Autodesk Research

Combining the scans
May 7, 2009

We spent several days setting up for and capturing the scan data for the fifth floor and exterior of 210 King East. Our next task was to combine all of these into a single data set. As mentioned in a previous entry, we posted registration markers around the office. The purpose of these was to provide a common point of reference between the scans that could be aligned in 3D space. This is why we tried to capture at least 3 registrations markers in each scan, which is enough to define a plane in 3D space.

We used Faro Scene to combine the scan data to map the registration markers to each other. This process is interactive: each marker must be highlighted by the user in each individual scan and then manually tagged with the appropriate ID number. The software then automatically calculates the relative 3D offset of each scan to every other. In addition, using the position and elevation information from the survey team, it positions the scans from street level and lobby to those on the fifth floor, effectively positioning all the scans absolutely in 3D world-space.

The software is also able to automatically match unique features within a scan. However, this is most accurate when the features in a scan are very large and distinct. We use this method to align the scans of the exterior of the building.

This map shows where the markers were located in and around the office, as well as the location of the scanner during each scan. Higher resolution versions are available in the download file below.

Here we see the complete dataset of all 53 scans. Since the exterior of the building was scanned from street level, we have no scan of the building's rooftop, so the fifth floor is clearly visible. In the lower image, each individual scan is uniquely color-coded to show how the data from different scans overlap.

Combining The Scans High-Res Images
ZIP - 8.187MB

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