The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008 
would be lost. General serial interface, which is the serial 
interface RS232 of the computer, can not meet the needs of the 
transmitting speed (500k Baud), so it can not transmit the data 
completely and entirely. We insert the Quatech Card into PC 
with PCI slots so that the transmission baud rate can reach 
500k. The rotating platform communicates with the computer 
by RS232.The structure of the portable 3D laser scanner is 
shown in figure 1. 
constant accelerated rotation, its rotation angle is computed as 
follows. 
co = dt 2 (i) 
Here, ¿?is angle acceleration, ¿yis rotation angle, and t is time. 
If the angular velocity is known as v and the accelerated time 
of the rotating platform is known as At, the rotation angle is 
described as follows. 
V 
û)-—t 
At 
2 
(2) 
If the interval between scanlines is At v , and then At = n*At v . By 
testing, «=10, the results are the best. Figure 3 shows the results 
of motion compensation. 
Figure 2 is the 3D laser scanner developed by us, its vertical 
scanline rotates around the z-axis continuously until up to 360°, 
and the scan angle of the vertical scanline can be up to 180°, 
and these scanlines form a closed spherical scan region. 
Figure 3. The results of motion compensation. 
Top: before compensation; Down: after compensation 
Figure 2. The Portable 3D laser scanner prototype system 
Top: The Portable 3D laser scanner prototype; 
Down: The closed spherical scan region. 
2.2 Motion Compensation 
While the rotating platform starting to rotate, before running at 
uniform velocity, there is a short-term accelerated process. 
Supposed the rotating platform starting is considered as 
3. ERROR CORRECTION 
If the sampling resolution vertical scanning is set at 0.25°, then 
every vertical scanline includes 401 points, it spends 45s for a 
yawing scan with 0.25° horizontal resolution. Supposed the 
center of the rotation axis and the center of the mirror wheel of 
the laser scanner are same, then,