1. Self-Supervised Human Activity Recognition by Augmenting Generative Adversarial Networks
- Author
-
Ashish Jaiswal, Ashwin Ramesh Babu, Maria Kyrarini, Fillia Makedon, and Mohammad Zaki Zadeh
- Subjects
FOS: Computer and information sciences ,Discriminator ,Computer science ,business.industry ,Deep learning ,Computer Vision and Pattern Recognition (cs.CV) ,Computer Science - Computer Vision and Pattern Recognition ,Pattern recognition ,02 engineering and technology ,030218 nuclear medicine & medical imaging ,Task (project management) ,Activity recognition ,03 medical and health sciences ,0302 clinical medicine ,Transformation (function) ,Encoding (memory) ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Artificial intelligence ,business ,Representation (mathematics) ,Rotation (mathematics) - Abstract
This article proposes a novel approach for augmenting generative adversarial network (GAN) with a self-supervised task in order to improve its ability for encoding video representations that are useful in downstream tasks such as human activity recognition. In the proposed method, input video frames are randomly transformed by different spatial transformations, such as rotation, translation and shearing or temporal transformations such as shuffling temporal order of frames. Then discriminator is encouraged to predict the applied transformation by introducing an auxiliary loss. Subsequently, results prove superiority of the proposed method over baseline methods for providing a useful representation of videos used in human activity recognition performed on datasets such as KTH, UCF101 and Ball-Drop. Ball-Drop dataset is a specifically designed dataset for measuring executive functions in children through physically and cognitively demanding tasks. Using features from proposed method instead of baseline methods caused the top-1 classification accuracy to increase by more then 4%. Moreover, ablation study was performed to investigate the contribution of different transformations on downstream task.
- Published
- 2020