Laser scanners use active laser triangulation, or a phase shift method, to measure the complete morphological structure of plants in three dimensions . The raw data is used to calculate a point cloud which provides detailed information about plant growth and movement. This process is faster than other image analysis techniques and point to point accuracy of 0.25mm is achievable. Near infrared scanners allow daylight scanning while minimising any interaction with plant physiology.
Laser scanners are available in different versions, from simple Lidars over high-resolution scanners to multi-spectral laser scanners.
 Paulus, Stefan; Schumann, Henrik; Kuhlmann, Heiner; Léon, Jens (2014): High-precision laser scanning system for capturing 3D plant architecture and analysing growth of cereal plants. In: Biosystems Engineering 121, p. 1–11. http://www.sciencedirect.com/science/article/pii/S1537511014000166