When to use Spheres with Long Range Scanning
At 3D Engineering, we sometimes have projects that involve conducting long range scans of large buildings. Scanning these buildings is more complicated than just placing the scanner in the center of a room and being finished after one scan (unless your building is a single room). You have to consider the complications that come with hallways and corners, which must be worked around. Multiple scans must be taken to accurately align each aspect of the building to each other. While this can be done using a few different methods, one of the most dependable procedures uses white spheres.
White Sphere Scanning Process
This method involves setting up multiple spheres in the area being scanned. Then moving some of the spheres in the direction of the next scan. At least 3 of the spheres must be left in the same location as they were during the previous scan. For example, imagine there are 6 spheres. All 6 spheres are visible in the first scan, and spread around the scan area. For the next scan, spheres 1, 2, and 3 are moved to new locations leaving spheres 4, 5, and 6 in the same location. Once that scan has been done, spheres 1, 2, and 3 are left in their current locations and spheres 4, 5, and 6 are moved to a new location. This process can be repeated as many times as necessary. Using this method, an entire building can be scanned and it can be ensured that all of the individual scans are correctly aligned. It is important to remember that all spheres must be visible in every scan.
Additional Alignment Methods
Other additional methods of alignment include using shapes present in the area (walls or panels are often used as planes) or paper targets can be placed on the walls of the area so that the software can recognize and use them to increase the accuracy of the scan. We will often combine these methods to be sure the scans are aligned accurately.