12. 対象ランドマーク例
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Axial Sagittal Axial Coronal
Fig. 2. Examples of
landmarks with repetitive
shapes. (Left from top) Tips
of the spinal processes of
the 4th, 5th and 6th thoracic
vertebrae. (Right from top)
Tips of the transverse
processes of the 1st, 2nd
and 3rd lumbar vertebrae.
14. ランドマークの初期検出
• ランドマーク毎に独立に検出
• 482の画像特徴量を用いたsliding window法(Nemoto et al.)
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60 local-appearance-model-derived features:
( Principal-component score, residual L2 norm, Mahalanobis distance from the mean)
× Number of eigenvectors used to compose the model subspace (min. 1 to max. 20)
342 Haar features (Tu et al., 2006)
19 types of rectangular solid mask combination
× 9 ROI cube sizes
× 2 preprocessing (original volume or top-hat-filtered with 4 mm kernel radius)
40 Hu-moment features (Prokop and Reeves, 1992)
5 types of moments
× 4 sizes of spherical ROI (2, 4, 6, 8 mm)
× 2 preprocessing (original volume or top-hat-filtered with 4 mm kernel radius)
32 Hessian matrix-derived features
4 types (mean and Gaussian curvatures, shape index, curvedness)
× 4 sizes of Gaussian smoothing σ (2, 4, 6, 8 mm)
× 2 preprocessing (original volume or top-hat-filtered with 4 mm kernel radius)
8 DoG features (Lowe, 2004)
4 pairs of Gaussian smoothers σ: (2,4), (4,6), (6,8), (8, 10) mm
× 2 preprocessing (original volume or top-hat-filtered with 4 mm kernel radius)
Total = 482
15. ランドマーク識別器のstochastic
model
input: 3-D volume 𝑉: ℝ3 → ℝ
output: a set 𝑆 = 𝜃𝑖 where
𝜃𝑖 = 𝐜𝑖, 𝑢𝑖 , 𝑖 = 1,2, … , 𝑆
𝐜𝑖 ∈ ℝ3: candidate position
𝑢𝑖 ∈ ℝ: detector-derived
likelihood
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17. ランドマーク識別器のstochastic
model: multicandidate model
Detector-derived likelihoods:
𝐮 = 𝑢1, 𝑢2, … , 𝑢 𝑆
The probability of each candidate 𝐜 𝑘 being true positive:
𝑝 𝐜 𝑘 ∈ 𝑅𝑡𝑟𝑢𝑒 𝐮 =
1
𝐶
⋅
1 − 𝑝0
𝑆
⋅ 𝑟𝑝𝑟𝑖𝑜𝑟
−1 ⋅
𝑝𝑡𝑟𝑢𝑒(𝑢 𝑘)
1 − 𝑝𝑡𝑟𝑢𝑒(𝑢 𝑘)
The probability of all candidate 𝐜𝑖, ∀𝑖 being false positive:
𝑝 𝐜𝑖 ∉ 𝑅𝑡𝑟𝑢𝑒, ∀𝑖 𝐮 =
1
𝐶
⋅ 𝑝0
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18. Landmark point distribution
model (L-PDM)
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p(X)
mean G
covar. matrix V
)()( GX pp
prior probability distribution
(multiple Gaussian
distribution of G)
*
xm
x1x2
x3
MM
ji
xx
xx
xx
xx
G
1
31
21
Inter-landmark
distance vector
G
19. MAP estimation
2.ランドマーク位置の
事前確率分布
(Based on distances between LMs)
I1 I2 IL
…
1.ランドマーク検出器
3. MAP
推定
ランドマーク位置の最適
組み合わせ
X1 X2 XL
…
X1
X2
X3
X4
ˆ ˆ ˆ
p(X)
I
I|maxargˆ Xx
X
p
xˆ 20/96
20. Proposed two-stage sampling
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1st
sampling
Estimated continuous
distribution
Landmark
detector output
Detector-derived
candidates
Pre-sampled artificial
candidates
Posteriorprobabilitycalculation
Landmark PDM Sampled positions
of other landmarks
Detector-derived candidates
with probabilities
Artificial candidates
with probabilities
Iterative estimation
Sampled
position
2nd
sampling
Two-stage
sampling
algorithm
Iteration
91. 業績一覧(学位論文に使用した
もの)
1. Hanaoka S, Shimizu A, Nemoto M, Nomura Y, Miki S, Yoshikawa T,
Hayashi N, Ohtomo K, Masutani Y. Automatic detection of over 100
anatomical landmarks in medical CT images: a framework with
independent detectors and combinatorial optimization. Medical
Image Analysis 35:192-214. (第2章)
2. Hanaoka S, Masutani Y, Nemoto M, Nomura Y, Miki S, Yoshikawa T,
Hayashi N, Ohtomo K, Shimizu A. Landmark-guided diffeomorphic
demons algorithm and its application to automatic segmentation of
the whole spine and pelvis in CT images. International Journal of
Computer Assisted Radiology and Surgery (accepted). (第4章)
3. Hanaoka S, Nomura Y, Nemoto M, Miki S, Yoshikawa T, Hayashi N,
Ohtomo K, Shimizu A. Fully automatic definition of anatomical
landmarks in medical images: a feasibility study. Int J CARS 11 (Suppl
1):S166-167, 2016. (第3章)
4. Hanaoka S, Nomura Y, Nemoto M, Miki S, Yoshikawa T, Hayashi N,
Ohtomo K, Masutani Y, Shimizu A. HoTPiG: A novel geometrical
feature for vessel morphometry and its application to cerebral
aneurysm detection. Medical Image Computing and Computer-
Assisted Intervention--MICCAI 2015. Springer International
Publishing, 2015. 103-110. (第5章) 95/96
92. 業績一覧(その他)
1. Hanaoka S, Nomura Y, Nemoto M, Masutani Y, Maeda E, Yoshikawa T, Hayashi N, Yoshioka N, Ohtomo K. Automated segmentation method for spinal
column based on a dual elliptic column model and its application for virtual spinal straightening. J Comput Assist Tomogr. 2010 Jan;34(1):156-62.
2. Hanaoka S, Fritscher K, Welk M, Nemoto M, Masutani Y, Hayashi N, Ohtomo K, Schubert R. 3-D graph cut segmentation with Riemannian metrics to avoid
the shrinking problem. Med Image Comput Comput Assist Interv. 2011;14(Pt 3):554-61.
3. Hanaoka S, Fritscher KD, Schuler B, Masutani Y, Hayashi N, Ohtomo K, Schubert R. Whole vertebral bone segmentation method with a statistical intensity-
shape model based approach. Medical Imaging 2011: Image Processing. Proceedings of the SPIE, Volume 7962, pp. 796242-796242-14 (2011).
4. Hanaoka S, Nomura Y, Nemoto M, Masutani Y, Yoshioka N, Yoshikawa T, Maeda E, Hayashi N, Ohtomo K. Automated segmentation method for spinal
column based on parametric model and its application for curved MPR display. Present at Computer Assisted Radiology and Surgery, June 2008. Int J CARS
(2008) 3 (Suppl 1):S398-399.
5. Hanaoka S, Masutani Y, Nomura Y, Nemoto M, Yoshikawa T, Hayashi N, Yoshioka N, Ohtomo K. Vertebral body segmentation algorithm for whole spine CT
images with various pathological changes. Int J CARS (2010) 5 (Suppl 1):S84-86.
6. Hanaoka S, Masutani Y, Nemoto M, Nomura Y, Yoshikawa T, Hayashi N, Ohtomo K. An improved multiple anatomical landmark detection method with
combinatorial optimization and Madaboost-based candidate likelihood determination. Int J CARS (2012) 7 (Suppl 1):S330-331
7. Hanaoka S, Masutani Y, Nemoto M, Nomura Y, Yoshikawa T, Hayashi N, Ohtomo K. Automatic Categorization of Anatomical Landmark-Local Appearances
Based on Diffeomorphic Demons and Spectral Clustering for Constructing Detector Ensembles. Med Image Comput Comput Assist Interv. 2012; (Pt 2):106-
113.
8. Hanaoka S, Nomura Y, Nemoto M, Miki S, Yoshikawa T, Hayashi N, Ohtomo K, Shimizu A. Fully automatic definition of anatomical landmarks in medical
images: a feasibility study. Int J CARS 11 (Suppl 1):S166-167, 2016
9. Hanaoka S, Masutani Y, Nemoto M, Nomura Y, Yoshikawa T, Hayashi N, Yoshioka N, Ohtomo K. Probabilistic Modeling of Landmark Distances and
Structure for Anomaly-proof Landmark Detection. Proceedings of the Third International Workshop on Mathematical Foundations of Computational
Anatomy - Geometrical and Statistical Methods for Modelling Biological Shape Variability (2011) 159-169
10. Hanaoka S, Masutani Y, Nemoto M, Nomura Y, Miki S, Yoshikawa T, Hayashi N, Yoshioka N, Ohtomo K. Sparse Gaussian graphical model estimation for
spatial distribution of multiple anatomical landmarks in the human body - a GPGPU implementation of the graphical lasso algorithm and its application to
automatic landmark detection system. Int J CARS (2013) 8 (Suppl 1):S288-289.
11. Hanaoka S, Masutani Y, Nemoto M, Nomura Y, Miki S, Yoshikawa T, Hayashi N, Yoshioka N, Ohtomo K. Sparse Gaussian graphical model on spatial
distribution of multiple anatomical landmarks – model construction from training datasets with insufficient imaging ranges. Proceedings of the Third
International Workshop on Mathematical Foundations of Computational Anatomy (2013) 107-116.
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