Deep Metric Learning for Cervical Image Classification

Abstract

Cervical cancer is caused by the persistent infection of certain types of the Human Papillomavirus (HPV) and is a leading cause of female mortality particularly in low and middle-income countries (LMIC). Visual inspection of the cervix with acetic acid (VIA) is a commonly used technique in cervical screening. While this technique is inexpensive, clinical assessment is highly subjective, and relatively poor reproducibility has been reported. A deep learning-based algorithm for automatic visual evaluation (AVE) of aceto-whitened cervical images was shown to be effective in detecting confirmed precancer (i.e. direct precursor to invasive cervical cancer). The images were selected from a large longitudinal study conducted by the National Cancer Institute in the Guanacaste province of Costa Rica.The training of AVE used annotation for cervix boundary, and the data scarcity challenge was dealt with manually optimized data augmentation. In contrast, we present a novel approach for cervical precancer detection using a deep metric learning-based (DML) framework which does not incorporate any effort for cervix boundary marking. The DML is an advanced learning strategy that can deal with data scarcity and bias training due to class imbalance data in a better way. Three different widely-used state-of-the-art DML techniques are evaluated-(a) Contrastive loss minimization, (b) N-pair embedding loss minimization, and, (c) Batch-hard loss minimization. Three popular Deep Convolutional Neural Networks (ResNet-50, MobileNet, NasNet) are configured for training with DML to produce class-separated (i.e. linearly separable) image feature descriptors. Finally, a K-Nearest Neighbor (KNN) classifier is trained with the extracted deep features. Both the feature quality and classification performance are quantitatively evaluated on the same data set as used in AVE. It shows that, unlike AVE, without using any data augmentation, the best model produced from our research improves specificity in disease detection without compromising sensitivity. The present research thus paves the way for new research directions for the related field.

Improvement method for cervical cancer detection: A comparative analysis

“…One of the most broadly utilized performance analysis methods is qualitative analysis. Probabilistic statements about the algorithm's performance and weaknesses are based on human visual perception [40,54].…”

An emerging paradigms on cervical cancer screening methods and devices for clinical trails

“…The three most prominent Deep CNNs (ResNet-50, MobileNet, and NasNet) have been configured for training to create linearly separable image feature descriptors in which the collected deep features are used to train a KNN classifier ( 30 ). In Ref.…”

Region of Interest Identification in the Cervical Digital Histology Images

“…We evaluate the DenseNet network for classification as s.s.e/non-SSE RoIs. The scoring metrics include accuracy (ACC), precision (PRC), recall (𝑅𝑅𝑅𝑅), F1-score (𝐹𝐹1) [33]. The overall classification accuracy for both classes is 98%.…”