Two-Stage COVID19 Classification Using BERT Features

Weijun Tan; Qi Yao; Jingfeng Liu

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arXiv · 2206.14861

Two-Stage COVID19 Classification Using BERT Features

Weijun Tan·Qi Yao·Jingfeng Liu

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Abstract

We propose an automatic COVID1-19 diagnosis framework from lung CT-scan slice images using double BERT feature extraction. In the first BERT feature extraction, A 3D-CNN is first used to extract CNN internal feature maps. Instead of using the global average pooling, a late BERT temporal pooing is used to aggregate the temporal information in these feature maps, followed by a classification layer. This 3D-CNN-BERT classification network is first trained on sampled fixed number of slice images from every original CT scan volume. In the second stage, the 3D-CNN-BERT embedding features are extracted on all slice images of every CT scan volume, and these features are averaged into a fixed number of segments. Then another BERT network is used to aggregate these multiple features into a single feature followed by another classification layer. The classification results of both stages are combined to generate final outputs. On the validation dataset, we achieve macro F1 score of 0.9164.

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Weijun Tan, Qi Yao, Jingfeng Liu. 2022-06-29. Two-Stage COVID19 Classification Using BERT Features. https://arxiv.org/abs/2206.14861

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