Deep learning approaches to building rooftop thermal bridge detection from aerial images

Thermal bridges are weak points of building envelopes that can lead to energy losses, collection of moisture, and formation of mould in the building fabric. To detect thermal bridges of large building stocks, drones with thermographic cameras can be used. As the manual analysis of comprehensive image datasets is very time-consuming, we investigate deep learning approaches for its automation. For this, we focus on thermal bridges on building rooftops recorded in panorama drone images from our updated dataset of Thermal Bridges on Building Rooftops (TBBRv2), containing 926 images with 6,927 annotations. The images include RGB, thermal, and height information. We compare state-of-the-art models with and without pretraining from five different neural network architectures: MaskRCNN R50, Swin-T transformer, TridentNet, FSAF, and a MaskRCNN R18 baseline. We find promising results, especially for pretrained models, scoring an Average Recall above 50% for detecting large thermal bridges with a pretrained Swin-T Transformer model.

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Datasets


Results from the Paper


Task Dataset Model Metric Name Metric Value Global Rank Benchmark
Object Detection TBBR Swin-T (ImageNet-1k pretrain) Average Recall@IoU:0.5-0.95 45.4 # 1
Object Detection TBBR FSAF (ResNeXt-101, ImageNet-1k pretrain) Average Recall@IoU:0.5-0.95 38.0 # 2
Object Detection TBBR FSAF (ResNeXt-101) Average Recall@IoU:0.5-0.95 24.8 # 6
Object Detection TBBR TridentNet (ResNet-50, ImageNet-1k pretrain) Average Recall@IoU:0.5-0.95 30.0 # 5
Object Detection TBBR TridentNet (ResNet-50) Average Recall@IoU:0.5-0.95 21.5 # 7
Object Detection TBBR Mask R-CNN (ResNet-50-FPN) Average Recall@IoU:0.5-0.95 30.8 # 4
Object Detection TBBR Mask R-CNN (ResNet-50-FPN, ImageNet-1k pretrain) Average Recall@IoU:0.5-0.95 37.0 # 3
Instance Segmentation TBBR Mask R-CNN (ResNet-50-FPN) Average Recall@IoU:0.5-0.95 20.1 # 4
Instance Segmentation TBBR Mask R-CNN (ResNet-50-FPN, ImageNet-1k pretrain) Average Recall@IoU:0.5-0.95 21.9 # 2
Instance Segmentation TBBR Swin-T Average Recall@IoU:0.5-0.95 20.6 # 3
Instance Segmentation TBBR Swin-T (ImageNet-1k pretrain) Average Recall@IoU:0.5-0.95 28.0 # 1

Methods