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Table 3 Errors in the projected points over the 
reference plane. 
  
AZ = 100mm 
AZ = 50 mm 
€um oy €vm Ox 
0.382 0.67 0.348 2.99 
0.275 0.63 0.269 2.66 
1.525 0.63 0.853 2.66 
  
simulated image coordinates. The estimated coordinates 
using this intersection approach and the true coordinates, 
which were known from the simulation, were compared. 
The mean-square values for the true errors of the fifteen 
points coordinates are presented in the first and third 
columns of the table 3. The second and third columns 
show the estimated standard deviations for those 
coordinates. These deviations were obtained using 
covariance propagation from the equations (3) 
(Tommaselli et al, 1995). These results can be 
interpreted as the expected accuracy of the range 
system. The mean-square values of the true errors in the 
projected coordinates were similar in the two cases. 
However, in the second one the estimated standard 
deviations were higher, probably due to a worse 
configuration. 
7. CONCLUSION 
All computer software were written in C language, 
including the image processing routines. The obtained 
results with the proposed Photogrammetric Range 
System using simulated data seems to be suitable to the 
proposed applications. Variations in the calibration 
geometry give very accurate results. Feature extraction 
methods were tested and now improvements in the 
algorithms are being introducing in order to obtain higher 
accurate image coordinates. 
The results obtained indicated that 1mm of accuracy in 
height determination and 0.5mm in XY plane can be 
reached, in a typical application. Some questions 
associated with feature extraction must be further 
studied aiming the improvement of the whole accuracy 
of the system. 
7. REFERENCES 
GUISSER, L.; PAYRISSAT, R.; CASTAN, S. A New 3-D 
Measurement System Using Structured Light, IEEE, 
1992. 
MITCHEL, H.L. Applications of digital photogrammetry 
to medical investigations. ISPRS Journal of 
Photogrammetry & Remote Sensing, Vol. 50, N. 3, 
1995. 
TOMMASELLI, A.M.G.; TOZZI, C.L. A recursive 
approach to Space Resection using straight lines. 
Photogrammetric Engineering and Remote Sensing. 
1996. 
TOMMASELLI, A.M.G.; SHIMABUKURO, M.H.; SCALCO, 
P.A.P.; NOGUEIRA, F.M.A. Photogrammetric Range 
373 
System: Mathematical Model and Calibration. In: 
Proceedings of the Third Conference on Optical 3-D 
Measurement Techniques, Viena, 1995. 
TRINDER, J.C.; JANSA,J.; HUANG, Y. An assessment 
of the precision and accuracy of methods of digital 
target location. ISPRS Journal of Photogrammetry 
& Remote Sensing, Vol. 50, N. 2, 1995. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996