Self-Supervised Contrastive Representation Learning in Computer Vision

Although its origins date a few decades back, contrastive learning has recently gained popularity due to its achievements in self-supervised learning, especially in computer vision. Supervised learning usually requires a decent amount of labeled data, which is not easy to obtain for many applications. With self-supervised learning, we can use inexpensive unlabeled data and achieve a training on a pretext task. Such a training helps us to learn powerful representations. In most cases, for a downstream task, self-supervised training is fine-tuned with the available amount of labeled data. In this study, we review common pretext and downstream tasks in computer vision and we present the latest self-supervised contrastive learning techniques, which are implemented as Siamese neural networks. Lastly, we present a case study where self-supervised contrastive learning was applied to learn representations of semantic masks of images. Performance was evaluated on an image retrieval task and results reveal that, in accordance with the findings in the literature, fine-tuning the self-supervised training showed the best performance.