DeriveNet for (Very) Low Resolution Image Classification.

Abstract

Images captured from a distance often result in (very) low resolution (VLR/LR) region of interest, requiring automated identification. VLR/LR images (or regions of interest) often contain less information content, rendering ineffective feature extraction and classification. To this effect, this research proposes a novel DeriveNet model for VLR/LR classification, which focuses on learning effective class boundaries by utilizing the class-specific domain knowledge. DeriveNet model is jointly trained via two losses: (i) proposed Derived-Margin softmax loss and (ii) the proposed Reconstruction-Center (ReCent) loss. The Derived-Margin softmax loss focuses on learning an effective VLR classifier while explicitly modeling the inter-class variations. The ReCent loss incorporates domain information by learning a HR reconstruction space for approximating the class variations for the VLR/LR samples. It is utilized to derive inter-class margins for the Derived-Margin softmax loss. The DeriveNet model has been trained with a novel Multi-resolution Pyramid based data augmentation which enables the model to learn from varying resolutions during training. Experiments and analysis have been performed on multiple datasets for (i) VLR/LR face recognition, (ii) VLR digit classification, and (iii) VLR/LR face recognition from drone-shot videos. The DeriveNet model achieves state-of-the-art performance across different datasets, thus promoting its utility for several VLR/LR classification tasks.