Tap chi KHOA HOC OHSP TPHCM S6 51 ndm 2013 PHlTOfNG PHAP PHAN TICH THANH PHAN CHINH TRONG XAC DINH SV PHAN BO KHOANG VAT SET, OXIT SAT BANG Tir LIEU ANH VE TINH LANDSAT TRINH LE HUNG" T 6 M TAT Bdi bd[.]
Trang 1PHlTOfNG PHAP PHAN TICH THANH PHAN CHINH TRONG XAC DINH SV PHAN BO KHOANG VAT SET, OXIT SAT
BANG Tir LIEU ANH VE TINH LANDSAT
TRINH LE HUNG"
T 6 M TAT
Bdi bdo n-inh bdy nghien cdu umg dung phuang phdp phdn tich thdnh phdn chinh trong phdt hien khodng vdt set, khodng vdt axil sdt bdng dii: liiu dnh ve tinh da pho LANDSAT 7 ETM+ Trong bdi bdo cUng sir dung kT thudt Crosta nhdm ldm ndi bgt su tuang phdn giCig ddt set, oxit sit v&i cdc ddi tuong khde tren dnh Kit qud nhdn duac co thi su dung di thdnh lgp bdn ddphdn bd khodng vdt set khodng vdt oxit sdt, phuc vu cong tdc thdm dd, khai thde khodng sdn
Tit khda: vidn thdm, dnh LANDSAT, phuong phdp phdn tich thdnh phdn chinh,
khoang vat set, khoang vat oxit sat
ABSTRACT
The method of analyzing Ihe principal components to deled clay minerals and Iron oxides distribution using images from Landsat satellite
This article presents a study on the application of Ihe method of analyzing the principal components in detecting clay minerals and iron oxides using the multispectral image data from LANDSAT 7 ETM+ This article also uses Crosta technique to highlight the contrast between clay minerals, iron oxides with other objects on the images The results which are obtained in this study can be used lo create a distribution map of clay minerals and iron oxides, and lo serve in mineral mining and exploration
Keywords: remote sensing, LANDSAT image, principal component analysis, clay
mineral, iron oxide
1 Mddiu
Tdi nguydn khodng san Id mgt trong nhOng ngudn tai nguydn quan trgng nhdt ciia mdi qudc gia Khodng sdn Id ngudn nguydn lifu cho rat nhidu ngdnh kinh td nhu san xuit ndng lugng, vdt lieu xdy dung, kim loai, phuc vu cho ndng nghifp, cdng nghidp, Vifc thdm dd, phdt hien cdc md khoang sdn la mdt bdi todn phiic tap vd cip bdeh trong nghien cuu, gidm sat tai nguydn thien nhidn Cae phuang phdp truydn thong dua trdn ket qud didu tra thuc dia chi gidi quydt dugc bdi todn d quy md nhd va rit tdn kem Cdng nghf vidn tham vdi nhiing uu didm vugt trdi nhu didn tich viing phu rdng, cd khd ndng chup lap Iai tai ciing mgt dia didm ttong thoi gian ngin, da dugc sir dung hidu qud trong du dodn, tham dd ede khoang vdt
TS, Hpc ViSn KT thuat QuSn SK, H i Ndi
Trang 2Cho ddn.nay da cd mft sd nghidn ciiu trdn thd gidi vd su dung du lieu anh vidn thdm da phd LANDSAT, Aster trong thanh lap bdn do phan bd mgt sd loai khoang vdt (Abdelsalam et al 2000; Ramadan et al 2001; Madani et ai 2003; Ramadan and Kontny 2004) Trong nghidn ciiu ndy sii dung mdt sd phuang phdp nhu: phuong phap
td hgp mau, phuong phap ti sd anh dd phat hidn cdc viing chua khodng vdt set va oxit sit Cac phuang phdp trdn cd uu didm la rit dan gidn, dd thuc hidn, tuy nhidn dp chinh xdc trong phdt hifn cdc khodng vdt cdn chua cao Cdc nghien cim ndy cung da de cap den vifc iing dung phuang phdp phdn tich thdnh phdn chinh trong xac dinh su phdn bd ciia cdc khoang vat Bai bdo nay phan tich ddc trung phdn xa phd cua khodng vdt set va cac khodng vft chua sdt ddng thdi nghidn ciru ung dung phuong phdp phdn tich thdnh phin chinh trong xdy dung ban dd du bdo vj tri phdn bd ciia cdc khoang vdt trdn
2 Phirong phap nghien cuu
2.1 Bgc trimg phdn xg phd cua khodng vdt set, khoang vgl oxit sdt
Trong ddi sdng nhin thay va hdng ngoai gan (0,4 - I ^m) cac kim ioai chuyen tidp nhu Fe, Mn, Cu, Ni, Cr djc trung bdi su thay ddi muc ndng lugng didn tir Oxit sat bi hip thu phd d ddi sdng ngin bdi hieu iing difn tich Cdc hgp phdn chiia sat bi hdp thu manh nhdt d cdc budc sdng 0,4pm, 0,5pm, 0,7pm, 0,87pm (oxit Fe); Ipm (amphibol, olivin); 0,7pm, 1,8pm (pyroxen) [1]
Khodng chit set gom mdt nhdm cac khodng chdt phyllosilicat (nhdm ngam nudc), thong thudng ed dudng kinh hat nhd ban 2pm Khodng chit set gidu cac oxit vd hidroxit cua sillic, nhdm cung nhu mdt lugng Idn nudc tham gia vdo vifc tao cau tnic
va thay ddi theo timg loai dit set Khoang vft set bi hip thu manh nhdt d ddi sdng can hdng ngo?i (VNIR) do chua nudc, d dai sdng hdng ngoai sdng ngin (SWIR) do chua ion hydroxyl, AL-OH, Mg-OH va d ddi sdng hong ngoai giira (MIR) do chda silicate [1] Dudng cong phdn xa phd ciia mgt sd hgp phin chira sdt (goethite, hematite) va khoang vdt set dugc thd hidn trdn Hinh 1
0 Q
0 6
0 A
0 2
3 0 ° t n i l e /
(MS16n
\ ~
1
\ '
-0 5 1 -0 I S 3 -0 2 5 a o
jifjc sing (;im)
Hmh 1 Duong cong phdn xgphS cua cdc hcrp phdn chua sdt (a), set (b)
149
Trang 3Tap chi KHOA HOC OHSP TPHCIVl
2.2 iTng dung phuong phdp phan lich thdnh phan chinh nghiin ciiu su- phdn bo khodng vgl set, khodng vgl oxit sal
Mdt so phuong phdp ung dung tu lieu dnh vidn tham nghidn ciiu phat hifn khoang vdt set, khoang vdt oxit sdt nhu phuong phdp td hgp mdu, phuong phdp ti sd dnh tuy don gian, dd thuc Men nhung vin cd nhidu nhugc didm Do su tuong quan giOa cdc kdnh dnh id khd Idn, trdn dnh ti sd va anh td hgp mau cd thd nham lin giOa khoang vat va cdc ddi tugng khde Dd gidi quydt vin dd trdn, bdi bao nay nghidn ciiu khd ndng ling dung phuong phdp phdn tich thdnh phin chinh trong phdt hidn khoang vat set, khodng vdt oxit sit bdng dd lieu anh vd tinh LANDSAT 7 ETM+
Phuang phdp phdn tich thanh phin chinh (principal components analys) Id mdt thudt toan ddc trung trong xu Ii dnh vf tinh da phd nhdm Idm ndi bat ddc tinh phd cua mgt sd ddi tugng bd mat Trai Dat (khoang sdn, md Id thidn, ) md cac phuong phdp ndng cao do tuong phan khde khdng nhan bidt rd rdng dugc Ban chdt cua phuong phap phdn tich thdnh phin chinh Id mpt thuat todn thdng kd toan bgc nhdm bidn ddi tap dii lieu da bidn tuang quan vdo ttong mdt tap dO lifu da bidn khdng tuong quan - cdn duge ggi Id cdc thanh phan chinh
Dd phdt hifn khodng vdt set, trong nghidn ciiru sir dung 4 kdnh phd anh LANDSAT 7 ETM+ bao gdm: kdnh I (xanh Iam), kdnh 4 (can hdng ngoji), kdnh 5 (hdng ngoai trung binh), kdnh 7 (hdng ngoai trung binh) dd tinh thdnh phdn chinh Dai sdng xanh luc vd dd (kdnh 2 vd kdnh 3) khdng su dung khi nghidn ciru khodng vat set
dd lo^i bd dnh hudng cua thdm thyc vat [3-7] Gid tri vector ridng va hdm lugng thdng tin chua ttong cac thanh phan chinh (PC) dugc thd hifn trong Bang 1 dudi ddy
Bang 1 Vector rieng vd iuang thong tin trong cdc PC trong phdt hien khodng vdt set
PC
PCI
PC2
PC3
PC4
Vector rieng Kenhl
• 0,354938
0,237907
-0,886691
-0,176627
Kenh 4
0,638399 0,619488 0,367792 0,270939
KenhS
0,609843 -0,511895 0,219110 -0,563953
Kenh 7
0,307498 -0,545524 -0,174637 0,759835
Lu-ong thSng tin trong cac
PC
96,90% 2,02% 1,01% 0,06% Phan tich kdt qua tinh thdnh phin chinh khi nghidn ciru phdt hifn khodng vft set cho thdy, phin ldn lugng thdng tin chiia dung trong thanh phdn chinh thu nhit (PCI -96,90%), hay cd thd xem ring PCI Id hinh anh phan chidu bd mat Thdnh phin chinh thu hai (PC2 - 2,02%) md ta su tuong phan giua dai sdng can hdng ngoji va nhin thiy
O thanh phan chinh thir ba (PC3), thuc vft cd mau tdi, ttong khi d thdnh phin chinh thir
tu (PC4), cdc khodng vdt set cd mau tdi sdm (gia trj vector ridng d kenh 5 Id -0,563953,
d kdnh 7 la +0,759835) De Iam ndi bft khoang vat set trdn anh thanh phdn chinh thii
Trang 4tu, trong nghidn cuu su dung ki thudt tuong phdn mau sic Trdn dnh kit qud, khoang vdt set se cd mdu tring sang (hinh 5a) Phan tich gid tri vector ridng ddi vdi kenh 5 vd kdnh 7 ttong PC3, PC4 cho thdy, gid tti cae vector ridng nay cd ddu ngugc nhau vd cd gid ttj chdnh Ifch nhau khd nhidu, dac bift la d PC4 Trong PC4, gia tti vector ridng d kenh 7 thd hifn su tuong quan "tich cue" manh (+0,759835), trong khi ddi vdi kdnh 5 thd hifn su tuong quan "tidu cue" (-0,563953) Chinh do su tuong phdn ndy, ttong PC4, khodng vdt dugc bidu didn d mau trdng sdng
Tu kdt qud trdn, bdi bdo dua ra md hinh phdt hidn khodng vdt set nhu sau:
Dd lieu anh LANDSAT 7
Tinh thanh phdn chinh (PC)
Kdnh 7
Tang cudng chit lugng anh (tuong phan mau sdc)
Kdt qud phan bd khoang vdt set
Hmh 2 Md hinh phdt hien khodng vdt set tir dir lieu dnh LANDSA T 7 ETM +
Til dfc trung phdn x? phd cua cac hgp phin chua sdt, dd phat hifn khodng vft oxit sit, ttong bdi bdo su dung 4 kdnh phd mang nhidu thdng tin nhit, bao gdm: kdnh 1 (xanh Iam), kdnh 3 (dd), kdnh 4 (can hdng ngoai) vd kdnh 5 (hdng ngoji trung binh) dd linh thdnh phdn chinh Kdt qua tinh vector rieng vd ham lugng thdng tin trong cdc thanh phin chinh khi nghidn ciru phdt hifn khodng vdt oxit sdt dugc thd hidn trong Bdng 2
151
Trang 5Bdng 2 Vector rieng vd luong thong tin trong cdc PC trong phdt
PC
PCI
PC2
PC3
PC4
Vector rieng Kenhl
0,364623
-0,195769
-0,776511
0,475136
Kdnh 3 0,224489 0,252425 -0,460504 -0,820866
Kenh 4 0,654996 -0,640960 0,341079 -0,209319
KenhS 0,622602 0,697944 0,261975 0,237926
hien oxit sdt
Lvong thong tin chira trong cac PC 97,07% 1,54% 1,32% 0,06% Phan tich gid tri vector ridng ddi vdi cac PC cho thdy, PCI cd thd coi la Id hinh dnh phdn chidu bd mat (gia ttj duong cho tit ca cdc kdnh anh), PC2 mang thdng tin vd thuc vat, PC3 ia su tuong phdn giira dai sdng can hdng ngoai va nhin thiy, trong khi d PC4 oxit sat cd mau tdi sdm (vi du ddi vdi kdnh 3, gid tri vector ridng d PC4 la -0,820866, cdn d PCI Id +0,224489) Dd Idm ndi bat oxit sit, tdc gid cung su dung ki thudt tucmg phdn mau sdc Khi dd, trong PC4, oxit sit cd mdu sdng, thuc vft cd mdu toi (Hinh 5b) Md hinh phat hifn khoang vdt oxit sit bdng dii lifu anh LANDSAT 7 ETM+ dugc thd hifn trdn Hinh 3 dudi day
Dii lieu anh LANDSAT 7
Tinh tbdnh phin cbinh (PC)
Kdnh 5
PC4
Tdng cudng chit lugng anh (tuang phan mdu sic)
Kdt qud phan bd khoang vdt oxit sdt
iZZ]
Hmh 3 Md hinh phdt hien oxit sdt tit da lifu dnh LANDSA T7
Trang 6ETM-i-3 Ket qua nghien cmi
Dd minh hga irng dung phuang phap phdn tich thdnh phdn chinh trong phat hifn khodng vat set, khodng vat oxit sit, ttong nghidn cim ndy su dung dnh LANDSAT 7 ETM+ khu vgc tinh Bde Kan (Hinh 4) Anh dugc chup vdo 08-11-2007 la thdi didm miia khd, khdng bj anh hudng cua mdy vd suong mil DQ lieu dnh LANDSAT 7 ETM+
cd dp phan gidi khdng gian 30m d cdc kenh da phd, 60m d kdnh hdng ngoai nhift va 15m d kdnh todn sdc, didn tich phu eda mdt anh la 185 x 185km^ Vdi do phdn gidi khdng gian ttdn, anh LANDSAT 7 ETM+ thich hgp cho cac nghien ciru d quy md cdp tinh va vung
Tinh Bic Kan ndm d ddng bde Bac Bf, cd difn tich tu nhidn 4857,2km^ Bde Kan
la mft tinh gidu tdi nguydn thidn nhidn, ddc bidt Id tdi nguyen khodng san, bao gdm kim loai den, kim Ioai mdu, khodng sdn phi kim Ioai, cdc Ioai dd quy, dd vdi, dit set Hai md ddt set ldn hifn dang dugc khai thac nam d huyfn Bach Thdng (md Khau Ma, Hd Vi)
va huyen Chg Ddn (thugc xd Qudng Bach, Nggc Phdi) Bic Kan ciing Id mdt trong nhiing tinh gidu tdi nguydn sat, vdi cdc md qudng sdt tap trung d cac huydn Chg Ddn, Ngdn Son, Bic Md Hidn nay, tren dja ban tinh dang cd 13 md sdt dugc dua vdo khai thac
Hinh 4 Anh LANDSAT 7 ETM+ chup vdo 08-11-2007 khu vuc Bde Kan
a to hgp mdu 432
153
Trang 7Kdt qua xdc dinh thdnh phdn chinh thii tu nhdm phdt hidn khoang vft set, khoang
vat oxit sit dugc thi hifn ttdn Hinh 5 (a, b) De Iam ndi bat vj tri phan bd cua khodng
vdt set vd oxit sdt, ttong bai bdo su dung kl thuat Crosta nham tang cudng su ttrong
phdn giira cdc khodng vdt ttdn vd cdc ddi ttrgng khde trdn dnh Trong W thudt_ Crosta,
cac dnh kdt qua PC4 trong nghidn cim phat hidn khoang vat set (dnh H), dnh tdng hgp
khodng vat set, oxit sdt (dnh H + F), oxit sit (dnh F) dugc su dgng dd td hgp mdu RGB
theo thu tu tuong dng Anh H+F dugc xac dinh bdng each Idy thdnh phan chinh thu
nhit (PCI) cua td hgp anh H va F nhdm tdch lgc nhiing thdng tin co ban vd-khodng vft
set vd oxit sdt Kdt qud td hgp mau bdng kT thuat Crosta dugc thd hifn ttdn Hinh 6 Trdn
dnh kdt qud nay, cdc pixel anh cd mau xanh nhat Id cac viing chira cd khodng vdt set va
oxit sit, cdc pixel cd mau vdng - da cam thd hidn vung chira nhidu khoang vat set, cdn
cac pixel cd mdu xanh Id cay thd hidn cdc khu vue chua nhieu oxit sat
a) b) Hinh~5 PC4, vimg dnh mdu sdng the Men khodng vdt set (5a), khodng vdt oxit sdt (5b)
Dd xac djnh dp chinh xdc cua phuang phdp phdn tich thanh phin chinh trong phat
hidn khoang vat set, khoang vft oxit sit, trong nghien ciiu su dung ban dd dia chat
-khoang san ti Id 1: 200000 khu vuc tinh Bde Kan ciing nhu cac tai lieu, thdng tin chi
tidt vd cac md khodng sdn ttdn dia ban tinh [7]
Phan tich kdt qua xac djnh su phan bd khodng vat set cho thiy, trii lugng ddt set d
Bde Kan khdng nhidu Cac khu vuc chira nhidu ddt set tap trung d cac huydn Chg Ddn,
Chg Mdi, Bach Thdng va thi xa Bac K^n Cdc viing cd mau vdng - da cam trdn anh
thdnh phan cdng chinh phii hgp vdi cdc md khodng vat set Id thidn ldn trdn dja bdn tinh
Bac Kan nhu md ddt set d xa Nggc Phdi, Qudng Bach (huyfn Chg Ddn), md ddt set d
xa Ha Vj (huyfn Bach Thdng) - hinh 6 Ngoai ra, dit set cdn phdn bd d mgt sd khu vuc
khac: md Bdn Tdc (xd Ddc Vdn, huydn Ngdn San), md dit set d xd Thanh Binh, huyfn
Cho Mdi
Trang 8Trjnh Le HUng
Hmh 6 To hgp mdu RGB (H, H+F, F) Crosta vd kit qud phal hien khodng vdt set
Phan tich kit qua phdt Men khodng vat oxit sit cho thiy.Bdc Kan Id tinh gidu tai nguydn khodng sdn sdt Cdc md qudng sat phan bd d hdu khdp dja bdn tinh Bac Kan, trong dd tap trung nhidu nhit d cdc huyen Chg Ddn, Ba Bd, Bach Thdng, Pac Nam, Na
Ri Trdn td hgp mau Crosta anh thanh phdn chinh cho thiy cdc khu vgc cd mdu xanh la cdy thi hidn vj tri phdn bd khoang vdt oxit sat cung phii hgp vdi vi tri cdc md sdt nhu Lung Vidn (xd Cdc Dan, huyfn Ngan Son), md Bdn Cudn (xd Nggc Phdi, huydn Chg Ddn), md Pu 6 (xd Ddng Lac, huydn Chg Ddn), md Sy Binh (xd Sy Binh, huyfn Bjch Thdng), md Ban Phdng (xa Trung Hda, huydn Ngdn Son), md Qudng Khd (xd Qudng Khd, huydn Ba Bd), (Hinh 7)
Nghidn cua kit qud phat hifn khoang vat set, khodng vat oxit sit khu vuc tinh
Bic Kjn bing dd lieu dnh vd tinh da phd LANDSAT 7 ETM+ cho thiy, phuong phdp phan tich thdnh phan chinh cd thd phdt hifn mdt each nhanh chdng vdi dp chinh xac cao vj tri phan bd cua khoang vdt set, khoang vat oxh sit, ddc bidt Id cac khu vuc md Id thidn Kdt qua nhdn dugc cd y nghia thuc tiin quan trgng, gdp phdn gidm chi phi trong nghidn ciiu ciing nhu cho kdt qud nhanh ttong didu tra, thdm dd khodng san
155
Trang 9Tap chi KHOA HOC DHSP TPHCM
Mo sat
PiiO,
Dong Lac,
Cho D6n
Hmh 7 Vi tri phdn bo khodng vdt oxit sat tren dnh kit qud tS hap mdu Crosta
4 Ket luan
Phdn tich ddc trung phan xa phd cua mot sd loai khoang vat cho thiy dnh vd tinh
da phd dp phdn giai trung binh LANDSAT 7 ETM+ cd thd dugc su dung hidu qua ttong phat hifn va du bao vi tri phdn bd oxit sat, dat set So vdi phuang phap td hgp mdu vd ti sd anh, phuong phdp phan tich thanh phan chinh cd khd ndng phat hifn khoang vdt set vd oxit sat vdi do tin cay dam bao han Kdt qua phdn tich thanh phan chinh cho thdy, dd phat hidn khoang vat set va oxit sat thudng sir dung thanh phdn chinh thu tu Phuang phdp phan tich thdnh phan chinh kdt hgp kT thuat td hgp mdu Crosta cho phep thanh lap ban do khodng vdt sdt, set vdi dd tin cay cao Bdn dd phan
bd khoang chit dugc xay dung cd the dugc su dung hidu qua khi kdt hgp vdi ban dd dia chat va cdc sd lieu didu tra thuc dja trong thdm dd, khai thac mgt sd logi khoang sdn
Trang 10TAI LIEU THAM KHAO
1 Nguyen Van Dai (2002), Casd vien thdm, Nxb Dai hpc Quoc gia Ha Noi
21- Amro F Alasta (2011), "Using remote sensing data to indentify iron deposits in
central western Libya", International conference on Emerging trends in Computer
and Image processing Bangkok, pp.56 - 6 1
3 David M Sherman (1995), "'Electronic spectra of Fe'''^ oxides and oxide hydroxides
in the near IR to near UV", American Mineralogist, Vol 70, pp.1262 - 1269
4 Dematte J.A.M., Fiorio P.R., Ben-Dor E (2009), "Estimation of soil properties by
orbital and laboratory reflectance means and its relation with soil classification", The
open Remote sensing Journal, Vol 2, pp 12 - 23
5 Hankan Mete Dogan (2012), "Mineral composite assessment of Kelkh River Basin
in Turkey by means of remote sensing", Journal Earth System Science 118(6),
pp.701 -710
6 Md Bodruddoza Mia, Yasuhiro Fujimitsu (2012), "Mapping hydrothermal altered mineral deposits using LANDSAT 7 ETM+ image in and around Kuju volcano,
Kyushu, Japan", Journal Earth System Science, 121(4), pp.1049 - 1057
7 www backan.gov vn
(Ng^y Tda so^n nh$n difQC bdi 22-6-2013: ngayphSn bi$n ddnh gid: 10-9-2013,
ngiiycliSp nhSn ddng: 16-10-2013}
157