Substation segmentation

The aim of this project is to build a computer vision model for segmenting substations in Sentinel 2 satellite imagery. This directory contains code to train and evaluate multiple kinds of segmentation models. We experiment with different kinds of architectures, losses and training strategies. The associated paper is here

The directory structure:

• dataset
  • substation
    • image_stack
    • mask
    • negatives
      • image_stack
      • mask
    • four_or_more_timepoints.pkl
  • PhilEO-downstream/processed_dataset
    • train
      • images
      • building_mask
      • road_mask
      • lc_mask
    • test
    • val
• dataloader.py - creates dataloader for the training
• models.py - creates and instantiates different kinds of models
• utils.py - stores the helped functions
• train.py - training script
• inference.ipynb - script to run inference from trained models on images

Dataset Details:

Substation Dataset

• dataset/image_stack and dataset/mask folders contain all the images and masks respectively.
• There are a a total of 26522 images-mask pairs stored as numpy files.
• Each image is multi-temporal and contains multiple shots taken at the same place during different revisits. Majority of the files contains images from 5 revisits.
• Each image is multi-spectral and contains 13 channels
• Spatial Resolution of each image is 228*228.
• You can download the dataset from here - images and masks
• The negatives comprising of global random images can be found here - images and masks
• Sample image and mask pair are given below -

PhilEO Dataset

• You can find more information about this dataset on huggingface
• Sample image and building mask pair are given below -

Running Training Scripts

For Training UNet-

python3 Sentinel.py --model_dir --batch_size --workers --learning_rate 1e-3 --upsampled_mask_size --upsampled_image_size --in_channels <set to 13 for using all channels or 3 for using RGB input> --seed --model_type --normalizing_type constant --normalizing_factor 4000 --exp_name --exp_number --loss BCE --pretrained [add this to use pretrained encoder] --use_timepoints [add this to enable multi-temporal input]

For Training SWIN model-

python3 SwinTransformerPipeline.py --model_dir --batch_size --workers --learning_rate 5e-4 --upsampled_mask_size --upsampled_image_size --in_channels <set to 13 for using all channels or 3 for using RGB input> --seed --model_type swin --normalizing_type constant --normalizing_factor 4000 --exp_name --exp_number --loss BCE --pretrained [add this to use pretrained encoder] --use_timepoints [add this to enable multi-temporal input] --learned_upsampling [to append learnable Up-Conv layers at the end of FPN network to upsample Output Mask to Input Image size]

Training Curves and Sample Outputs

We train all models by minimizing Per-Pixel Binary Cross Entropy Loss and compute Intersection over Union(IoU) to test models. We achieve an impressive IoU score of 58% on test data using the SWIN Model. The loss and IoU curves are given below -

Sample outputs from our best models areprovided below -

References

• Copernicus Sentinel data [2023]. https://scihub.copernicus.eu/
• Open Street Map. https://www.openstreetmap.org/copyright
• Transition Zero. https://www.transitionzero.org/
• Ze Liu et al. Swin Transformer: Hierarchical Vision Transformer using Shifted Windows. 2021. arXiv: 2103.14030 [cs.CV].
• Muhammed Razzak et al. Multi-Spectral Multi-Image Super-Resolution of Sentinel-2 with Radiometric Consistency Losses and Its Effect on Building Delineation. 2021. arXiv: 2111.03231 [eess.IV].
• Olaf Ronneberger, Philipp Fischer, and Thomas Brox. U-Net: Convolutional Networks for Biomedical Image Segmentation. 2015. arXiv: 1505. 04597 [cs.CV].
• Adam J. Stewart et al. “TorchGeo: Deep Learning With Geospatial Data”. In: Proceedings of the 30th International Conference on Advances in Geographic Information Systems. SIGSPATIAL ’22. Seattle, Washington: Association for Computing Machinery, Nov. 2022, pp. 1–12. doi: 10.1145/3557915.3560953. url: https://dl.acm.org/doi/10.1145/3557915.3560953.
• Piper Wolters, Favyen Bastani, and Aniruddha Kembhavi. Zooming Out on Zooming In: Advancing Super-Resolution for Remote Sensing. 2023. arXiv:2311.18082 [cs.CV].

Contact

For questions and queries please reach out to Kartik Jindgar and Grace Lindsay