1. Introduction  
2. Datasets  
2.1 DAQUAR (Malinowski and Fritz, 2014)  
2.2 Visual7W (Zhu et al., 2016)  
2.3 Visual Madlibs (Yu et al., 2015)  
2.4 COCO-QA (Ren et al., 2015)  
2.5 FM-IQA (Gao et al., 2015)  
2.6 VQA (Antol et al., 2015)  
3. Models  
3.1 Non-deep Learning Approaches  
3.2 Non-attention Deep Learning Models  
3.3 Attention-based Deep Learning Techniques  
3.4 Other Models  
4. Discussion and Future Work  
5. Conclusion