83 research outputs found
Semantic Context Forests for Learning-Based Knee Cartilage Segmentation in 3D MR Images
The automatic segmentation of human knee cartilage from 3D MR images is a
useful yet challenging task due to the thin sheet structure of the cartilage
with diffuse boundaries and inhomogeneous intensities. In this paper, we
present an iterative multi-class learning method to segment the femoral, tibial
and patellar cartilage simultaneously, which effectively exploits the spatial
contextual constraints between bone and cartilage, and also between different
cartilages. First, based on the fact that the cartilage grows in only certain
area of the corresponding bone surface, we extract the distance features of not
only to the surface of the bone, but more informatively, to the densely
registered anatomical landmarks on the bone surface. Second, we introduce a set
of iterative discriminative classifiers that at each iteration, probability
comparison features are constructed from the class confidence maps derived by
previously learned classifiers. These features automatically embed the semantic
context information between different cartilages of interest. Validated on a
total of 176 volumes from the Osteoarthritis Initiative (OAI) dataset, the
proposed approach demonstrates high robustness and accuracy of segmentation in
comparison with existing state-of-the-art MR cartilage segmentation methods.Comment: MICCAI 2013: Workshop on Medical Computer Visio
Recurrent Human Pose Estimation
We propose a novel ConvNet model for predicting 2D human body poses in an
image. The model regresses a heatmap representation for each body keypoint, and
is able to learn and represent both the part appearances and the context of the
part configuration. We make the following three contributions: (i) an
architecture combining a feed forward module with a recurrent module, where the
recurrent module can be run iteratively to improve the performance, (ii) the
model can be trained end-to-end and from scratch, with auxiliary losses
incorporated to improve performance, (iii) we investigate whether keypoint
visibility can also be predicted. The model is evaluated on two benchmark
datasets. The result is a simple architecture that achieves performance on par
with the state of the art, but without the complexity of a graphical model
stage (or layers).Comment: FG 2017, More Info and Demo:
http://www.robots.ox.ac.uk/~vgg/software/keypoint_detection
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