Asymmetric Anomaly Detection for Human-Robot Interaction

Security in human-robot interaction is the focus of research in this field. Rapid detection of abnormal events that may cause danger in the interaction process can effectively reduce the probability of occurrence of danger. In general anomaly detection methods, 2D or 3D convolutional autoencoders are widely used for anomaly detection. Among them, 2D convolutional autoencoders are with good real-time performance and lower detection accuracy, while 3D convolutional autoencoders are with higher detection accuracy and insufficient real-time performance. In order to ensure realtime performance and obtain higher accuracy, an end-to-end asymmetric convolutional autoencoder network (ACANet) using both 2D and 3D convolutions is designed. Specifically, 3D convolution is used to build the encoder to learn comprehensive information in continuous input frames, and 2D convolution is used to build the decoder to model the information fast, a dimensional alignment module is constructed to connect the encoder and the decoder while avoiding a large number of calculations in the latent space of the 3D features output by the encoder, and the skip connections module is used to obtain accurate predictions. Anomaly detection can then be completed by evaluating the differences between results predicted by the ACANet and real frames. The experimental results show that our method achieves competitive accuracy on mainstream datasets and at the same time obtains the fastest speed. Compared with mainstream methods, this method is more suitable for anomaly detection tasks in human-robot interaction.