RVC 2020 Branch

[johnwlambert]

This branch provides support for our submissions to the the 2020 Robust Vision Challenge (RVC).

It includes:

• mappings from our universal taxonomy backwards to ADE20K, Cityscapes, KITTI, Mapillary Vistas, ScanNet, VIPER, WildDashV2. Please keep in mind that some of these backwards mappings are lossy, for example if a merge previously occurred.
• paired test set datalists to use the mseg/label_preparation/remap_dataset.py script to prepare submissions on disk.
• A script to analyze the per-class frequencies of any dataset, using tests/class_density_analysis.py
• A script to visualize individual masks of all classes from any dataset, using tests/visualize_specific_class_examples.py