15MPa(24), 21MPa(27), 21MPa(28), 24MPa(37), 24MPa(37), 
27MPa(38), and 27MPa(37) at 27 days material age which were 
planned by different water/cement ratio(The figures in 
parentheses refer to actual strengthes). 
A field portable spectrometer, GER-3700 had 350nm to 
2500nm in spectral range and 704 in band number. However it's 
demerit is to measure only an object at once because it can 
acquire just point data. 
    
Figure 1. Specrometer GER-3700 
We measured a white reflectance pannel of 99% spectral 
reflectance rate with GER-3700 and considered the 
measurement as reference data and then acquired spectral 
information by measuring concrete specimens respectively. 
  
  
  
Figure 2. Reference data obtained by measuring white 
reflectance panel 
(unit: MPa) 
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 
  
Design Sth 15, Actual Sth 22 Design Strength 15, Actual Strength 22 
    
  
350 550 75% 950 1150135015501 750195602 1502350 
\Wavelength(nm} 
  
  
  
  
  
Figure 3. The example of reflectance curve of concrete 
specimens according to strength depending on different w/c 
Normalization should be performed prior to specimen analysis 
and then it is needed to compare with spectral reflectance of 
airborne or satellite remote sensing data. General concretes 
specimens with different strength and a super high-strength 
specimen were measured by the spectrometer. As a result of 
measuring base planes of the specimens, spectral characteristics 
   
were shown almost similarly on the whole, however they 
appeared different aspect according to the strength in the range 
of 1950nm to 2350nm 
wm Sth:22Map 
Reflectance 
= Super High Sth 
  
Waveiengthirm) 
Figure 4. Spectral reflectance of concretes according to 
compressive strength extracted by spectrometer 
Eight general strength concretes show similar pattern with 
correlation more than 80%, while a super high strength concrete 
which is expressed with the very last legend shows very 
different aspect with general concretes. 
2.2 Extraction of the spectral characteristics from VNIR 
hyperspectral camera 
AisaEagle VNIR hyperspectral camera is 400~970nm in 
spectral range and at maximum 1040 in band number. Spectral 
data collected by a hyperspectral camera as well as a 
spectrometer can be utilized as terrestrial truth data for 
extracting accurate spectral reflectance and furthermore 
analyzing airborne or satellite hyperspectral remote images. 
Spectrometer data as well as VNIR hyperspectral camera 
images are helpful in maintaining concrete-based structures, 
buildings, highways and so forth by means of airborne- or 
satellite-based hyperspectral imagery. In addition, hyperspectral 
data for a variety of concrete objects need to be saved in the 
form of spectral library for rapid and appropriate decision- 
making related to maintenance of concrete structures or 
facilities. 
In this research, we photographed all of 99%, 75% and 2% 
reflectance pannels and the concrete specimens with different 
strengths at 27 days material age to be included in only an 
image using the VNIR camera because target objects are taken 
together with a reflectance pannels for getting accurate 
reference values. 
     
  
Figure 5. VNIR hyperspectral camera