1,131 research outputs found
Normalizing Flows for Human Pose Anomaly Detection
Video anomaly detection is an ill-posed problem because it relies on many
parameters such as appearance, pose, camera angle, background, and more. We
distill the problem to anomaly detection of human pose, thus reducing the risk
of nuisance parameters such as appearance affecting the result. Focusing on
pose alone also has the side benefit of reducing bias against distinct minority
groups. Our model works directly on human pose graph sequences and is
exceptionally lightweight ( parameters), capable of running on any
machine able to run the pose estimation with negligible additional resources.
We leverage the highly compact pose representation in a normalizing flows
framework, which we extend to tackle the unique characteristics of
spatio-temporal pose data and show its advantages in this use case. Our
algorithm uses normalizing flows to learn a bijective mapping between the pose
data distribution and a Gaussian distribution, using spatio-temporal graph
convolution blocks. The algorithm is quite general and can handle training data
of only normal examples, as well as a supervised dataset that consists of
labeled normal and abnormal examples. We report state-of-the-art results on two
anomaly detection benchmarks - the unsupervised ShanghaiTech dataset and the
recent supervised UBnormal dataset
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