Deep Learning-Based Automatic Pneumonia Detection System for Medical Imaging: CNN Achieves 96.2% Accuracy

A master's graduation project from Birmingham City University developed a deep learning-based automatic pneumonia detection system for medical imaging using convolutional neural networks (CNN). It achieved a test accuracy of 96.2% in chest X-ray classification tasks, providing an intelligent auxiliary solution for rapid pneumonia diagnosis in areas with scarce medical resources and demonstrating the application potential of artificial intelligence in medical diagnosis.

Pneumonia is one of the leading fatal infectious diseases globally. Traditional chest X-ray diagnosis relies on radiologists' experience, but in areas with scarce medical resources, the shortage of professional physicians leads to delayed diagnosis. Artificial intelligence technology offers a new direction to solve this problem. Based on this demand, this project builds a deep learning medical image classification system focusing on automatic pneumonia detection from chest X-rays.

CNN is used as the core algorithm architecture, following the end-to-end deep learning paradigm. The network structure includes convolutional layers (64, 128, 256 convolution kernels), pooling layers (max pooling), fully connected layers (ReLU activation + 0.5 Dropout), and an output layer (Sigmoid activation). To address limited sample size, data augmentation strategies like random rotation, horizontal flipping, random scaling, and translation are used to enhance the model's generalization ability.

A public chest X-ray dataset is used, divided into 70% training set (≈4100 images), 15% validation set (≈880 images), and 15% test set (≈880 images). The data is annotated by radiologists and anonymized. Training uses the Adam optimizer (learning rate 0.001), batch size 32, 50 training epochs, and input images are uniformly resized to 224×224 pixels.

Validation set accuracy: 90.67%, AUC-ROC: 0.977; Test set accuracy:96.2%, precision:95.7%, recall:94.8%, F1 score:95.2%, AUC-ROC:0.977. Performance outperforms traditional methods like SIFT (70.59%) and LBP (82.35%). The 94.8% recall rate controls missed diagnosis, and the 95.7% precision reduces unnecessary examinations, which has important clinical significance.

Developed based on Python 3.8+, using TensorFlow 2.x/Keras framework, and relying on tools like NumPy and OpenCV. The code is modularly designed, supporting command-line training, single-image inference, Jupyter interactive experiments, and providing pre-trained model weights for direct use.

Only anonymized public datasets are used, and it is stated for academic research only; clinical application requires professional verification and approval. Limitations include model performance depending on training data quality (may decrease for special cases) and the AI system being only an auxiliary tool for doctors, not a replacement for professional diagnosis.

Future directions include extending to more chest disease detection, introducing attention mechanisms to improve interpretability, developing multi-center verification frameworks, exploring privacy protection technologies like federated learning, and helping balance medical resources.