Seminar about centimeter positioning with GPS in forest

This weeks seminar is about centimeter positioning inside forest using a GNSS-receiver (Global Navigation Satellite Systems). Thomas Hörnlund from Svartbergets Field Research Station will share his experiences from measurements with the Trimble GeoXR 6000 GNSS receiver.

This is the last seminar for this year and we will be back with more seminars in January 2017. If you have suggestions for topics, please contact Mattias Nyström.

Stationary and mobile laser scanning

This weeks seminar was given by Johan Holmgren and he shared the results from field tests with three different mobile laser scanners. The three scanners were:

  • ZEB1 with 3D SLAM
  • Velodyne VLP 16 with stereo video cameras and 3D SLAM
  • Leica Geosystems Pegasus Backpack with 3D SLAM

The presentation can be found here.

Next weeks seminar (24 November) will be given by Kenneth Olofsson. He has developed methods to automatically detect tree locations and shapes from stationary terresterial laser scanning data. The title of the seminar is: “Terresterial Laser Scanning: Can we see the wood for the trees?”

Can we see the wood for the trees?
Can we see the wood for the trees?

Forest in virtual reality

Here is a short video from this weeks seminar where Henrik tries out the HTC Vive (Virtual Reality). We have converted a point cloud created from drone images to the virtual reality environment. On the screen in the background you can see what Henrik sees in the headset. With the headset on you head, you see it all in 3D as well.

Next weeks seminar will be given by students from Umeå University who is developing a platform for a mobile laser scanning system. They will give an overview of their work so far. More information about the seminars.

Forbidden to use camera on drones in Sweden

Swedish radio interviewed Mattias Nyström about the recent judgement in the court that interpret that a camera on a drone is the same as a surveillance camera. This means that you need a permission from the county government to use a camera on the drone. This permission is normally only given to prevent crime, so not sure if we can get this permission. Hopefully the law will be updated, but this can take some time. Luckily we have about 600 Gb of photos collected this summer and autumn that we can use meantime.

Link to interview in the Swedish radio, in Swedish

Link to report in ATL (Lantbrukets Affärstidning), in Swedish

Jonas conducting a flight at a research area in Remningstorp.
Jonas conducting a flight at a research area in Remningstorp.
A flight we did in connection to a planned forest fire in the beginning of the summer this year.
A flight we did in connection to a planned forest fire in the beginning of the summer this year.

Next seminar: Try forest in virtual reality

The seminar on the 3rd of November (14:30-15:00) will be a demonstration of the Virtual reality equipment in the lab. We will also demonstrate portable systems. Come and try out a birch forest scanned with our high resolution terresterial laser scanner and a colorized point cloud generated from drone images.

More information about the seminars in the lab.

screenshot-vr-anna-lena

3D fly through of Flakaliden forest

Flakaliden Research Park, where effects of climate and fertilization are studied, was surveyed by a drone taking about 700 pictures. The drone was equipped with a consumer camera (Sony a5100) and the images was processed to a very dense point cloud and very high resolution orthophoto (GSD 2.3 cm). A fly through of the point cloud is presented in the video. More information about the research at Flakaliden.

Terrestrial laserscanning in virtual reality

The HTC Vive Virtual Reality equipment is up and running in the Ljungbergslaboratory. Oscar was the first student to walk around in a terresterial laserscanning point cloud. Thanks to Mikael Hertz for generating the VR content from the point cloud.

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Oscar, one of the master thesis students, walks around in a 3D point cloud from a forest scanned with our Trimble TX8 laser scanner.
screenshot-vr-anna-lena
This is what you see and move around in in the headset.

Parrot Sequoia arrived!

The drone optimized multispectral camera, Parrot Sequoia, just arrived to the lab today! The camera collect images in four defined wavelength bands as well as a normal RGB sensor. More information about the camera.

In contrast to many other users, we plan to use the camera to capture data of forest. As soon as we have some footage to show, we will publish here on rslab.se.

The camera captures images (1.2 Mpx) in the following wavelength bands:

  • Green 550 nm (40 nm bandwidth)
  • Red 660 nm (40 nm bandwidth)
  • Red edge (10 nm bandwidth)
  • Near infrared (40 nm bandwidth)

In addition to the four narrow wavelength bands, the Sequoia has a RGB camera with 16 Mpx resolution.

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Unboxing the lab’s new Parrot Sequoia.

SLUs drones goes thermal!

3DR Solo, equipped with Flir Vue and GoPro over prescribed fire.

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
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.

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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.
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.
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.
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.
Sunset through the smoke.
Sunset through the smoke.

Jonas Bohlin and Mattias Nyström