Laser scanning is a measurement method that captures the three-dimensional structure of targets accurately and efficiently. Already it is used in self-driving cars, crime scene investigations and land surveying.
Laser scanner sends laser light pulses of a few nanoseconds which reflections’ are detected by the scanner. The scanner calculates the distance to the target based on the time difference of the sent and reflected light. This measurement can happen even a million times per second in the scanner resulting in a three-dimensional point cloud of the environment with information on the intensity of the reflection.
Samuli Junttila investigated how this reflection information can be used to measure the health condition of trees. The laser scanning based method developed by Junttila can be used to measure the water content of leaves and needles and to detect changes that can not be seen by the naked eye.
The application of this technology is essential for the sustainable utilisation of forest resources around the world. It can be used to predict forest condition and develop forest management to prevent large-scale damages. Climate change increases the amount and intensity of drought, pest insect and storm damages. Laser scanning can have a crucial role in reacting to the on-going changes.
Junttila defended his PhD at the University of Helsinki on 7th of June with the title “Utilizing multispectral lidar in the detection of declined trees”.
In addition to the traditional PhD thesis, Junttila has produced a popularised summary in the form of a rap song and a music video. His PhD defense was not in the form of rap battle though.
“I wanted to do this because research needs to be brought to the general public in an understandable form. Also, I think that the image of researchers' profession could be boosted. This project was a great way to combine my interests and have fun while doing it”, says Junttila.
Music and video production was done by Junttila and other creative professionals. Financing was provided by the center of excellence in laser scanning and the Department of Forest Sciences at the University of Helsinki.