ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
133 
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range of peak value’s change is correlated with the thickness 
of oil film and the category of oil. Heavy diesel oil’s peak value 
decreases more distinctly than others. Lube and light diesel 
oil's reflectivity will increase as the thickness of oil film adds. 
The amplitude of lube is greater, while the one of light diesel oil 
is little. The peak value change of coal oil is similar to the one 
of heavy diesel oil, but the range of drop of it is not as 
intensive as the one of heavy diesel oil. Crude oil is very 
special. According to spectrum data line of two kinds of crude 
oils that are Middle East crude oil and Daqing crude oil 
selected by experiment. Middle East crude oil that compromise 
little quantity of waxiness has the obvious wet characteristic 
and can form oil film. When this oil film is thin, its reflectivity is 
higher than seawater’s. When oil film becomes thicker its 
reflectivity is lower than seawater’s. While Daqing crude oil 
compromise more quantity of waxiness. It is very mucous, 
easy to agglomerate and close to solid. Its average reflectivity 
is low. 
Considering from the image feature the image hue of heavy 
diesel oil is darker than water’s in channell 2, 3 of TM. 
Information we can get from channel 4, 5, 7 are very little. Hue 
is light in TM6. Lube image has delicacy information in all 
channels; the information is strong in TM3, TM4, TM5, and 
TM7. While in TM1, TM2, TM3 information is delicate and hue 
of image changes from light to dark. The reflectivity of light 
diesel oil is between heavy diesel oil and lubes. Its spectrum 
data line is similar to seawaters’. Only when thickness of oil 
film that is in 0.4 - 0.45 nm is not great there are differences . 
When the thickness of oil film increase it is in 0.45 -0.57 m m. 
Therefore we can get obvious oil film information in TM1, TM2, 
TM3 and CH1, CH2, CH3 from AVHRR. However light diesel 
oil's film thickness has very little influence on its reflectivity. 
3. The Model of Extracting Spilled-oil Information and 
Information Extraction 
By analyzing the spectrum feature of spilled-oil and processing 
image datum, make sure of the hot-spot area of spilled-oil, and 
take synchronous sample from all channels in this area on the 
base of it. The processing is as follows:(fig 1) 
Fig. 1 Information Extracting process 
According to the results of sample analysis form a mode curve 
as practice sample, and then decide if pixels in image accord 
with discriminating condition of a certain set by computer 
program. When original data are transferred to EMS memory, 
program check out every pixel, put the one into a virtual set 
Rnoaa ~ A + YM 
/=1 
and endow with a special value according to a certain 
discriminant. In the end output the result, which is the 
processing of auto-extracting the sea oil information. 
The key problem to extract oil film information on the surface of 
sea by Remote Sensing is to set up the quantificational 
relations between Remote Sensing data and a certain thickness 
of oil film. Based on the result of spectrum feature data line all 
kinds of oil film’ reflectivity feature data line is different from 
each other, but beside data of the reflectivity feature data line 
that is based of the different thickness but the same kind of oil 
film is different. The shape of data line is same basically. So we 
can believe that the thickness of oil film has direct ratio relations 
with reflectivity of oil film, select reflectivity of feature data line of 
a certain thickness of oil film of every kind of oil to multiply a 
certain different coefficient. Then reflectivity of feature data line 
of another thickness of oil film can be obtained. 
Assume that the function value of f(x) in different Point is 
known: f(X1), f(X2) ,f(Xn). We can construct a simple 
multinomial by interpolation.