SentiNet: Mining Visual Sentiment from Scratch

An image is worth a thousand of words for sentiment expression, but the semantic gap between low-level pixels and high-level sentiment make visual sentiment analysis difficult. Our work focuses on two aspects to bridge the gap: (1) Highlevel abstract feature learning for visual sentiment content. (2) Utilizing large-scale unlabeled dataset. We propose a hierarchical structure for automatic discovery of visual sentiment features-we called SentiNet which employed a ConvNet structure. In order to deal with the limitation of labeled data, we leverage the sentiment related signal to pre-annotate unlabeled samples from different source domains. In particular, we propose a hierarchy-stack fine-tune strategy to train SentiNet. We show how this pipeline can be applied on social media visual sentiment analysis. Our experiments on real-world covering half-million unlabeled images and two thousands labeled images show that our method defeats state-of-the-art visual methods, and prove the importance of large scale data and hierarchical architecture for visual sentiment analysis.