Jeyapalan, Kandiah 
  
SOFT PHOTOGRAMMETRY 
The videologging system gives the digital image and the X, Y, Z coordinates of the camera locations, using this 
information and soft photogrammetry it is possible to determine the location of any feature. 
Because digital camera used in video logging is a non metric camera, therefore it must be calibrated frequently. The test 
range with road side features, ( fig 10 and table 2), and their coordinates can be used to calibrate the digital camera. 
Video images of the test range from station 0+00, 0+25, and 0+50 were used in Calib [2], which is a simultaneous 
bundle adjustment software that uses collinearity condition (see fig 11 and the model equation). 
Photo 
  
(x, y) 
Z Ground 
x (x Y. zy 
Fig 11. Collinearity 
da (X AX erao(Y -Y )ra(Z-2,.) 
a, (XX Fa -Y)ras(Z —-Z.) 
an(X —X,)+a2(F-—Y,)+an(Z-Z,) 
OX -X ras(Y-Y)trasZ-Z,) 
X,,V,.f -interior orientation elements photo system 
  
X-Xx T6. 10, ——f 
  
y-y 48 +148, =—f 
X, Y,,Z, = camera location in X,Y,Z ground system 
0,,...04, — parameters depending on rotation K,®,@® 
0,0, = radial distortion 
6 06, * decentering distortion... e deii tries equation (1) 
The Calib program simultaneously determines interior and exterior orientation elements as well as ground coordinates 
provided there are enough known parameters and/or observations to make the normal equation non-singular. 
Table 3 shows the results of the calibration. It indicates that the best results are obtained from station 0--50 which is 
closer to the control points suggesting, that the geometric quality deteriorates as the camera moves away from the 
object. The table also shows that single photo can be used to calibrate the camera and multiple photos, in the direction 
of travel, can be used to calibrate as well as locate position of features. 
  
410 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000.