CECT: Controllable Ensemble CNN and Transformer for COVID-19 Image Classification

Most computer vision models are developed based on either convolutional neural network (CNN) or transformer, while the former (latter) method captures local (global) features. To relieve model performance limitations due to the lack of global (local) features, we develop a novel classification network CECT by controllable ensemble CNN and transformer. CECT is composed of a convolutional encoder block, a transposed-convolutional decoder block, and a transformer classification block. Different from conventional CNN- or transformer-based methods, our CECT can capture features at both multi-local and global scales. Besides, the contribution of local features at different scales can be controlled with the proposed ensemble coefficients. We evaluate CECT on two public COVID-19 datasets and it outperforms existing state-of-the-art methods on all evaluation metrics. With remarkable feature capture ability, we believe CECT can be extended to other medical image classification scenarios as a diagnosis assistant.