LEAF BOUNDARY EXTRACTION AND GEOMETRIC MODELING OF VEGETABLE SEEDLINGS
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Transcript of LEAF BOUNDARY EXTRACTION AND GEOMETRIC MODELING OF VEGETABLE SEEDLINGS
LEAF BOUNDARY EXTRACTION AND GEOMETRICLEAF BOUNDARY EXTRACTION AND GEOMETRICMODELING OF VEGETABLE SEEDLINGSMODELING OF VEGETABLE SEEDLINGS
Ta-Te Lin, Yud-Tse Chi, Wen-Chi LiaoTa-Te Lin, Yud-Tse Chi, Wen-Chi Liao
Department of Bio-Industrial Mechatronics Engineering,Department of Bio-Industrial Mechatronics Engineering,National Taiwan University,National Taiwan University,
Taipei, Taiwan, ROCTaipei, Taiwan, ROC
INTRODUCTIONINTRODUCTION
Plant growth measurement and Plant growth measurement and modelingmodeling
Image processing techniqueImage processing technique Seedling characteristicsSeedling characteristics ApplicationsApplications
OBJECTIVESOBJECTIVES
To develop image processing algorithms for leaf To develop image processing algorithms for leaf boundary extraction.boundary extraction.
To model leaf boundary with Bezier curves and To model leaf boundary with Bezier curves and develop leaf features based on Bezier curve.develop leaf features based on Bezier curve.
To determined leaf features of selected vegetable To determined leaf features of selected vegetable seedlings based on basic morphological descriptors, seedlings based on basic morphological descriptors, Fourier descriptors, and Bezier curve descriptors.Fourier descriptors, and Bezier curve descriptors.
To examine the variation of leaf features at different To examine the variation of leaf features at different growth stages.growth stages.
To graphically simulate the growth of seedling To graphically simulate the growth of seedling leaves.leaves.
IMAGE PROCESSING ALGORITHMIMAGE PROCESSING ALGORITHM
NoNo
Leaf image acquisitionLeaf image acquisition
Image binarization and blob analysis
Image binarization and blob analysis
Searching leaf tip and base by discontinuity
Searching leaf tip and base by discontinuity
Boundary edge detectionBoundary edge detection
Determination of basic morphological featuresDetermination of basic morphological features
Bezier curve approximationBezier curve approximation
Petiole designationPetiole designation
Error small enough?
Error small enough?
Determination of Bezier featuresDetermination of Bezier features
Determination of Fourier descriptors
Determination of Fourier descriptors
Bezier curve normalizationBezier curve normalization
Yes
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTION
Conventional morphological featuresConventional morphological features Fourier descriptorsFourier descriptors Bezier featuresBezier features
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTION
Basic quantity descriptorsBasic quantity descriptors• Area (A)• Perimeter (P)• Maximum length (L)• Maximum width (W)• Convex hull (H)
Dimensionless shape factorsDimensionless shape factors• Compactness (C)• Roundness (R)• Elongation (E) • Roughness (G)
Conventional Morphological FeaturesConventional Morphological Features
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTIONConventional Morphological FeaturesConventional Morphological Features
2/4 PAC Compactness
Roundness 2/4 LAR
Elongation LWE /Roughness PHG /
Dimensionless shape factorsBasic quantity descriptors
LL
WW
AA
PP HH
1
0
]/2exp[)(1
)(N
k
NukjksN
ua
)()()( kjykxks
x(k) and y(k) are x-y coordinates of leaf boundary pixels
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTIONFourier descriptorsFourier descriptors
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTIONFourier descriptorsFourier descriptors
Steps to extract Fourier descriptorsSteps to extract Fourier descriptorsFind the major axis of seedling leaf
with Hotelling transform
Find the major axis of seedling leaf with Hotelling transform
Rotate seedling leaf to horizontal positionand select 256 points on the leaf boundary
Rotate seedling leaf to horizontal positionand select 256 points on the leaf boundary
Convert x-y coordinates of boundary pointsto complex number
Convert x-y coordinates of boundary pointsto complex number
Use FFT algorithm to obtain Fourier transform coefficient
Use FFT algorithm to obtain Fourier transform coefficient
Normalization of Fourier transform coefficients to obtain Fourier descriptors
Normalization of Fourier transform coefficients to obtain Fourier descriptors
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTIONFourier descriptorsFourier descriptors
Original Image Binary Image
N=256 N=128 N=64 N=32
N=16 N=8 N=4 N=2
CabbageCabbage
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTIONFourier descriptorsFourier descriptors
Original Image Binary Image
N=256 N=128 N=64 N=32
N=16 N=8 N=4 N=2
LettuceLettuce
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTIONBezier descriptorsBezier descriptors
where m = n – 1, xk+1, yk+1 are the coordinates of the n control points, and Bk,m(u) are the Bezier blending coefficients
m
kkmk
m
kkmk
yuBuy
xuBux
01,
01,
)()(
)()(
kmkkmkmk uu
kmk
muumkCuB
)1(
)!(!
!)1(),()(,
P1
P0
P2
P3Bezier curve
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTIONBezier descriptorsBezier descriptors
Steps to obtain Bezier descriptorsSteps to obtain Bezier descriptors
Image acquisition Image segmentation Boundary detection
Finding leaf tip and leaf base
Fitting boundary withBezier curves
Normalization andobtain bezier descriptors
A B C
D E F
LEAF FEATURE EXTRACTIONLEAF FEATURE EXTRACTIONBezier descriptorsBezier descriptors
Bezier descriptorsBezier descriptors• Leaf tip angleLeaf tip angle• Leaf base angleLeaf base angle• Left control line ratioLeft control line ratio• Right control line ratioRight control line ratio• Normalized control Normalized control
point coordinatespoint coordinates
RESULTSRESULTS
Leaf features at different growth stagesLeaf features at different growth stages• Basic morphologic featuresBasic morphologic features• Bezier descriptorsBezier descriptors
ApplicationsApplications• Geometric Modeling of Seedling LeavesGeometric Modeling of Seedling Leaves• Leaf Shape Comparisons and Plant Leaf Shape Comparisons and Plant
IdentificationIdentification
LEAF FEATURES AT DIFFERENT LEAF FEATURES AT DIFFERENT GROWTH STAGESGROWTH STAGES
Cabbage Seedlings
y = 0.5149x + 8.6391
R2 = 0.954
y = 0.4721x + 7.3878
R2 = 0.981
y = 0.1735x + 2.8094
R2 = 0.935
y = 0.1241x + 2.0504
R2 = 0.964
0
5
10
15
20
25
0 5 10 15 20 25 30
Leaf Area (cm2)
Val
ue
(cm
)
Convex hull perimeterPerimeterLengthWidth
Cabbage Seedlings
y = 0.5149x + 8.6391
R2 = 0.954
y = 0.4721x + 7.3878
R2 = 0.981
y = 0.1735x + 2.8094
R2 = 0.935
y = 0.1241x + 2.0504
R2 = 0.964
0
5
10
15
20
25
0 5 10 15 20 25 30
Leaf Area (cm2)
Val
ue
(cm
)
Convex hull perimeterPerimeterLengthWidth
LEAF FEATURES AT DIFFERENT LEAF FEATURES AT DIFFERENT GROWTH STAGESGROWTH STAGES
Cabbage Seedling
y = 0.0011x + 0.8673
R2 = 0.061
y = 0.0027x + 0.6464
R2 = 0.100
y = 0.0016x + 0.6113
R2 = 0.031
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 5 10 15 20 25 30Leaf Area (cm2)
Val
ue
RoundnessRoughnessCompactness
Cabbage Seedling
y = 0.0011x + 0.8673
R2 = 0.061
y = 0.0027x + 0.6464
R2 = 0.100
y = 0.0016x + 0.6113
R2 = 0.031
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 5 10 15 20 25 30Leaf Area (cm2)
Val
ue
RoundnessRoughnessCompactness
LEAF FEATURES AT DIFFERENT LEAF FEATURES AT DIFFERENT GROWTH STAGESGROWTH STAGES
Cabbage Seedling
y = 0.3077x + 96.2
R2 = 0.016
y = 0.3194x + 140.31
R2 = 0.028
0
50
100
150
200
250
0 5 10 15 20 25 30
Leaf Area (cm2)
Deg
ree
Leaf tip angleLeaf base angle
Cabbage Seedling
y = 0.3077x + 96.2
R2 = 0.016
y = 0.3194x + 140.31
R2 = 0.028
0
50
100
150
200
250
0 5 10 15 20 25 30
Leaf Area (cm2)
Deg
ree
Leaf tip angleLeaf base angle
LEAF FEATURES AT DIFFERENT LEAF FEATURES AT DIFFERENT GROWTH STAGESGROWTH STAGES
Cabbage Seedling
y = 0.0004x + 1.3789
R2 = 0.0006
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0 5 10 15 20 25 30Leaf Area (cm2)
Val
ue
Elongation
Cabbage Seedling
y = 0.0004x + 1.3789
R2 = 0.0006
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0 5 10 15 20 25 30Leaf Area (cm2)
Val
ue
Elongation
APPLICATIONSAPPLICATIONSGeometric Modeling of Seedling LeavesGeometric Modeling of Seedling Leaves
Wire Frame Model Perspective View Mapping with Texture
Elliptical ModelElliptical Model
APPLICATIONSAPPLICATIONSGeometric Modeling of Seedling LeavesGeometric Modeling of Seedling Leaves
Wire Frame Model Perspective View Mapping with Texture
Bezier Curve ModelBezier Curve Model
Top ViewTop View
Side ViewSide View
Real ImageReal Image Graphics SimulationGraphics Simulation
APPLICATIONSAPPLICATIONS3D Reconstruction of Seedling Structure3D Reconstruction of Seedling Structure
Graphic Simulation of Cabbage SeedlingGraphic Simulation of Cabbage Seedling
APPLICATIONSAPPLICATIONS3D Reconstruction of Seedling Structure3D Reconstruction of Seedling Structure
Top ViewTop View
Side ViewSide View
Real ImageReal Image Graphics SimulationGraphics Simulation
Graphic Simulation of Chinese Mustard SeedlingGraphic Simulation of Chinese Mustard Seedling
APPLICATIONSAPPLICATIONSLeaf Shape Comparisons and Plant Identification Leaf Shape Comparisons and Plant Identification
LeafFeature
Extraction
LeafFeature
Extraction
Leaf Image
MorphologicalFeatures
FourierDescriptors
BezierFeatures
Pattern Recognition
Statistical AnalysisNeural NetworkCluster Analysis
Genetic Algorithm
Pattern Recognition
Statistical AnalysisNeural NetworkCluster Analysis
Genetic Algorithm
PlantIdentification ApplicationsApplications
APPLICATIONSAPPLICATIONSLeaf Shape Comparisons and Plant Identification Leaf Shape Comparisons and Plant Identification
Chinese Mustard
Chinese Heading Cabbage
Cabbage
Lettuce
APPLICATIONSAPPLICATIONSLeaf Shape Comparisons and Plant Identification Leaf Shape Comparisons and Plant Identification
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.0 0.2 0.4 0.6 0.8 1.0roundness
com
pact
ness
Chinese Heading Cabbage
Lettuce
Cabbage
Chinese Mustard0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.0 0.2 0.4 0.6 0.8 1.0roundness
com
pact
ness
Chinese Heading Cabbage
Lettuce
Cabbage
Chinese Mustard
APPLICATIONSAPPLICATIONS
0
20
40
60
80
100
120
140
160
180
0 20 40 60 80 100 120 140 160 180 200
Leaf Tip Angle (degree)
Leaf
Base
Angle
(D
egre
e)
) Chinese Heading Cabbage
LettuceCabbageChinese Mustard
0
20
40
60
80
100
120
140
160
180
0 20 40 60 80 100 120 140 160 180 200
Leaf Tip Angle (degree)
Leaf
Base
Angle
(D
egre
e)
) Chinese Heading Cabbage
LettuceCabbageChinese Mustard
Leaf Shape Comparisons and Plant Identification Leaf Shape Comparisons and Plant Identification
APPLICATIONSAPPLICATIONSLeaf Shape Comparisons and Plant Identification Leaf Shape Comparisons and Plant Identification
0
1
2
3
4
5
6
0 1 2 3 4 5 6
Left Control Line Ratio
Rig
ht
Contr
ol Lin
e R
atio
)
Chinese Head Cabbage
Lettuce
Cabbage
Chinese Mustard0
1
2
3
4
5
6
0 1 2 3 4 5 6
Left Control Line Ratio
Rig
ht
Contr
ol Lin
e R
atio
)
Chinese Head Cabbage
Lettuce
Cabbage
Chinese Mustard
CONCLUSIONSCONCLUSIONS An image processing algorithm was developed An image processing algorithm was developed
to quantitatively describe vegetable seedling leto quantitatively describe vegetable seedling leaf shape. af shape.
The leaf shape descriptors can be classified intThe leaf shape descriptors can be classified into basic morphological descriptors, Bezier curve o basic morphological descriptors, Bezier curve descriptors, and Fourier descriptors.descriptors, and Fourier descriptors.
The Bezier curve can be successfully used to fiThe Bezier curve can be successfully used to fit the leaf boundary of selected vegetable seedlit the leaf boundary of selected vegetable seedlings. Features deduced from Bezier curves, sucngs. Features deduced from Bezier curves, such as leaf tip angle, leaf base angle, normalized h as leaf tip angle, leaf base angle, normalized control points, and control line ratios, can be uscontrol points, and control line ratios, can be used to characterize leaf shape.ed to characterize leaf shape.
The use of Fourier descriptors to model leaf The use of Fourier descriptors to model leaf shape was demonstrated.shape was demonstrated.
The effect of leaf development on the variation The effect of leaf development on the variation of leaf features was investigated. Leaf features of leaf features was investigated. Leaf features invariant to the leaf size were identified.invariant to the leaf size were identified.
The measured features of seedling leaves The measured features of seedling leaves allowed for 3D reconstruction of the vegetable allowed for 3D reconstruction of the vegetable seedling for graphic display and leaf shape seedling for graphic display and leaf shape comparison.comparison.
CONCLUSIONSCONCLUSIONS
THANK YOUTHANK YOU
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