MEASUREMENT OF HUMAN SKIN COMPRESSION DYNAMICALLY USING AN 
AUTOMATED PHOTOGRAMMETRIC TECHNIQUE 
Gary Robertson 
ShapeQuest Inc. Ottawa, Canada 
gary@ shapecapture.com 
Commission V, WG V/3 
KEY WORDS: 
Automatic target reading, stereo matching, dot target projection, synchronized digital cameras, digital image matching, real time 
measurement, dynamic measurement, human skin, human tissue compression, peripheral vascular disease. 
ABSTRACT: 
This paper describes the procedure used to measure human tissue compression and distortion at a dynamic rate. This is part of an 
ongoing research program on skin tissue and is set up to monitor capillary occlusion especially over areas of boney prominences. 
The monitoring of the skin surfaces allows us to measure the swelling as to the shape of the object applying the pressure. 
Eventually the tissue recovers, and normal capillary flow is restored, the pattern of least pressure recovers first and the most 
pressure recovering last. This whole response is affected by multiple factors, including illness, peripheral vascular disease, and 
heart disease to name a few. This research is also applied to monitor the lapse rate of human skin indention. To meet the demand 
for near real time measurement of this magnitude requires special hardware configurations and software integration and solutions 
in hardware as to provide near real time throughput. The system utilizes multiple synchronized digital cameras with a precision 
pattern projector. The projection system projects a fine mesh of dots on the skin surface and auto point measurement and stereo 
matching are also utilized to measure the surface at near real time rates. 
1. INTRODUCTION 
1.1 Background: 
The following describes the historical research we have 
undertaken over the years regarding skin imprint analysis 
manly in regard to forensic applications. It also describes the 
expanded areas where this research is applied. 
Initially, the work led to procedures used to locate and measure 
imprint or impact marks on skin. This forensic analysis 
covered imprints found on suspects and murder victims. The 
key to impact or imprint mark analysis is the ability to locate 
the mark that in most cases might not be visible to the human 
eye. Several detailed analyses were made including. image 
acquisition techniques utilizing laser or ALS (Alternate Light 
Source) with the digital images. In addition, we implemented a 
procedure using target or pattern generation and automated 
target reading of the imprint to generate a 3D model and x.y.z. 
coordinate data. Also, in this study is digital image matching 
and measurement of the object that made the mark. One of the 
major areas of this study was using pigskin in a comparison for 
developing a database for ante mortem and post-mortem 
marks. This research developed the procedures used to 
precisely (positional accuracy in the micron range) model the 
same imprints on pig and human skin and how close the actual 
relationship is. 
The second phase of the research involved more analysis of 
ante, and post mortem skin imprints including lab controlled 
studies of imprints at the instant of death with sub micron 
accuracy. At this point, we discovered that the lapse rate of 
skin or its dispersion rate back to normality stops at the 
moment of death. We also worked on the characteristics at 
time of death including the analysis of the frozen state of skin 
utilizing pigs. 
We now have a system to measure human tissue compression 
and distortion at a dynamic rate. This is part of our ongoing 
research program on skin tissue and is set up to monitor 
capillary occlusion especially over areas of boney prominences. 
The monitoring of the skin surfaces allows us to measure the 
swelling as to the shape of the object applying the pressure. 
This research follows earlier testing to calculate the elasticity 
and coefficients of human and pig skin, in addition to the 
property analysis of ante-mortem and post mortem imprint 
marks on human and pig skin. This precise modelling of skin 
has opened a new area of research since the ante mortem 
marks can be used to determine time of death calculations from 
the time the imprint was made. 
1.2 Current: 
We are now looking at various responses that would affect the 
lapse rate of skin including drugs, illness, peripheral vascular 
disease, heart disease and also the characteristics of frozen 
skin. The testing of these various conditions gives us a 
comparison of skin lapse rates from normal, that is skin 
imprints from individuals with no medical condition or 
situations where the use of drugs would affect the lapse rate of 
skin. For the first part of the testing we looked at conditions 
that would relate directly to circulation. In this case we studied 
individuals with conditions of CREST and Raynaud's. 
    
   
   
   
  
  
  
  
   
   
  
   
  
   
   
  
   
  
  
  
  
  
  
  
  
    
  
   
  
  
   
   
   
  
  
    
   
  
   
   
   
  
   
  
  
  
  
   
  
  
   
   
  
  
   
   
  
  
  
   
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