Paper
24 February 2012 Cascaded classifier for large-scale data applied to automatic segmentation of articular cartilage
Adhish Prasoon, Christian Igel, Marco Loog, François Lauze, Erik Dam, Mads Nielsen
Author Affiliations +
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.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Adhish Prasoon, Christian Igel, Marco Loog, François Lauze, Erik Dam, and Mads Nielsen "Cascaded classifier for large-scale data applied to automatic segmentation of articular cartilage", Proc. SPIE 8314, Medical Imaging 2012: Image Processing, 83144V (24 February 2012); https://doi.org/10.1117/12.910809
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Cited by 4 scholarly publications.
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KEYWORDS
Image segmentation

Cartilage

Magnetic resonance imaging

Medical imaging

Bone

Machine learning

Algorithm development

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