Semantic Feature Augmentation in Few-shot Learning
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A fundamental problem with few-shot learning is the scarcity of data in training. A natural solution to alleviate this scarcity is to augment the existing images for each training class. However, directly augmenting samples in image space may not necessarily, nor sufficiently, explore the intra-class variation. To this end, we propose to directly synthesize instance features by leveraging the semantics of each class. Essentially, a novel auto-encoder network dual TriNet, is proposed for feature augmentation. The encoder TriNet projects multi-layer visual features of deep CNNs into the semantic space. In this space, data augmentation is induced, and the augmented instance representation is projected back into the image feature spaces by the decoder TriNet. Two data argumentation strategies in the semantic space are explored; notably these seemingly simple augmentations in semantic space result in complex augmented feature distributions in the image feature space, resulting in substantially better performance. The code and models of our paper will be published on: https://github.com/tankche1/Semantic-Feature-Augmentation-in-Few-shot-Learning.
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