The display and analysis of bathymetric lidar waveform

Airborne bathymetric lidar is designed for surveying the depth to the sea floor or objects under the water. Comparing with the sonar system on board of ships, airborne bathymetric lidar is much more efficient for area with shallow water. It is also featured with higher safety for areas with rocks or other objects which threaten the ship. The data analyzed in this study were collected with an Optech SHOALS system. There are four channels, including an infrared channel with 1064 nm wavelength, two green channels with 532 nm wavelength, and one channel for Raman scatter with wavelength 645 nm. While the depth can be extracted reliably with algorithms, human interpretation is a must for waveforms of turbid water and shallow water. In these situations, the visualization method plays an important role. Some basic functions, including read in and display, is developed with Matlab in this study for an exploration. It is concluded that besides the dynamic link to planimetric and three dimensional viewing windows of waveform, different scale schemes and overlay of extracted features would be also helpful in the waveform visualization.