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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
3.1 Test 1: synthetic image 
On a base image (figure 1) some changes have been applied: a 
small rotation and a translation to simulate a misregistration, a 
stain and a crack on the wall (figure 2). The histogram of the 
images difference (figure 2 — figure 1) is shown in figure 3: we 
can observe a second peak, due to the dark stain (images have 
been converted in grayscale). The 3D representation of the 
differences is shown in figure 4 (before shift and non maxima 
suppression) and in figure 5 (after shift and non maxima 
suppression). The crack and the stain are detected, along with i z " : SA iem à 
false changes, due to misregistration. SONS 
  
  
  
Figure 3. Histogram of images difference 
  
  
ue E am 
Figure 4. 3D view of images difference 
   
  
  
Figure i. Thobase image Figure 5. 3D view of image difference after radiometric shift 
and non maxima suppression 
  
Figure 2. Image with artificial changes and misregistration Figure 6. The base image of test 2