Research

XDenseQNet

Quantum-enhanced, explainable DenseNet for monkeypox skin lesion classification. Beats every classical baseline tested.

XDenseQNet classifies monkeypox skin lesions across 4 classes on the MSID dataset. The architecture is a DenseNet121 backbone with CBAM attention, feeding a parameterised quantum circuit of 4 qubits and 2 layers as the classification head.

The result outperforms every classical baseline it was compared against, including ConvNeXt-Tiny, EfficientNet-B0, and Swin-Tiny, while running inference in under 10 milliseconds.

Results

Accuracy
95.83%
F1 score
0.9470
Precision
0.9468
Recall
0.9531
ROC-AUC
0.9945
Inference time
9.85 ms

Against classical baselines

  • XDenseQNet: 95.83%
  • ConvNeXt-Tiny: 94.17%
  • EfficientNet-B0: 92.50%
  • MobileNet-V2: 92.50%
  • ResNet50: 90.83%
  • Swin-Tiny: 90.00%
  • ResNet18: 88.33%
  • VGG16: 87.50%

Ablation

Removing the quantum head drops accuracy from 95.83% to 90.00%. Removing both CBAM and the quantum head gives 88.33%. Swapping the head for an SVM with an RBF kernel gives 82.50%. The quantum circuit is doing real work rather than decorating the architecture.

Explainability

The X in the name is the explainability component. The model exposes attention and attribution maps so a prediction can be inspected against the lesion it was made from, which is the minimum bar for anything medical.

Stack

Quantum
PennyLane 0.36+
Deep learning
PyTorch 2.1+DenseNet121CBAM
Data
MSID dataset