Calibration of a Terrestrial Full Waveform Laser Scanner

Recent advances in Light Detection And Ranging (LiDAR) enable digital acquisition and storage of the entire waveform of backscattered laser pulse energy. Pre-requisites for extracting target radiometric and geometric properties via waveform analysis include defining a model for accurately determining peaks in the return energy waveform and a method for transforming waveform peak amplitudes to absolute reflectance values. The development of a system response waveform model and reflectance calibration curves for a terrestrial LiDAR sensor is described and the results compared to expected values. Our analysis shows that overall system response varies considerably over the dynamic range of the instrument, requiring the development of an empirical template to properly estimate the expected system response at a given input signal amplitude. Finally, it is shown that the relationship between target absolute reflectance and raw waveform peak amplitude varies considerably with range to target, requiring a distance dependent model for conversion of raw amplitudes to absolute reflectance values.