Checkerboard Targets; Reference Spheres - Faro FOCUS3D X 130 User Manual

®
FARO Laser Scanner Focus
January 2014
• When capturing a chain of scans resulting in a tubular point cloud which is
typical for e.g. tunnel surveying, it is recommended to make use of the
inclination sensor and references with surveyed coordinates. Such references
should be used along the entire chain. The scanner has a certain measuring
uncertainty and if you do not use surveyed references when capturing and
registering a chain of scans, this measuring uncertainty may propagate from
scan to scan.

Checkerboard Targets

• The angle of incidence between the laser beam and checkerboard targets
should not be smaller than 45°.
• Depending on the chosen scanning resolution, the detection of checkerboard
references in the scans by SCENE may get unreliable beyond a certain
distance to the scanner. E.g. when using A4 checkerboard references and
scanning with a resolution of 1/4, the distance to the scanner should not be
greater than 15m. Larger distances can easily be achieved by enlarging the
size of the target or scanning with a higher resolution.
• Checkerboard targets should not be rotated by 45° in relation to the scanner's
axis.
• Have sufficient scan points on the checkerboard targets. They need four or
more scan points per quadrant.
• Checkerboard targets should not be attached to a curved surface.

Reference Spheres

• Reference spheres should be completely visible in the scan. Make sure that
they are not partly covered by other objects.
• Depending on the chosen scanning resolution, the detection of sphere
references in SCENE may get unreliable beyond a certain distance to the
scanner. E.g. when scanning with a resolution of 1/4 and using spheres with
a diameter of 145mm, the distance to the scanner should not be greater than
18m. If you are using larger spheres, e.g. spheres with a diameter of 200mm,
the distance to the scanner may be extended to 45m.
For more information on registering scans and using references for registration,
please see the SCENE manual.
Chapter 5: Getting Started
3D
X 130 Manual
54