This paper presents Uncertainty-aware Contrastive Learning (UCoL): a fully unsupervised framework for discriminative facial representation learning. Our UCoL is built upon a momentum contrastive network, referred to as Dual-path Momentum Network. Specifically, two flows of pairwise contrastive training are conducted simultaneously: one is formed with intra-instance self augmentation, and the other is to identify positive pairs collected by online pairwise prediction. We introduce a novel uncertainty-aware consistency K-nearest neighbors algorithm to generate predicted positive pairs, which enables efficient discriminative learning from large-scale open-world unlabeled data. Experiments show that UCoL significantly improves the baselines of unsupervised models and performs on par with the semi-supervised and supervised face representation learning methods.

Background Several face detection and recognition methods have been proposed in the past decades that have excellent performance. The conventional face recognition pipeline comprises the following: (1) face detection, (2) face alignment, (3) feature extraction, and (4) similarity, which are independent of each other. The separate facial analysis stages lead to redundant model calculations, and are difficult for use in end-to-end training. Methods In this paper, we propose a novel end-to-end trainable convolutional network framework for face detection and recognition, in which a geometric transformation matrix is directly learned to align the faces rather than predicting the facial landmarks. In the training stage, our single CNN model is supervised only by face bounding boxes and personal identities, which are publicly available from WIDER FACE and CASIA-WebFace datasets. Our model is tested on Face Detection Dataset and Benchmark (FDDB) and Labeled Face in the Wild (LFW) datasets. Results The results show 89.24% recall for face detection tasks and 98.63% accuracy for face recognition tasks.