International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B3. Istanbul 2004 
e  epipoints: points of line calculated according max and 
min z in object space 
e  Limage :matrix of left image (Base image) 
e Rimage: matrix of right image (Other images) 
e Window size :matrix dimension of a window that 
normalized cross correlation is calculated in it 
And output is : 
s (xi, yi) :best match of point (x,y) on line epipoints 
5.3 OTHER FUNCTIONS 
5.3.4 MAT2CAD 
Matlab image coordinate system is defined as origin at the 
upper left of image and x axis is toward right side of image and 
y axis toward bottom of image as shown in figure 2. 
AutoCad 
  
Figure 2. Matlab and Autocad Coordinate 
System 
When operator zoom and click on images to get image 
coordinate of control points x,y coordinates are in matlab 
coordinate system .to transform these coordinates to autocad 
system ( that origin is bottom left and x axis toward right side 
of image and y axis is toward top of image ) MAT2CAD uses 
x,y coordinates in matlab and get x,y coordinates in autocad 
system. 
5.3.2 CAD2MAT 
This function is reverse of MAT2CAD and transform x,y 
coordinates in Autocad system to matlab image coordinate 
system. This is necessary because FIND MATCH in function 
MULTI MATCH uses coordinates in matlab system. 
5.3.3 FUNCVAL 
This function simply calculates value of a function according 
given parameter names and their values 
534 GET KERNEL 
To evaluate correspondence of two points in two images it is 
needed to calculate correlation coefficient between these two 
points but this is done in a window ie correlation of two 
windows are evaluated for each point on EPIPOINTS 
(explained in FIND MATCH) assuming points are at center of 
windows. To get that portion of image to compute correlation in 
it this function uses following inputs : 
e Image matrix (matrix of grey values of each image 
pixel) 
e (xy): coordinate of center of window 
e window size (in pixel) 
     
and output is a square matrix with size of window size that 
consists grey values of image. this matrix is input for GET 
CORCOEF. 
5.3.5 GET CORCOEF 
After taking matrices of grey values of two windows in left (for 
example base image) and right image it is possible to compute 
normalized cross correlation coefficient for these two windows, 
So the input for this function is windows (matrices) of left 
image and right image candidate points . 
6. SOME EXPERIMENTS 
To test the software , camera Dlink DSC 350F which is a 
simple non-metric digital camera selected , maximum 
resolution of this camera is 640x480 pixels and since sensor 
dimensions are not known all image coordinates used in 
computations are in pixel . to define object space coordinate 
system an object such as a small box almost in size of the 
object choosed or a calibration box prepared . some or all of 
images taken for the object modeling and resulted point clouds 
are shown in following figures : 
6.1 Inner surface of a plate 
  
Figure 3. Images taken in different directions from a plate 
inside calibration object 
  
Figure 4. Resulting point cloud in two different views 
     
   
   
  
   
   
   
    
   
   
   
  
   
    
    
  
  
  
  
   
  
  
  
   
   
  
  
  
  
  
  
  
  
   
  
  
  
   
   
  
    
  
   
   
    
  
  
  
   
   
   
  
  
  
International Arc 
UU ee eel 
6.2 3D model of 
S 
  
Figure 6. Point 
6.3 modeling sui 
Figure 8. One 
lines of egg sui 
from final | 
after filtering g 
The software tes 
cloud in referer 
precision of im 
conjugate points