stanbul 2004 
[RED BY 
apability of 
1 includes an 
ed on their 
f the images 
(GRD) was 
pecial object 
nation of the 
3. 
requency and 
s are usually 
y planes that 
and selected 
inted on the 
  
ig the system 
mined using 
   
300 m. 
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part Bl. Istanbul 2004 
GRD [m] 
  
  
100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 
Height [m] 
Graph 4. Ground resolved distance GRD of a 3CCD camera. 
Determination of the spectral resolution 
Spectral resolution, i.e. the range of wavelengths of the electro- 
magnetic spectrum that the sensor is capable of distinguishing 
in a proposed set is determined by the CCD cameras sensitivity 
and the optical filters. 
The NIR range was recorded by means of a monochromatic 
camera with one of the filters B--W 092 or B+W 093. The IR 
sensor sensitivity expressed as the product of the camera 
sensitivity and the filter transmissivity is presented in the 
following graph. 
  
Transmission [75] 
2 
4 
HUN rong 
TANS, 
gay, 
y, 
# 
j 
  
5 
gin 
  
  
350 400 450 500 556 600 650 700 
Wavelength (nm] 
Graph 5. IR sensor sensitivity 
The UV range was recorded by means of a monochromatic 
camera with the set of the filters B+W403 and B+WO081. 
Except for UV radiation, filter B+W403 transmits some NIR 
radiation. To eliminate this, another filter was applied that 
transmits UV radiation and seals off IR. 
Transmission M 
950 1000 1050 
0 500 550 600 650 700 750 800 850 900 
  
Waviength [nm} 
Graph 6. UV sensor sensitivity 
    
SELECTION OF OPTIMUM CHANNELS 
FOR IMAGERY RECORDING 
To select the optimum ranges for imagery recording for the 
specific objects on the defined background, it is necessary to 
make an analysis of the spectral characteristics of reflectivity of 
the object and the background. 
Selection of the spectral range for the study of the spectral 
reflectivity coefficient for selected objects and background was 
determined by the range of spectral sensitivity of the video 
cameras used in the system. 
The study of the spectral reflectivity characteristics was done 
using FieldSpec Open Skies spectroradiometer. 
  
Fig. 7. FieldSpec Open Skies spectroradiometer 
The following graph presents examples of reflectivity 
characteristics for one of the studied fabric samples 
  
— Brown 
         
   
09 Green 
  
Dark-green 
0.8 — — Black | 
— White 
Odbicie [x100%] 
  
  
350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 
Wavelength [nm] 
Graph 8. Spectral reflectivity characteristics for sample 4. 
To determine the camouflage properties of the fabric it is 
necessary to make analysis of the spectral reflectivity 
characteristics of the background against which the fabric 
would be exposed. . 
The differentiation of the object and the background luminance 
is the indispensable condition to detect an object during 
observation. This difference is defined as contrast. 
Te contrast was analyzed on the basis of measurements of the 
spectral reflectivity characteristics of selected study objects and 
various kinds of background.