-20- 
Figure 2. Typical 3D-LS image in 3D Parallel Projection 
depth information, the 3D-LSs of INS sample the intensity of 
the backscattered laser light with a 13 bit resolution 
synchronously. This means, the user obtains grey scaled 
3D surface images. Figure 2 shows a typical 3D-LS 
measurement result in 3D-projection. A more detailed 
description of 3D-LS is given in Wehr, 1999. The technical data 
of 3D-LS are compiled in Table 1. 
Table 1. Technical Data of 3D-LS 
2.1 Scanning Patterns 
Figure 1 depicts that 3D-LS uses two galvanometer scanners 
which are mounted orthogonally to each other. This setup 
allows for deflecting the laser beam in two dimensions. In 
standard setup mode the 3D-LS moves the laser beam in 
horizontal line over the object's surface (s. Figure 1). However, 
Figure 3. Digitizing an Object on a Turntable 
control unit respectively, which is 10 arcsec. In this scanning 
mode the user obtains a 3D image of one view. When scanning 
surfaces which are larger than the FOV of 3D-LS, several 
images must be taken in order to obtain a comprehensive data 
set. This means that after scanning, the different views must be 
merged by sophisticated software programs. Taking several 
views is also required if solid volumes, closed interiors, 
surfaces and volumes with undercuts are sampled. Surveying 
procedures and merging will be explained in the preceding 
chapters. 
Figure 4. 3D-LS on Turntable 
frequencies of e.g. 314 MHz resolutions down to the tenth of a 
millimeter are possible. Knowing the actual laser beam's 
orientation for each measurement point, three dimensional 
surface coordinates can be determined (s. Figure 1). Besides the 
using galvanometer scanner drives it is possible to address 
randomly points within the field of view (FOV) which is 
30°x30° for 3D-LS. These drives are controlled by software. 
Therefore, it is possible to adapt the scanning pattern to the 
actual applications. The standard scanning pattern (s. Figure 1), 
the TV line scan, is normally used to digitize object surfaces. 
The number of points along the line and the line spacing is also 
programmable. The minimum spacing is determined by the 
resolution of the galvanometer scanners and the scanning 
optical laser power 
0,5 mW 
optical wavelength 
670 nm 
instantaneous field of 
view IFOV 
0,03° 
(transmitting aperture 3,5 mm) 
total field of view 
FOV 
max. 30°x30° 
receiving aperture 
17 mm 
standard scanning 
2-dim. line scan 
number of pixels 
typ. 200x200, 400x400 or 
800x800 Pixel 
max. range 
<10 m 
slant ranging accuracy 
0,1 mm (for diffuse reflecting 
targets with 60% reflection at 1 m 
distance) 
slant range error 
±1 mm (0 < range < 5 m 
and 50 dB intensity dynamic) 
side tones 
10 MHz and 314 MHz 
sampling rate 
2 kHz (1-side tone), 
800 Hz (2-side tones) 
scanning time for one 
image with 200x200 
pixels 
40 s (2-side tones)