SAM LUC
class ; ;
area ratio area ratio
halite(35%)+illite(25%) | 1600 374 1179 275
+carbonate(40%)
halite(35%)+illite(45%)
+carbonate(20%) 34.4 8.0 22.1 32
halite(20%)+illite(40%)
carbonate(40%6) 47.4 11.1 21.0 4.9
cloud 1.6 0.4 0.7 0.2
matshland 26.1 6.1 20.1 4.7
un-classified ISSR - 371 2465 57.6
Table 1. Comparison of SAM and LSU results of Hyperion
image
Camelback
Mountain
anticlinal
Camelback
Mountain
anticlinal
SeBei Gas
Field 2
Legend
P SeBei Gas
i Field 2
Legend
halite(35%)+illite(25%)
+carbonate(40%)
halite(35%)+illite(45%)
#5 — +carbonate(20%) % arbonate(20%)
** halite(20%)+illite(40%) halite(20%)+illite(40%)+c
+carbonate(40%) - arbonate(40%)
, cloud x 5 cloud
"S matshland * matshland
Figure 3. Identification results of alteration minerals with SAM
Figure 4. Identification results of alteration minerals with LUC
E halite(35%)+illite(25%)+c
E arbonate(40%)
halite(35%)+illite(45%)+e
3. METHOD OIL-GAS RESERVOIR DETECTING IN
LIAODONG BAY
3.1 Study Area and Hyperion Image
Submarine topography in Liaodong Bay falls from the top, east
and west side to the centre. The maximum depth of it is 32 m
and the top of the Bay is connected with Liaohe Plain.
Liaodong Bay, the submarine of which is gentle, is great
influenced by the mainland. And lots of rivers pour into it.
What's more, Liaodong Bay is the third biggest oil and gas field
in China. The submarine is rich with oil and gas, which lead to
the significant microseepage. In this paper, four adjacent
Hyperion images were separately obtained in October 2006 and
in May 2007(O Hyperion Image Copyright 2006, 2007). These
images are not only covered with the detected or being
exploited oil-gas fields, but also included with areas which are
serious polluted by land-sourced pollutants in the estuary of
Shuangzi and Daliao River. At last, the reflectance images were
calculated by the methods in Section 2.3
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
3.2 Spectrum Experiment and Analysis of Oil Slick
The experiment was conducted in the tranquil gulf which is
near the estuary of Shuangzi River. The crude oil samples from
Liaodong Bay were selected as experiment material and
FieldSpec-FR was chosen as equipment. In the experiment, tiny
crude oil was dropped into water. Then the oil slick was
diffused from light yellow, yellow and translucent to iridescent
(very thin oil slick). To measure the spectrum of different oil
slick above, FieldSpec-FR was kept with the same angle and
height during the experiment. Finally, the mean value of three
spectrums of each oil slick was calculated.
The result of the spectrums was shown as Figure 5. The
reflectance of water which was covered with oil slick was
higher than that without it. The characteristics were more
obvious in the visible light region (The wavelength is less than
701nm that corresponding to b1-b7 in Hyperion image). When
the wavelength is less than 508nm (corresponding to b6 in
Hyperion image), the reflectance of water which was covered
with oil slick was higher than sea water, while the slope which
was indicated the changing rate was lower. Besides, the
absorption feature was shown gradually in the range of 350nm-
508nm with the decreasing of the oil slick’s thickness. And the
characteristic absorption peaks of oil slick reflectance were not
obvious except in the region of ultraviolet to blue.
It can be found that the available range of wavebands was
mainly in visible range. What's more, the range of wavebands
could be increased to 895nm combining the analysis of the
curves of Hyperion images. In addition, only 47 bands of
Hyperion image can be used in our study because of the non-
calibration bands (Bandl-Band7).
0.14 [75
—
0.12 F ET b-- AverShck
EQ.
010 | j A =: A d
008} 2 4 ;
7 d
0.06 - s | -
- m 4
0.04 F
6.02 -
y ie
N
ud
ac
L
Reflectance
Ai iud. lae Ai d lk dud
0.00 à
400 450 500 550 800 650 700 750 800 850 900 950
Wavelength{nm)
Figure 5. Reflectance of the offshore thin oil slicks
3.3 Extraction of Oil Slick in Liaodong Bay
Water bodies were first isolated from the four scenes Hyperion
images. On this basis, spectral angle mapper (SAM) was used to
extract petroleum hydrocarbon on the sea surface. Then
according to the analysis, differences of spectral characteristics
between water which was covered with oil slick and the one
without it can be reflected on the bands with the central
wavelength of 426nm, 426nm, 457nm, 487nm, 528nm, 569nm,
620nm, 650nm, 701nm, 732nm, 783nm, 813nm, 834nm and
875nm in Hyperion image. Hence, oil slick can be extracted by
the bands and their combinations above.
In the oil slick extraction process, average spectrums of
different oil slick obtained from the experiment were chosen as
reference spectrums. The spectrums above were first resampled
