phan 2_phan men ecognition 8.pdf

S dng phn mn eCognition cho phn loi nh hng i tng

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PHN II. S DNG PHN MN ECONIGTION 8.0 (eCognition Developper 8.0) CHO

PHN LOI NH HNG I TNG

Chng 1. Phn mn eCognition v Mt s khi nim c bn

Ecognition l phn mn c cung cp v pht trin bi cng ty Definiens AG CHLB c. eCognition c s dng phn tch nh nhiu t l khc nhau t t l rt nh nh cu trc t bo n t l ln nh cc nh v tinh.V d, s dng eCognition phn tch nh ca cc t bo trong y hc, chit tch cc i tng t nh v tinh phc v cho vic quan st, qun l ti nguyn thin nhin v mi trng, phn loi rng.Trong eCognition nh phn tch theo hai con ng: t ng v bn t ng.

Cng ty Definiens cung cp hai b phn mm:

Definiens XD: thit k cho phn tch nh a chiu Definiens Enterprise Image Intelligence : dng cho phn tch nh 2 chiu.

Mt s khi nim c bn s dng trong eCognition

a. i tng nh (Image Object)

Trong x l nh, i tng nh l sn phm ca qu trnh phn mnh nh (segment). Mi

i tng nh l tp hp ca mt nhm Pixel. Mi i tng nh s cha rt nhiu thng

tin. Thng tin v i tng bao gm bn loi: 1) thng tin v c trng ph nh ca i

tng, 2) thng tin v cc yu t hnh thi ca i tng, 3) thng tin v quan h ca i



tng ny vi i tng khc trn nh v 4) thng tin v quan h ca i tng trn nh

vi cc i tng bn ngoi nh ly t cc ngun thng tin khc (bn a hnh, bn

t, bn thu vn v.v.)

b. Phn mnh nh (segmentation)

Phn mnh nh l s chia nh hnh nh thnh cc phn nh (segment) da trn cc tiu

ch: mu sc (color), hnh dng (shape), cht (compactness), trn (smoothness).

S phn mnh to ra cc i tng nh, cc i tng nh ny c gi l cc i tng

nh nguyn thu (i tng nh cha phn loi)

c. Mng phn cp i tng nh

Hnh 1: Mng phn cp i tng nh

Hnh 1 cho thy, mc thp nht c th c ca mt nh chnh l mc pixel v mc cao nht l mc ton nh. Gia hai mc ny bao gi cng tn ti cc i tng cc mc trung gian v mc ny l mc Con (child) ca mc trn n ng thi li l mc



Cha (parent) ca cc i tng mc thp hn. m bo c c mng phn cp s dng cho phn loi th vic phn mnh nh phi tun th cc quy tc sau:

Ranh gii ca i tng mc thp hn phi nm trong ranh gii ca i tng mc cao hn,

Cc tiu ch s dng phn loi i tng mc thp hn phi bao gm cc tiu ch cc mc cao hn ngay trc ,

V phng din thc nghim th mng phn cp to ra cc c s tt cho vic chit xut thng tin khi tn dng c mi quan h to ra t tnh phn cp ny.

d. B quy tc (Rule set)

Trong x l nh, b quy tc bao gm cc tiu ch c thit lp sao cho i tng ny c th tch khi i tng khc trn nh phc v mc ch phn loi.

e. Image Object domain

Hnh 2: Nhm chuyn ca i tng nh (Image Object Domain)

Nhm i tng nh l tp hp cc i tng thuc mt chuyn cc cp c s dng phn loi (Cha, Con, Chu. Cht v.v.). Nhm ln nht chnh l ton b nh; nhm nh nht ch gm mt lp v di n khng cn lp no khc.



Chng 2. S dng phn mn eCognition 8.0

S chung phn loi nh hng i tng

Qu trnh phn loi nh hng i tng trn eCognition c tin hnh theo sau cc bc :

Bc 1: Hin th v qun l d liu

Bc 2: Trn cc knh nh v tng cng cht lng nh

Bc 3: Phn mnh nh v xem cc c trng ca i tng nh

Bc 4: Thit lp ch gii cho phn loi

nh gi kt qu v xut kt qu

Chnh sa kt qu

Thit lp b quy tc v tin hnh phn loi

Phn mnh nh v xem cc c trng ca i tng nh

Thit lp ch gii cc lp phn loi

Hin th v qun l d liu

Trn nh v tng cng cht lng nh



Bc 5: Thit lp quy tc v tin hnh phn loi

Bc 6: Chnh sa kt qu bng tay

Bc 7: nh gi kt qu v xut kt qu

1. Khi ng chng trnh Ecognition 8.0

Click vo Start > Programs> eCognition Developer Trial 8.0> eCognition Developer Trial



Thanh thc n (Menu) bao gm cc Menu sau: File, view, image objects, Analysis, Library, Classification, Process, Tools, Export, Window, Help

1.1. File menu

View

Process Tree Class Hierarchy

Feature View

Image Object Information



Trn Thanh file menu gm mt s cng c chnh thng xuyn s dng:

- Load image file: nhp file nh

- New project: To mt Project mi

- Open project: M mt Project c

- Modify Open project: Thay i Project ang m

1.2. View menu



Thanh view menu gm:

- View setting: m v ng ca s View setting

- Image layer mixing: m v ng cng c trn cc knh nh, tng cng cht lng nh

- Filter classes for dislay: cho php lc cc lp phn loi hin th trn nn nh gc.

1.3. Image objects menu



Image object information: xem cc thng tin i tng nh

Delete level: xo b mt mc i tng nh

1.4. Analysis Builder

1.5. Library men

1.6. Classification menu



Class hierarchy: mng phn cp cc lp phn loi

Legend: ch gii phn loi

1.7. Process menu

Process tree: ca s thit lp b quy tc cho phn tch nh

Load rule set: m b quy tc tn ti

Save rule set: save b quy tc

Delete Rule set: Xo mt b quy tc

1.8. Tools menu

Feature view: ca s quan st cc c trng i tng nh

Manual editting: cng c chnh sa bng tay



1.9. Export menu

1.10. Window menu

1.11. Help menu



Mt s Icon thng xuyn s dng:



2. To mi mt Project, save v m project

- to mi mt project c th lm theo hai cch sau: Cch 1: Trn thanh Menu chn File New project

Cch 2: kch vo biu tng to mi project trn thanh cng c



Sau , Ca s import image layer hin ra, chn nh cn phn tch:

- File name: Donglac_44a_VN2K - File of type: la chn khun dng ca file nh

Tip theo, click open m nh



- Trn ca s creat project cung cp mt s thng tin ca nh nh: h thng to

(coordinate system), phn gii ca nh (Resolution), project size, geocoding, cc knh nh.

- phn tch trn mt phn ca nh bng cch click vo: subset selection trn ca s new project



- save mt project

Vo File save project trn ca s save project t tn project cn lu save



- M mt project Vo file open project chn project cn m



3. Trn cc knh nh v tng cng cht lng nh trn nh: trn thanh thc n chn View Image layer mixing hoc trn thanh cng c

- Trn hp layer mixing, cho php hin th tng layer, nhiu knh nh - Trn hp equalzing, cho php la chn cc cch tng cng nh khc nhau nh:

linear, standard deviation, Gamma correction, Histogram, Manual

Ngoi ra, c th nh trng s cho cc layer ca nh bng cch b du stick trn No weight layer



Thay i trng s ca tng layer bng cch: tch chut tri ln tng knh nh tng trng s, tch chut phi ln tng knh nh gim trng s. Mc ch chnh ca qu trnh trn nh v tng cng cht lng nh gip mt ngi c th nhn bit tt nht i tng trn nh cn chit tch.

4. S dng thut ton Segmentation cho s phn mnh i tng nh

- Trn ca s process tree click chut phi chn Append new



Trn ca s append new, trn hp thut ton Algorithm ko th chn thut ton phn mnh.

eCognition cung cp mt s thut ton cho phn mnh nh (segmentation) nh: Thut ton chessboard segmentation, Thut ton quatree based segmentation, Thut ton multiresolution segmentation

Thut ton phn mnh thng xuyn c s dng trong qu tnh x l nh l phn mnh a phn gii (Multi-segmentation)

Multi-segmentation: p dng mc ti u ho lm gim thiu mc bt ng nht ca i tng nh cho mt phn gii nht nh. Thut ton c th c ng dng trn mc Pixel hay mc i tng nh.

Thut ton c thc hin da theo vic la chn cc trng s v hnh dng (shape), mu sc (color), cht (compactness), trn (smothness) do ngi phn loi la chn (cc trng s ny c th thay i d dng). Nguyn l ca thut ton c trnh by s hnh 3



Hnh 3: S phn mnh theo thut ton multiresolution segmentation



- Level name: t tn cho Level

- image layer weights: t trng s cho tng layer.

- Scale parameter: thay i tham s t l

Tham s t l ( Scale parameter): l vn quan trng trong vic l gii thng tin trn nh v thng c hiu trn c s kch thc pixel.Tham s ny th hin kch thc ca i tng nh trong qu trnh phn mnh.Tham s ny cng ln th kch thc i tng nh to ra cng ln v ngc li.

Sau khi t xong cc tham s, click chut vo Execute thc hin qu trnh phn mnh nh

Hnh 4: Kt qu qu trnh phn mnh nh vi Scale=50, shape=0.2, compactness=0,5

5. To cc lp cho phn loi

Vo Classification class hierarchy

Trong ca s class hierarchy, click chut phi chn insert class thm cc lp



- Name: t tn cho cc class

- La chn mu cho lp



6. Xem c trng ca i tng nh

- y l giai on rt quan trng tm ra ngng (threshold) cho s phn loi cc i tng nh. Mi mt i tng nh c cha nhng thng tin thuc tnh. Cc thng tin thuc tnh ny c th l cc thng tin v gi tr ph ca cc lp, sng, hnh dng, v tr, cu trc, din tch, khong cch n ng bin bn phi, ng bn bn tri ca nh ..

- nhn c trng i tng nh, trn thanh thc n, vo Tools feature view



Trn ca s Feature view chng ta c th xem thng tin ca cc i tng nm trong mt khong gi tr nht nh phc v cho vic xc nh ngng (threshold) phn loi.



Hnh 4: Trn ca s trn tt c cc i tng nh mu Blue l cc i tng nh c gi tr Brighness trong khong [50, 100]).

7. Thit lp thm cc ch s

eCognition cho php thit lp thm cc ch s phc v cho vic nhn bit, phn tch i tng nh.

thit lp thm ch s trn ca s Feature view object features customized

Creat new Arithmetic feature



Ca s customized Feature xut hin:

- Feature name: t tn thut ton

- Feature caculator: thit lp biu thc tnh ch s

- Ok



V d: Tnh ch s tng gi tr xm trung bnh theo TRRI=( DN1+DN2+DN3)/(3*255)

8. Lp b quy tc cho phn loi nh Donglac_44a_VN2K

B nguyn tc s dng trong phn loi i tng bao gm cc thut ton phn mnh nh (segment), cc thut ton phn loi i tng nh, cng nh cc thut ton kim tra thng tin i tng nh, nhp d liu, xut d liu.c thit lp trn ca s Process Tree.

Vic lp mt b rule set trong phn loi nh i tng i hi ngi phn tch nh phi c rt nhiu hiu bit khc nhau nhue: c trng ca tng knh nh, c trng phn x ca i tng trn nh, s hiu bit khu vc nghin cu, mi quan h gia cc i tng vi nhau.



S thit lp phn loi cc i tng trn nh Donglac_44a_VN2K

Chi tit cc bc lp b Rule set cho phn loi nh Donglac_44a_VN2K

- Phn mnh nh ln 1 (segmentaion 1: Tch hai i tng ring bit l Rng v Khng phi rng

- Trong i tng Rng, s dng cc c trng i tng tch thnh cc loi rng khc nhau: Rng 1, Rng 2, Rng 3

t NN (Agri-land)

Mt nc (Sur-water)

t trng Giao

thng (Road)

Th c (Res-land)

Phn mnh nh 2 (Segmentation 2)

Khng phi rng (Non-forest)

Rng 2 (Forest 2)

Phn mnh nh ln 1 (Segmentation 1)

Rng (Forest)

Rng 1 (Forest

Rng 3 (Forest 3)

Nng ry

Cy bi

Phn nh ln 3



- i vi i tng khng phi l Rng, tch nh thnh cc i tng t nng nghip, mt nc, t trng-cy bi, ng giao thng, Th c da theo s phn mnh ln 2 (segmentation 2)

Chi tit cc bc nh sau:

Trong ca s Process tree Click chut phi chn Append new

Name: segment 1



Hnh 5: Kt qu phn mnh nh 1 (segmen1): vi Scale=50, shape=0.1, compactness=0.5

Sau khi phn mnh nh xong, bt u tin hnh phn loi:

Trn process tree nhn chut phi chn Assign class



Trn ca s Edit Process chn Thresold condition xc nh ngng Use class: lp chuyn ok



i tng Rng c phn loi tho mn iu kin ch s DNMT=[0, 0.93]

Cc i tng khng phn loi cn li unclassify thuc vo i tng khng phi l Rng



Kt qu nh c phn loi thnh hai nhm i tng : Rng (forest) v khng phi l Rng (Non-forest).

Dng lnh Merge region gp tt c cc lp khng phi l Rng (non- forest).

tch cc i tng nh trong lp khng phi l rng ta s dng s phn mnh ln 2

( segment 2).



(Kt qu ca qu trnh merge i tng khng phi Rng Non-Forest)



Kt qu ca qu trnh phn mnh ln 2 ( segment 2) trn i tng c chn l Non-forest.

Tip theo, s dng cc c trng ca i tng nh tch cc i tng nh hn (i tng Con).

Trong nhm i tng Rng chia ra lm cc i tng nh hn l Rng 1, Rng 2, Rng 3

Trong nhm i tng khng phi Rng (Non-forest) chia ra lm cc i tng ng giao thng, t th c, t trng cy bi, mt nc, t nng nghip.

B quy tc thit lp:



Kt qu phn loi Rng v ko Rng:



9. Chnh sa bng tay

Cng c Chnh sa bng tay bao gm: gp i tng (Merge Objects Manually), phn loi i tng nh (Classify Image Objects Manually) v chia nh mt i tng nh (Cut an Object Manually) nhn vo cng c chnh sa bng tay:

Vo view Custionmize



Trn ca s customize chn Manual Editting close

Cc cng c ca thanh Manual Editting hin ra

C th ko th hp cng c chnh sa (editting) cho cc i tng nh cha phn loi, v i tng nh c phn loi thnh cc lp chuyn .

1. Cng c la chn (selection) i tng n

2. La chn i tng theo Polygon

3. La chn i tng theo dng ng (line)

4. La chn i tng theo hnh ch nht (Rectangle)

- Gp cc i tng nh:

Tools > Manual Editing > Merge Objects



- Chia nh mt i tng nh (cut an image object)

- Phn loi i tng nh bng tay

Cng c ny cho php phn loi i tng nh thnh cc lp chuyn .

Trn ca s Manual Editting chn: image object editting v hp thoi bn cnh l tn ca lp chng ta mun gn i tng nh thnh lp chuyn .

Sau , Click vo biu tng classify image object phn loi.



10. Xut kt qu

D liu sau khi c phn tch c th c xut ra thnh 3 khun dng chnh: dng vector (Shapefile), dng raster (Raster file) v dng thng k (statistics).

Trn thanh menu: Export export result



- Export type: khun dng d liu s export

- Fomat export

- Level: cc lp phn loi ti mc i tng nh

- Select Classes: la chn cc lp cn export

- Select features: cc c trng s export

- D liu dng Raster



Bng mt s khun dng raster phn mn Ecognition c th xut d liu di dng Raster.

- D liu dng vector (Shapefile)



- D liu dng thng k (Statistics)



Ti liu tham kho

1. http://www.definiens.com/

2. UserGuide and Referencebook ca phn mn eCognition Developper Trial 8.0

phan 2_phan men ecognition 8.pdf

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