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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004 
  
  
  
Figure 1. Typical Bedsores 
3.1 Existing Methods for Wound Measurement 
Structured Light. An instrument named MAVIS 
"(Figure 2) has been made in the department of 
A 
3 
computer studies, University of Glamorgan, Britain to 
measure arca and volume of wounds based on the 
principal of color coded structured light. This system 
has good performance but is rather too big and 
expensive. 
  
Eb 
Figure 2. MAVIS (Plassmann, 1998) 
Acetate Sheet. The current method of measuring area 
is to place a transparent acetate sheet onto the wound 
and to trace its perimeter. The tracing is then placed 
onto graph paper and the number of squares counted. 
This method is inaccurate and unreliable (Figure 3). 
  
Figure 3. Acetate Sheet 
Saline Injection. The wound is filled with saline 
(Figure 4). The volume dispensed from the syringe 
equals the wound volume. The main source of error is 
that the wound absorbs the saline and it is difficult to 
ensure that the plastic cover takes up the shape of the 
original healthy skin. It is also a contact method so it 
is problematic to the patient. 
  
Figure 4. Saline Injection 
Mould Making. A mould of the wound is made using 
special powders. This is also a painful and infecting 
method. 
Laser Scanning. Laser scanning can be used to 
measure the wounds provided the patient remains still 
during the scan period, which cannot be guaranteed 
for a dynamic object like human body. 
Image Processing. The area of an ulcer is currently 
measured by presenting a human observer with a 
captured video image of a wound, who then uses a 
mouse or pointing device to delineate the wounded 
region. This method is inaccurate and gives only two 
dimensional information. 
MEDPHOS. This system has been designed and 
made in the department of surveying engineering, 
University of Tehran, Iran. It is based on the ideas of 
multi camera  photogrammetry and  projective 
geometry using off-the-shelf components. It can 
effectively provide the physicians and clinicians with 
three dimensional information, measurement and 
reconstruction of the wound surface. Major problems 
related to wound measurement has been considered 
and resolved in the design and production of this 
system. MEDPHOS is an integrated close range 
photogrammetric system for surface reconstruction 
capable of performing almost all kinds of external 
medical measurements specially wound analysis. 
The sections that follow give a brief review of the basic 
components of MEDPHOS. 
4. METHODOLOGY 
Surface reconstruction technology has evolved considerably in 
the last few years. A common characterization subdivides 
different surface reconstruction methods into contact and non- 
contact techniques (Figure 5). An important subclass of the 
latter is optical technology. 
  
Surface Reconstruction 
NE 
L Destructive 
    
      
  
Non-Destructive 
  
[L 
  
  
El f 
CMM ] | Jointed Arms ] Í Slicing | | Non-Optical | 
  
Reflective 
[ 
Non-Contact 
je wal 
—— 
Transmitive 
KT. 
[ optical | | CT ] 
I 
1 
  
— 
| Radar | | Sonar 
| | Passive 
  
I 
| [xw] 
  
  
l MESI te ROLE ] 
| [Shape from Shade | | Interferometry ] | Triangulation | [Depth from Defocus 
em er 
Moire Hologrammetry 
  
Figure 5. Three Dimensional Surface Reconstruction Methods 
313