targets and allows straightforward radiometric calibration.
The so-called multispectral laser scannings provide multi-wavelength point clouds from which insights into the three-dimensional distribution of spectral data can be obtained. Multiple lasers with different wavelengths or a tunable laser are usually used, since they offer eye safety and a reasonable signal-to-noise ratio. Alternatively, a ("white") supercontinuum laser can also serve as a photon source, but while this offers a continuous spectrum, the adjustment of the laser power is difficult, as a suitable compromise between sufficient measurement signal strength and eye safety must be found here. Whichever laser source is chosen for this approach, ADCs are usually used for data acquisition in these full-waveform digitizing scanning LIDARs.
Full-waveform LIDAR is characterized by its particular precision, especially in complex target situations such as natural or steep surfaces. LIDAR devices that can process multiple reflections also capture information about objects that are partially obscured by vegetation or the like. They are therefore also used for aerial ecological vegetation studies, for example, although the area performance achieved is significantly lower compared to single-photon LIDAR. In exchange, waveform LIDAR provides the processed point clouds in near real-time.