Jonas Bohlin – Page 2 – Ljungbergslaboratoriet

Ljungberglab seminars: Forest management plan by Drone | Tree species from multi-spectral laser.

The coming two Thursdays, 22nd and 29th of June, we will have two master thesis presentations!

Welcome to the Ljungberg lab at 14.30!

SLU at ELMIA WOOD

We are ta Elmia Wood in the DroneZone talking about using drones in Forestry.

Seminar: LiDAR and archaeology: the importance of ground point classification

Master thesis presentation: Control Assessment Using Drones

Seminar: Tree species classification using multi-spectral Lidar

Arvid Axelsson will give a presentation on his on-going work with tree species classification using multi-spectral lidar.

The scientists at the Ljungberg Lab at the Swedish University of agricultural Sciences in Umeå went for a two day field excursion to test thermal cameras and new drones. Joining the students at the Fire Management course at the Forest faculty, who were going to make a prescribed burning of a 20 ha clear-cut. We wanted to test our new Solo helicopter drone from 3Drobotics and to capture thermal video and images from our Flir Vue camera. We also wanted to test the thermal camera in our fixed wing Smartplane drone.

We started by capturing RGB images from 200 meters above ground with the Smartplane before the fire was started. From this imagery we created a 7 cm Ground Sampling Distance (GSD) orthorectified image mosaic. Which could be used for describing the pre-fire state of the area.

Pre-fire orthophoto original wirh 7 cm resolution made from Smartplanes mapping system

We started by capturing video with both visual (GoPro, with modified lens) and thermal video (Flir Vue Pro 13mm 640×480) of the controlled burning (prescribed) of the clear-cut.

3DR Solo with GoPro and Flir Vue Pro, the cameras are tilted forward to acquire oblique video.

The video streams were later synchronized and fused to a side-by-side video using a software made by engineering students (an earlier project at the Ljungberg Lab).

Forest fire, fusion of thermal and RGB camera

Forest fire, thermal and RGB camera side-by-side

Under the duration of the controlled burning we flew the thermal camera multiple times, with the purpose of acquiring aerial thermal and visual (RGB) images to describe the burn process and to test the usefulness of having a thermal camera to find hotspots or ground fire hours after the fire front have passed an area.

3DR Solo ready to photograph controlled burning with thermal (Flir Vue) and visual (GoPro) cameras.

Smartplane ready to be launched for thermal mapping.

This will be evaluated later, when all data sets had been processed to orthorectified imagery and also to 3D point clouds.

An image taken with a GoPro camera from 80 meters altitude. The yellow border shows the extent of the thermal camera. Note the person walking on the road.

Same as georef1_rgb.jpg, but a thermal image overlaid. White color is warm and black is cold. Note the hot area on the right side of the road which only can be seen in the thermal image. — Same as above, but a thermal image overlaid. White color is warm and black is cold. Note the hot area on the right side of the road which only can be seen in the thermal image.

An image taken with a GoPro camera from 80 meters altitude. The yellow border shows the extent of two thermal images. These images were taken about 12 hours after the fire front had passed the area.

Same as georef2_rgb.jpg, but two thermal image overlaid. White color is warm and black is cold. Note the hot spots on both side on the road only seen in the thermal images. — Same as above, but two thermal image overlaid. White color is warm and black is cold. Note the hot spots on both side on the road only seen in the thermal images.

Jonas Bohlin and Mattias Nyström

Seminar – Removing the topographic effect from satellite data

On Thursday (21st April), Heather Reese, Head of Remote sensing division at SLU in Umeå, will give a seminar about “Removing the topographic effect from satellite data with the new 2m DEM”. It is scheduled to 14:30 in Ljungbergslaboratoriet (1st floor in the SLU building).

Mapping excursion to Innertavle estate

Today, the teachers and students of the Ljungberg lab, went to SLU’s new forest estate in Innertavle, close to Umeå. This forest is going to be used for teaching and research purposes. Our aim was to map it with a drone to get a high resolution orthophoto map and 3D data before the winter comes.

Mattias is fixing with the drone to get us in the air (in the background students making fire).

We sprayed red crosses, which are used for ground control points (GCP) to reference the images into the national coordinate system. These where to be positioned after the drone flight using a survey grade RTK-GNSS.

Unfortunately the winter came during the drone flight! Making it a very hard job to find the GCPs both when trying to position them and in the images when doing the image processing.

But we got some result! Here is a low resolution (GSD 29 cm) orthophoto of the eastern half of the estate (click image for full size). The final products will have better geometry and resolution.