Laserscanning in Bahnprojekten with Nikoloaus Studnicka | RIEGL

So thank you very much for the introduction. Um I'm working for the company Regal. Uh we are a laser scanner manufacturer uh with a booth in this hall. Today I want to speak about uh terrestrial laser scanning from the tripod and the UAV laser scanning especially for the application railway scanning. So we called ULS unmanned uh laser scanning and terrestrial laser scanning TLS. Uh want to show how to scan how to survey uh the rail track the rail switch or the rail uh station. So on the left side you see a photograph on the right side the point cloud. So this is our uh result the point cloud after different scan positions. So we have a lot of uh specifications. Uh one of the most important is that we can take one scan position per minute. So every minute you put the scanner to the next scan position. Uh we have a resolution of 6 mm in 10 m distance. At the same time we take uh the images and we have a GNSS receiver. So the scan time is uh less than 30 seconds. But if you move the tripod to the next uh scan position, it's approximately one per uh minute. It's eyes safe. We have different uh camera systems, a internal camera, uh panoramic camera if possible for indoor applications and uh also a Sony ILX uh if you want to have a 61 megapixel camera. um out of the photograph of the internal camera we can uh generate uh panoramic uh 200 megapixel panoramic images. So uh the main points of that scanner is that we have a real time onboard registration. Every laser scanner manufactures that it's real time it's onboard and so on. But this is really extremely robust. We are using uh voxal files uh fa transformation. We have a second processor inside of the scanner. Um, so it's super impressive. You are in the field. Uh, and you can see how all the scan positions are registered. No need of a tablet or something like that. Uh, so you really can concentrate. Uh, especially in this environment um on laser scanning itself. Uh, we have 30 second scan time. Uh, we have a range for the 2.2 2 MHz of 220 m. Uh, of course, if you reduce the pulse repetition rate to uh 140 kHz, we can measure up to 1 uh,000 m and it's lightweight. It's a 6 kg scanner. So, we come to the first project. Um this uh rail track uh was closed uh because uh there were a landslide and uh we made some tests also with uh special control points. So uh one of the tones are black and white targets. Uh some of them are so-called gao target. Gao GV means graph targets. That's a specialty of Austria, Germany. Uh so the German railway uh company they want to have this uh yellow uh target. On the right side we see the scanner. Um my colleague uh scanned on two different days in um about 8 hours 342 scan positions. A single scan uh with more than 30 million points uh six millimeter uh resolution in 10 meter distance looks like that in uh with the so-called reflectance which is range independent. But if you uh colorize the point cloud, it's a colorized point cloud from a single scan position. Uh if you check uh also on top um the cables uh are uh really clean. After the scan overnight we click on our so-called one-touch processing wizard uh to convert the scans to filter scan register if it's not registered already in the field. Fine adjustment that's a we call it multistation adjustment. It's a block adjustment of all the scan positions. Um we create banoramic images, we colorize the point cloud, we mark the moving object uh so we can eliminate it and uh we can create point clouds. So in uh green you see uh the track of course we can measure more than 200 mters but in this case only the rail track was important. uh from the customer we uh got some uh control points measured by the total station uh and if you compare the total station with a laser scanner you can say anything about the accuracy of the survey. We have a so-called Geiosis manager inside of our software. It's called Rise Cam Pro. It comes uh with the scanner with a serial number license. So you can uh use this software. you can install the software on different laptops uh all the time it's the same license and in this case we used the coordinate system DBF 2016 so whenever you have uh the the right code uh of the coordinate system then you can use it this special target also uh reflecting targets are implemented in our software. So you if you are in the field you make a panoramic scan you press the button find reflectors it will find the reflectors and will take a fine scan the fine scan with a reduced laser power so-called fine scan uh measurement program because then we get less noise on the high reflecting uh retroreflecting uh targets. So this is a fine scan. All the uh fine scanned uh reflectors are in this list. Uh all the uh coordinates of the total station on the right list and with the press of a button we can find the link between them and then we start the multistation adjustment. That was a special um project. Uh so these uh control points are the black and white targets. On the right side we have the kau targets and at the end uh we get uh the result. It's the standard deviation uh between the total station and the laser scan and if you work for the uh German railway you have to be better than 5 mm. The point cloud itself of a bridge for example looks like that. uh also with true color. Let's go a little bit into the detail of the track itself. So if we make a cross-section uh you can see it in the autoonal view and if you come a little bit closer um to the rail then you see the quality of the point cloud over the whole length. Um and um this is a autocon view. This is a perspective view with true color on top on the same rail track. That was the first uh project on top. Here is the second. Um you see again the uh registered point cloud. Um this is a screenshot of the graphical user interface of the screen of the laser scan. So this is what you see in the field. You see all the scan positions how they are registered in the field. every scam position one minute. After processing the colorized point cloud with a different scan positions in Rice Cam Pro shows uh the rail switch and the customer want to have some details. Uh they wanted to know uh the the holes which are a special reference. Uh so they checked the point cloud. Um as you can see I jumped now I'm responsible for terrestrial scanning uh in our company. So I go now to the uh UAV based laser scanner which is not uh really my my strength but we are using um this uh scanner the VX 120 uh on the on the UAV. So it's very lightweight 2 kg. Uh has a field of view of 100°. A specialty is the Nadia forward backward uh view. I can show you afterwards. A very high measurement rate of 2.4 MHz. Um so um if you look to the uh specification uh depending on uh the reflectivity of the target we have a maximum range of 400 m which means uh the maximum operate flight attitude is uh between 110 and 200 m. if you get permission to fly in Germany, but that's another topic. So, what is the uh Nadia scanning is clear. Uh we look downwards, but there is a rotating mirror inside. So we have also a forward uh and a backward uh backward uh looking laser beam in order to see the front and the back uh side of the targets. On the left side you see the system uh which contains uh the laser scanner itself. Instead of a very high high price IMU, we are using our re relock uh unit um and the Sony Alpha 7 R4 uh camera 61 megapixel as platform. The standard platform is a DJI Mattress 400. Uh and uh at that day my colleague flew four different flights in different hats and uh we got accuracy of about 2 mm. So this is after the block adjustment uh we got uh the 2 mm between the different uh scans and the black and white targets at that time. So a point cloud um 2D and a 3D view. And if you uh go a little bit closer uh to the rail track even here you uh can see the quality of the point cloud. If you fly let's say 50 uh meters above uh the rail track on the right you see the uh UAV. What we learned is uh in this case uh that the best uh flight is about 40 mters about uh ground uh level then you need a good uh flight plan of course uh we used a black targets uh which means black and white target um and we have an automatic um detection of the of these control points We used our reprecision and relock and uh the so-called gau targets uh are not well suited for the UAV scanning. Uh so that's a result uh of the point cloud and uh the customer calculated the center line of the rail track and they give back um the feedback that all the values are within plus minus 5 mm for position and heat. So this comes from the customer not from our side. So let's check uh what's terrestal scanning, what's uh kinematic scanning from the air. So this is uh uls unmanned laser scanning. Um so you see um these um areas, but because of the scan uh sw field of view of 100 degree, it stops here. Um and here's the rail track. So the terrestrial scanner was standing here and we scanned uh longer distance with a terrestrial scanner but uh we did not find uh these uh areas. So uh let's go back. This is unmanned laser scanning from the drone and this is terrestal laser scanning from the tripod. This is unmanned laser scanning from the from the UAV. And um an nice point cloud comes from the dressful scanning uh which of of course is slower than uh the UAV. Let's go to the perspective view. So you see the bridge because the UAV is uh on top you cannot see uh underneath. But with a terrestal scanner of course you can also scan the bridge uh from all uh both sides. We change sorry we change uh to a railway station. So the question was how to scan such a railway station in one day. Left side you see the point cloud on the right side the rest laser scanner. The terrestrial laser scanner is called Regal VC 600i. Um, and here you can see that we put uh the RTK GNSS antenna on top of the laser scanner. That means we have a 2 cm uh accuracy of the position. Um, of course the registration is millimeter accurate but the positioning is RTK and of course we are using uh also uh control points. If you look to a Google Earth uh image from half past 7 to 7 p.m. 11 and a half hours, it's a little bit long, but uh in average one uh minute and four uh seconds per scan positions, you see 650 scan positions on one single day. So it looks like uh some smart at the end of the day uh we pressed the button and in the multi uh in the one-touch processing visit after seven to eight hours we saw a point cloud of uh the whole railway station um above and under uh and uh the ground and also um underneath. This is a panorama scan uh from the scan position 385 for example, which uh so the photographs allows you to colorize the point cloud. Um and if you have moving targets uh like uh this lady, she took care about us uh because uh sometimes there are trains with 120 kilometers per hour. Uh we can remove them. So uh if there is a target which is in in only one scan position we remove it because if you have so many scan positions we have also uh a lot of density of the point cloud. So this is the static scan uh 650 scan positions and you can put the scanner also on the backpack with the artic GNSS antenna and we are able uh to use it as kinematic scanning either as backpack or from the car. You can see it on our booth. So you see here uh the combination of static and kinematic scanning. And since this interjeo we are able to co-register uh the kinematic scans uh to the static scan uh the same on uh in the center of the railway station. This is the static scan. Of course we have to remove uh the trains because there are so many trains in 11 and a half hours. Uh but unfortunately we have to remove them um manually. And this is uh the kinematic scan again. Um this is also a new um development. We can uh put the Sony camera on top in order to take uh pictures. Uh the manholes are very important for the uh scanning in the railway station. They they have to be serve it very accurate accurate and you can use all these pictures uh to colorize the point cloud. Uh we are using the Sony camera because it's a global shutter camera.