Ebrahjm, Mostafa Abdel-Bary 
Ten photos for the test field have been taken from different camera positions which arranged to get a complete coverage 
of the test field and to verify a good angle of intersection of the market points. Figure (2) shows the camera positions 
regarding to the test field. Figure (3) shows one of the original used images. 
  
   
  
  
  
Figure (2) The camera positions Figure (3) An original Image 
4.3 Image Enhancement 
No Image enhancement has been used for the different images to assure that the images in all cases are the same and has 
no changes in contrast, brightness, tone adjustment, ... etc., which may effect in the image geometry. 
4.3 The Used Photogrammetric Technique 
A common photogrammetric software has been used to obtain the photogrammetric solution (external and internal 
orientation elements). 371 points have been marked on all photos on the flat ceiling and the dome to obtain the 3-D co- 
ordinates of the marked points and the computer model of the dome and the flat ceiling of the mosque. A self calibration 
for each defined camera has been done through the processing of the project. The points have been marked in a certain 
points on the painting edges. 16 different levels have been chosen in the dome for the purposes of the comparison 
techniques. A coordinates system has been chosen in order to put the model in a symmetrical position regarding to the x 
and y axes in order to make the comparison easier for obtaining the accuracy of the painting. 
The handling of the images happened in the common iterative way through the used photogrammetric software : 
- Approximate marking of the points. 
- Shifting to the exact position in a zoomed window. 
- First processing 
- Moving of single points according to their residual vectors. 
- Second processing. 
- If necessary repeating of the last steps. 
The resulting points' co-ordinates have been written to ASCII file and prepared and formatted for further analytical 
comparison processing. An orthoimage, produced by the used photogrammetric software, has been obtained for the test 
field for further geometric comparison. 
4.4 Results And Comparison 
The results of this investigation are in the form of 3-D co-ordinates and an orthoimage of the test field. In this 
investigation, there are not any given co-ordinates (co-ordinates that obtained from a more accurate procedure) or any 
theoretical way to evaluate a system using its main parameters. So, the standard deviation of the obtained co-ordinates 
will be the accuracy measurement tool. 
The co-ordinates system has been chosen as follows : x and y axes are in the ceiling plan and z axis is the vertical 
direction which is perpendicular to the ceiling plan. 
The evaluation of the different methods was done in two independent ways : 
- Analytical comparison of the measured points 3-D co-ordinates in X, Y, and Z. 
- Geometric comparison of the painting shapes in 2-D co-ordinates (X, Y). 
  
198 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000. 
  
  
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