SATELLITE IMAGE FUSION WITH WAVELET DECOMPOSITION

Transcription

1 SATELLTE MAE FUSON WTH WAVELET DECOMPOSTON Kaa Eşah e-ma: gü Yazga e-ma: stabu Techca Uvesty, Eectca-Eectocs Facuty, Eectocs & Commucato Egeeg Depatmet 80626, Masak, stabu, Tukey Key wods: emote Sesg, Satete Data, mage Fuso, Waveets ASTACT To vefy the featues of a obect o a aea, thee s a eed to mege pachomatc mages wth hgh spata esouto ad mutspecta mages wth hgh specta esouto. Stadad fuso methods ke HS tasfom ae ot satsfactoy, because they dstot specta chaactestcs of the mutspecta data. waveet methods, the am s to decompose the mage to subbads, whch have the ow esouto mage ad deta fomato ad ect the hgh-esouto fomato to the mutspecta mage. ths study, waveet tasfom techque kow as "à tous" agothm s used ad esuts have bee evauated usg SPOT ad S data. Methods based o waveet tasfom gve ceay bette esuts by meas of pesevato of specta chaactestcs.. NTODUCTON The use of satete emote sesg ad ts appcatos have bee mpoved ast a few yeas paae to satete ad compute techoogy. Athough, today's seso systems have hgh esouto magg capabty, they have st costats, because of the obsevato system tsef. Whe data wth hgh spata esouto s oe bad oy, the mutspecta data wth hgh specta esouto has ow spata esouto. Howeve, to vefy the featues of a obect o a aea, esouto both shoud be hgh. So thee s a eed to use data fom dffeet stumets, whch have dffeet popetes. Ths eed bought up the pobem of megg mages wth hgh spata esouto ad hgh specta esouto. The goa s to mege dffeet popetes of mages of same aea ad come up wth a esutg mage havg both. Fo exampe, SPOT povdes hgh-esouto pachomatc data (0m), ad ow esouto mutspecta data (30m). As a esut of the data fuso, hgh-esouto mutspecta mage s acheved. A umbe of methods have bee poposed fo megg pachomatc ad mutspecta data, [,2]. The most commo pocedue s testy-hue-satuato (HS) tasfom method, howeve t causes specta degadato. Ths s patcuay cuca emote sesg f the mages to mege wee ot take at the same tme. the ast few yeas, mut-esouto aayss has become oe of the most pomsg methods fo the aayss of the mages. Sevea authos poposed a ew appoach to the pobem of mage megg, whch uses a mut-esouto aayss pocedue based upo the dscete 2-D waveet tasfom, [-8]. ths study, dffeet fuso methods have bee studed ad the compaso s doe by meas of specta quaty. Waveet-based methods peseve the specta chaactestcs of the mutspecta mage bette tha stadad HS method. To decompose the mage to waveet coeffcets, dscete waveet tasfom agothm kow as "à tous" s used whch aows to use a dyadc waveet wth o-dyadc data a smpe way.. STANDAD MEN METHOD The stadad megg method, HS s based o the coo space tasfomato of to testy-hue-satuato compoets. ock dagam of stadad megg method s gve Fgue. ad the steps to pefom ae the foowg. Fgue. ock dagam of mage fuso wth HS tasfom method.

2 ) egstato of the mutspecta mage to the pachomatc mage wth 0.25 pxes usg goud coto pots. 2) to HS tasfomato 3) Hstogam matchg betwee the pachomatc mage ad the testy compoet of the mutspecta mage to take the dffeeces at the tme of acqusto to accout. ) Chace the testy compoet wth pachomatc mage ad get vese tasfomato back to. Howeve, thee ae dffeet agothms usg dffeet cacuatos fo testy compoet of the HS tasfomato. The defto kow as Smth's tage mode s used ths pape. = () 3. WAVELET DECOMPOSTON Waveet decomposto s beg used wdey fo the pocessg of mages emote sesg. Mutesouto aayss based o the waveet theoy pemts the ecto of deta fomato betwee dffeet eves of scae ad esouto. The decomposto of the mage gves mutpe bads based o the oca fequecy cotet. Waveet tasfom of the mage povdes good ocazato both fequecy ad spata doma. At each decomposto step the esutg mage w have owe esouto. The cotuous waveet tasfom of the sga f(x) s * x b W ( a, b) = f ( x) ψ dx (2) a a whee ψ(x) s the mothe waveet, a s the scae ad b s shft paamete. A. Mutesouto Aayss Mutesouto aayss esuts fom the embedded subsets geeated by tepoatos at dffeet scaes. (2), a s 2 fo ceasg tege vaues of. Fom the fucto, f(x), a adde of appoxmato spaces s costucted wth V V V (3) 3 2 V0 such that, f f(x) V the f(2x) V. The fucto f(x) s poected at each step oto the subset V. Ths poecto s defed by c (k), the scaa poduct of f(x) wth the scag fucto φ(x) whch s dated ad tasated. c ( k ) - - = f ( x ), 2 φ ( 2 x k) (3) Usg the scag fucto, fte coeffcets h() ca be cacuated fom eq. x φ ( ) = h( ) φ( x ) () 2 2. The " à tous" Agothm The dscete waveet tasfom ca be doe wth sevea dffeet agothms. Howeve, ot a agothms ae we suted fo a the pobems. Maat's agothm uses othooma bass, but the tasfom s ot shft-vaat, whch w be a pobem data fuso. To acheve the shft-vaat decomposto, "à tous" agothm s used. t s a edudat tasfom, decmato s ot caed out. The samped data {c o (k)} ae the scaa poducts at pxe k of the fucto f(x), wth a scag fucto φ(x) whch coespods to a ow pass fte. The appoxmato scae, s cacuated wth (5) fom -. c = h( ) c ( k 2 ) (5) w = c ( k) c (6) The waveet paes ae computed as the dffeeces betwee two appoxmato paes usg (6). The dffeece betwee two scaes s the deta fomato betwee two esouto eves. The decomposto usg "à tous" agothm gves waveet paes each havg same umbe of sampes, cayg detas ad a esdua mage wth ow esouto. The ecostucto fomua s ; p 0 k) = c p w = c ( (7) c p(k), s the esdua mage ad w (k) ae the waveet paes fom each scae. f 3 spe s used fo the scag fucto, fte coeffcets cacuated fom () 2-D ae V. MAE FUSON METHODS waveet decomposto, c ae the successve vesos of the oga mage. The fst waveet paes of the hghesouto pachomatc mage have spata fomato that s ot peset the mutspecta mage. The ecto of ths deta fomato to mutspecta mage esuts wth hgh esouto both spata ad specta doma. A. Substtuto of Waveet Paes of (W) Ths method s based o substtutg the fst few waveet paes of pachomatc ad mutspecta mage. So, hghesouto fomato s caed oto the mutspecta mage. Fst thee steps of the pocedue s sma to HS tasfom method. The, PAN mage ad bads of mutspecta mage ae decomposed to waveet paes PAN = w P PAN = (8) (9)

3 = w = = = w = w = (0) The ext step s to epace the fst waveet paes of,, ad decompostos by the paes of pachomatc mage ad pefom the vese waveet tasfom. The bock dagam of the method s Fgue 2. = wp = = wp = = wp = () Fgue 3. mage fuso wth W method Fgue 2. mage fuso wth W method.. Substtuto of Waveet Paes of testy (W) ths method waveet decomposto s apped to the testy compoet of the mutspecta mage stead of, ad (eq.2). The waveet paes of s epaced by the paes of pachomatc mage ad vese tasfom s pefomed (eq.3). The esutg testy compoet, s used tasfomato back to. = w = = wp = The bock dagam of the method s fgue 3. (2) (3) V. APPLCATON AND ESULTS The data used ths study s SPOT-XS mutspecta ad S-C pachomatc data fom 3 Jue 993 ad 22 August 996 espectvey. Whe spata esouto of the SPOT data s 20m, esamped S data s 5m. The test ste coves mosty uba aea ad the apot of stabu. At the ed of the fuso pocess, esutg mutspecta mage has 5m spata esouto, but thee s o data set to compae the esuts. The oy way s to dowsampe both ad use 80m / 20m data to get 20m mutspecta mage, whch ca be compaed to the oga SPOT-XS data. The megg quaty ca be appecated though two ctea, oe s vsua quaty ad the othe s pesevato of the specta chaactestcs. The ehacemet of the spata esouto mutspecta mages shoud ot chace the specta chaactestcs. To evauate the pefomace of the methods, two dces based o coeato coeffcet ad the dex devato ae used. ρ ( L / H ) = δ = MN = M N ( H H )( L 2 ( H H ) = = m= 0 = 0 L( m, ) L) 2 ( L L) H ( m, ) L( m, ) (2) (3) The coeato coeffcet chaactezes the esembace of the two mages, whe the dex devato aows to evauate the specta esdua betwee the meged ad the oga mage. These two mages have the same specta cotet whe the coeato coeffcet s oe ad the dex devato s zeo. The esuts ca be see Fg..

4 (a) (d) (b) (e) (c) Fgue. (a) S PAN (20m) (b) SPOT XS (80m) (c)hs The fst two ae the udesamped pachomatc ad mutspecta mages fom S ad SPOT espectvey. Next thee ae the esuts of dffeet methods, HS, W ad W. The ast oe s the oga mutspecta mage. Fg. shows that the spata esouto s mpoved by megg dffeet mages. The coeato coeffcet ad dex devato esuts ae Fgue5 ad Fgue 6. The coeatos of the waveet-based methods ae hghe (d) W (e) W (f) SPOT XS oga mage (20m) (f) tha the stadad megg agothm wth HS tasfom. Whe waveet decomposto s used o the testy compoet stead of bads, the esuts get bette. Ths meas that W method peseves the specta chaactestcs of the mutspecta mage to a geate extet tha othes. Fo pefect ecostucto of the oga mage, athough the taget woud be a coeato of.0 ad a devato of zeo, S PAN ad SPOT XS

5 data wee acqued dffeet epochs so ths s ot possbe, the coeato vaues ae aoud 0.8, whch s easoabe. Fg 5 ad Fg 6 show that fo each bad f we go fom HS to W method whe the coeato coeffcet of the meged ad the oga mage ceases, dex devato vaue deceases, whch meas specta chaactestcs of the mage s peseved bette. Coeato Coeffcet 0,85 0,8 0,75 0,7 0,65 0,6 S-P & SPOT-XS HS W W Fgue 5. Coeato coeffcet esuts fo thee bads wth HS, W ad W methods. dex Devato 0, 0,2 0, 0,08 0,06 0,0 0,02 0 S-P & SPOT-XS HS W W Fgue 6. dex devato esuts fo HS, W ad W V. CONCLUSON ths pape, some of the techques poposed fo satete mage fuso have bee studed. The vsua quaty of the esuts ae eay same. oth stadad method HS ad the waveet decomposto methods acheved esouto mpovemet. ut fo emote sesg appcatos t s mpotat ot to chace the specta chaactestcs, whe ehacg the spata esouto. W method, whch cossts of extactg deta fomato fom the pachomatc mage by usg waveet decomposto ad combg ths wth the testy compoet of the mutspecta mage; peseves the specta fomato to a bette extet tha the stadad HS method. EFEENCES.. Wech, M. Ehes, Megg Mutesouto SPOT HV ad Ladsat TM Data, Photogammetc Egeeg ad emote Sesg, 53-3,30-303, W.J. Cape, T.M. Lesad,.W. Kefe, The Use of testy - Hue - Satuato Tasfomatos fo Megg SPOT Pachomatc ad Mutspecta mage Data, Photogammetc Egeeg ad emote Sesg, 56-, 59-67, P.S. Chavez, S.C. Sdes, J.A. Adeso, Compaso of Thee Dffeet Methods to Mege Mutesouto ad Mutspecta Data : Ladsat TM ad SPOT Pachomatc, Photogammetc Egeeg ad emote Sesg, 57-3, , Dupot, J. e, J.M. Chassey,. Pautou, The Use of Mutesouto Aayss ad Waveets Tasfom fo Megg SPOT Pachomatc ad Mutspecta mage Data, Photogammetc Eg. ad emote Sesg, 62-9, , T. ach, L. Wad, Seso fuso to mpove the spata esouto of mages : The ASS method, Futue Teds emote Sesg, udmadse, akema, ottedam. 5-5, Aazz, L. Apaoe, F. Aget, S. aot, Waveet ad pyamd techques fo mutseso data fuso : a pefomace compaso vayg wth scae atos, EUOPTO Cofeece o mage ad Sga Pocessg fo emote Sesg V, Foece, tay, Septembe 999, Y. Chba, A. Houace, Coo Space ad Waveet Tasfom fo Megg Mutspecta ad Pachomatc SPOT mages, EUOPTO Cofeece o mage ad Sga Pocessg fo emote Sesg V, Foece, tay, Septembe 999, J. Nuez, X Otazu, O. Fos, A. Pades, V. Paa,. Abo, Mutesouto-ased mage Fuso wth Addtve Waveet Decomposto, EEE Tas. o eoscece ad emote Sesg, 37-3, 20-2, H..Coşku, N.Musaoğu, The use of mutesouto aayss ad HS tasfom fo megg S-C pachomatc ad SPOT-XS mage data aoud stabu, Opeatoa emote Sesg fo Sustaabe Deveopemet, akema, ottedam , J.L. Stack, F. Mutagh, A. aou, mage Pocessg ad Data Aayss, Cambdge Uvesty Pess, Cambdge, Uted Kgdom, M. Vette, J. Kovacevc, Waveets ad Subbad Codg, Petce-Ha c., New Jesey, L. Pasad, S.S. yega, Waveet Aayss wth Appcatos to mage Pocessg, CC Pess, oca ato, K.. Castema, Dgta mage Pocessg, Petce- Ha c., Uppe Sadde ve, K. Esah, Methods of Megg Dffeet Satete mages to mpove esouto, MSc. Thess, İ.T.Ü. sttute of Scece ad Techoogy, 200.