767 
Table I. Correlation coefficients between the ground truth data and 
four kinds of image signatures. 
ITEM 
ORIGINAL 
VALUE 
MEAN VALUE 
(3x3 pix) 
NORMALIZED 
VALUE 
RATIO 
(B4/B5) 
TR 
0.752 
0.860 
0.827 
0.301 
SS 
0.572 
0.538 
0.424 
0.193 
CH 
0.846 
0.810 
0.667 
0.681 
TM 
0.547 
0.553 
0.655 
0.681 
OX 
0.502 
0.703 
0.836 
0.524 
LE 
0.773 
0.786 
0.699 
0.251 
RF 
0.705 
0.706 
0.681 
0.277 
PE 
0.845 
0.773 
0.736 
0.589 
UV 
0.817 
0.827 
0.743 
0.715 
PS 
0.803 
0.757 
0.759 
0.747 
CA 
0.448 
0.715 
0.667 
0.129 
MA 
0.567 
0.600 
0.495 
0.309 
CP 
0.684 
0.681 
0.595 
0.579 
MP 
0.250 
0.443 
0.435 
0.273 
TR : Transparency 
SS : Suspended solid concentrations 
CH : Chlorophyll-a 
TM : Water temperature 
OX : Oxygen saturation 
LE : Light energy on the water surface 
RF : Light energy reflected from the water surface 
PE : light energy penetration 
UV : UV extinction 
PS : Acid soluble phosphorus concentrations 
CA : Acid soluble calsium concentrations 
MA : Acid soluble magnesium concentrations 
CP : The ratios of acid soluble calsium and phosphorus 
MP : The ratios of acid soluble magnesium and phosphorus 
: more than 0.8 
Normalized values were calculated 
according to the following equation. 
N J = 
Mi 
X Mi 
X K 
( i=l,2,3,4 ) 
( J=1,2,3,4 ) 
Here, Mi is the mean value of 3x3 pixels 
window of band i, Nj is the normalized 
value, K is a constant, and suffix i 
correspond to band 4, band 5, band 6 and 
band 7. In order to avoid the influence 
of the cloud cover and its shadow in the 
image, ten points of ground truth data 
were eliminated and remaining twenty 
points named 1 to 20 were used for these 
analyses. 
The resulting correlation coefficients 
and some examples of calculattion value 
which were obtained in this study are 
shown in Table I and Table II. As can be 
seen from Table I, nine items of water 
qualites, i. e. TR, CH, OX, LE, RF, PE, UV, 
PS and CA showed sufficient correlations 
to at least one of image signatures. 
Especially, TR, CH and UV had strong 
correlations more than 0.8 to two 
signatures. From this table, following 
results can be deribed. 
1) Mean values of 3x3 pixels window 
showed meaningful correlation 
coefficients more than 0.7 to the 
whole of above nine items. 
2) The general tendency of correlation 
coefficients between original values 
and ground truth data set was the 
same as mean values of 3x3 pixels