chien-cheng lee, sz-han chen, hong-ming tsai, pau- choo chung, and yu-chun chiang department of...
TRANSCRIPT
Chien-Cheng Lee, Sz-Han Chen, Hong-Ming Tsai, Pau-Choo Chung, and Yu-Chun Chiang
Department of Communications Engineering, Yuan Ze University Chungli, Taoyuan 320,
Taiwan
IntroductionThe accurate decision rate estimated by
using only simple visual interpretation of liver diseases is around 72%.
In this papperThe diagnosis scheme includes two steps:
features extraction classification
Three kinds of liver diseases are identified: cyst, cavernous hepatomaHemangioma
Features extractionGabor filters have the ability to model the
frequency and orientation sensitivity characteristic of the human visual system.
The features are optimal in the sense of minimizing the joint two-dimensional uncertainty in space and frequency.
2D Gabor filter
Where,
2
22
2 2
yxexp
2
1y , xg
‧ 1j
Frequency: ψOrientation: θBandwidth: σ
θθψ‧θψ sinycosx2jexp y , xgy , xG , ,
2D Gabor filter2-D convolution with image:
),(),(, ,, yxjGyxGyxGWhere IR θψ
yxG R , = θθψ‧ sinycosx2 cos y , xg
yxG I , = θθψ‧ sinycosx2sin y , xg
j i
, , j,iG jy,ixfy,x G θψ‧
The convolution is implemented using the mask of M×M sizes, which M is preferred to be an odd number.
2D Gabor filterEnergy
Minimum Energy
22 ,,,,,,,,, θψθψ yxGyxGyxE IR
22 ,,,,,,,,, θψθψ yxGyxGyxEMin IR
Supervised diseases classificationSupport Vector Machines
Train linear machines with marginsPreprocessing the data to represent patterns in
a high dimension with an appropriate nonlinear mapping Data from two categories can be linearly separable
Find the separating plane with largest margin The larger the margin, the better generalization of
the classifier
SVM
SVMFor linearly separable data set, the optimal
separating hyper-planes can be defined as follows:
where is a subset of the training patterns calledSupport Vectors (SVs).
SVMThe coefficients and b are obtained by
solving the optimization problem:
The parameter C is a regularization parameter selected by the user. C corresponds to assigning a payment to the training errors.
ExperimentThe images is 512 × 512 with contrast media
injection and the graylevel is stored at 12 bits per pixel, include76 liver cysts30 hepatomas 40 cavernous hemangiomas
Result