283 
Bare Ground 
    
      
  
  
  
  
"m Edge of The Tree Line 
= 4 
Uu 
© 
= 
cà 
— 
44 
m 
D 
=" 
© 
La 
= 
N 
a 
o 
= 
100 eie PEE EE mn eo ——————— pe 
66 166 266 366 466 566 666 766 866 966 1066 1166 1266 1366 1466 1566 
Measurement Numbers 
Figure 6.An Example of The Ground Surface Line Profile 
4. Summary 
Ye implemented a wide range of experiments through many stages in order to establish a non- 
image, inexpensive and easy-to-use method of measuring cross-sections of the ground. We were 
able to grasp a good understanding of the problems that became clear during each stage as 
well as certain characteristics of the sensor which were not previously known. The result of 
this is the fact that we were able to review our opinion of the suitability of non-prism 
laser-ranger as sensors for obtaining informationon ground surface cross-sections. In other 
words, the points which have been made clear as the characteristics of the non-prism (prism 
not required) laser-ranger are: 
(D Measurement discrepancies are not dependent on the distance. 
@ During practical application, the measurement error of the natural object can be 
contained within a range of approximately 2.5 times the catalog value. (Can be used as 
+50mm if the catalog value is—20mm. ) 
@ There is no effect on measurement accuracy even if the object being measured is a natural 
object. 
(D Identifying precision is approximately 3Üc at a measurement distance of 100m (circle 
with a diameter of approximately 3. 2cm or a rectangle with an area of 5.5cm) We have 
therefore been able to determine that it is suitable for use as a “Profiler” sensor, 
which was the aim of this research. 
5. Problems and Future Considerations 
5-1 Problem of the Platform 
The result of a wide range of experiments induced us to determine that the non-prism laser- 
ranger is the most suitable article for use as an "easy-to-use, inexpensive and safe 
profiler" sensor, which was the aim of this research. However, there remains an unsolved 
problem with the helicopter upon which the sensor is mounted for use as a platform, If the 
sensor is set to measure the distance between the helicopter and the ground with a precision 
level of--50mm, the movement of the helicopter itself renders the measurement values 
meaningless. The fact of the matter is that it is impossible to request a helicopter pilot 
to fly with a precision level of 1m, let alone 50mn. The most expedient way to counteract 
this is to gather data on the accuracy of aerial position time fluctuations and reflect them 
back onto the measurement values. 
IAPRS, Vol. 30, Part 5W1, ISPRS Intercommission Workshop "From Pixels to Sequences", Zurich, March 22-24 1995