Full-waveform ALS workshop - Measurement Principle and Physical Fundamentals

First presentation

Wolfgang Wagner: Measurement Principle and Physical Fundamentals

Overview:

• How does a full-waveform laser scanner work?
• Important properties of laser light
• Range determination and range resolution
• Beam pattern and spatial resolution
• Radar equation
• Cross section of different targets
• Waveform generation
• Waveform analysis → Presentation of Andreas Roncat
• Radiometric calibration → Presentation of Christian Briese



Conclusions:

• Full-waveform laser scanners depict the measurement process in its
entire complexity
- Full-waveform system are compatible with ranging systems, but not vice-versa
• Advantages
- Algorithms can be adjusted to tasks
- More echoes as in first/last pulse systems
- Intermediate results are respected
- Neighbourhood relations can be taken into account
• Calibration of the data, i.e. conversion to cross section, is essential for
physical modelling efforts
• The additional data, i.e. amplitude, width, cross section, is valuable for
segmentation and classification purposes
- Classifying terrain and non-terrain points for DTM filtering