what does ReLabel mean?

[dongzhuoyao]

ReLabel(255, args.n_class - 1),  # Last Class is "Void" or "Background" class

actually, the args.n_class - 1 means 'bicyle' in cityscapes.

so you will map all unsure pixels to bicycle?

[LittleWat]

I am sorry that our codes are confusing.

When the setting is "GTA to Cityscapes", we have 20 classes (= args.n_class) including background class. (19 classes are used for evaluation.)
So the (args.n_class - 1) = 19 means 'Background' in both GTA and Cityscapes.
Class ID "0" means 'road' and Class ID "18" means 'bicycle'.