Title
Cascaded classifier for large-scale data applied to automatic segmentation of articular cartilage
Abstract
Many classification/segmentation tasks in medical imaging are particularly challenging for machine learning algorithms because of the huge amount of training data required to cover biological variability. Learning methods scaling badly in the number of training data points may not be applicable. This may exclude powerful classifiers with good generalization performance such as standard non-linear support vector machines (SVMs). Further, many medical imaging problems have highly imbalanced class populations, because the object to be segmented has only few pixels/voxels compared to the background. This article presents a two-stage classifier for large-scale medical imaging problems. In the first stage, a classifier that is easily trainable on large data sets is employed. The class imbalance is exploited and the classifier is adjusted to correctly detect background with a very high accuracy. Only the comparatively few data points not identified as background are passed to the second stage. Here a powerful classifier with high training time complexity can be employed for making the final decision whether a data point belongs to the object or not. We applied our method to the problem of automatically segmenting tibial articular cartilage from knee MRI scans. We show that by using nearest neighbor (kNN) in the first stage we can reduce the amount of data for training a non-linear SVM in the second stage. The cascaded system achieves better results than the state-of-the-art method relying on a single kNN classifier.
Year
DOI
Venue
2012
10.1117/12.910809
Proceedings of SPIE
Keywords
Field
DocType
large-scale data classification,image segmentation,cascaded classifier,two-stage classifier,support vector machines,osteoarthritis,magnetic resonance imaging (MRI),articular cartilage segmentation
Data set,Image segmentation,Artificial intelligence,Classifier (linguistics),Data point,Computer vision,Pattern recognition,Segmentation,Support vector machine,Margin classifier,Machine learning,Quadratic classifier,Physics
Conference
Volume
ISSN
Citations 
8314
0277-786X
2
PageRank 
References 
Authors
0.39
0
6
Name
Order
Citations
PageRank
Adhish Prasoon11136.43
Christian Igel21841123.54
Marco Loog31796154.31
François Lauze430629.69
Erik Dam51125.75
Mads Nielsen61197156.23