Reunion Resort 3D Scanned in 8 Hours
In the Fall of 2019 RIEGL held a 3-day Training Symposium at the Reunion Resort in Orlando, FL. The terrestrial laser scanning segment of the symposium featured the RIEGL VZ-400i laser scanner, featuring automatic on-board registration.
To demonstrate the capabilities of this scanner the team decided to see what they could do to capture the grounds of the Reunion Resort. In eight hours they performed 400 scans with the VZ-400i and registered them in the field. The following is a recap of the project.
Critical elements of the data capture program:
- Utilize IMU tracking to locate and scan in GNSS denied areas
- Conduct on-board simultaneous registration while scanning
- Obtain RGB information at the same time as scanning
- Scan details Panorama_40 [40mdegs] ≡ 7 x 7mm @ 10m
The project began on October 12th, 2019 at 8am in front of the hotel building. No control targets were applied. Georefencing was to WGS84 via on board GNSS receiver. This was later applied to NAD83 via RIEGL’s GeoSys Manager tool.
A coarse scan plan was devised to document the building within the time frame required. It was clear that in order to test the functionality of the on-board sensors the scan plan was to include areas where GNSS was denied – this was achieved by scanning into the underground garage which houses the golf buggies and the cart tunnel under a road way which connects the Watson and Palmer / Nicklaus courses. Additionally, stair areas were included to test the operation of the sensors to the full extent. Scan positions were approximately 10m apart for the most part with a short section at 20m to demonstrate the robust nature of the registration process.
The weather was clear with temperatures at the start of the project approximately 26oC before peaking at approximately 32oC peak in the afternoon. Visibility was clear.
At 40mdegs each scan is completed in 45s. Unique to RIEGL VZ-400i laser scanning systems, the imagery required for the RGB colorization of the point cloud is obtained in parallel with the scanning operation. Imagery for this project was captured with a Nikon D850 DSLR with Nikkor 14mm lens – a familiar configuration to users of RIEGL terrestrial laser scanners.
The whole scanning project was completed just after 8 hours had elapsed, even allowing for comfort breaks! Power was maintained with RIEGL’s new battery pack which is a lithium-ion battery mount allowing up to 3 hot-swappable battery packs to be inserted. The unit can work with a single battery pack – information is displayed on the VZ-400 i touchscreen to advise the operator on battery status for each of the inserted battery packs. 5.5 battery packs were used during this project.
|copy data to laptop||1 hour|
|create RiSCAN project||3 hours (Create LOD)|
|filter (reflectance/deviation)||10 minutes|
|filter (single points)||12 minutes|
On board registration was enabled during the collection. This registration operates discretely in the background on the 2nd of the two processors on the VZ-400i scanner. The progress of the project and the registration was checked regularly with the “VZ-400i project map” app. This enabled the operator to view the registration process and check for any areas of poor coverage, while still in the field, so that sparse or poor detail areas can be rectified, thus avoiding requirements to return to the site for such additions to the survey. This is a registration (not a pre-registration) and does not need data to be streamed to a tablet or laptop – it is carried out entirely within the scanner and is not dependent on light and as demonstrated, can operate independently of any GNSS signal.
The scan project was collected as customers and members went about their normal business in the resort. The project was completed shortly after 4pm.
Total size of the project in the *.PROJ file on the scanner was only 313GB. The following table reveals file sizes for the entire project.
|2019-10-12 REUNION.PROJ||313 GByte on the scanner|
|RiSCAN PRO project||372 Gyte in the PC|
Additional functions required for such a large project are completed quickly within RiScan. Final multi-station adjustment of the scan project to rectify any small propagation errors which became apparent as the project survey loops were closed, took around 1 hour. This resulted in a robust and accurate registered point cloud.
The color indicates the standard deviation of the distance between the scan position. The onboard registration is about 1cm accurate (red color). After the multi-station adjustment 2-3 mm (blue color)
Contact: David Foster, from RIEGL