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arthurdouillard / CVPR2021_PLOP

Official code of CVPR 2021's PLOP: Learning without Forgetting for Continual Semantic Segmentation
https://arxiv.org/abs/2011.11390
MIT License
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what is label "255" in target ? #32

Closed zhaoedf closed 2 years ago

zhaoedf commented 2 years ago

image

label "255" seem like some kind of edge to me? what is it for?

arthurdouillard commented 2 years ago

It's the "unknown" label commonly used in segmentation. This value is discarded both a train- and test-time.

Look at the ignore_index in the cross-entropy: https://github.com/arthurdouillard/CVPR2021_PLOP/blob/main/train.py#L76

zhaoedf commented 2 years ago

It's the "unknown" label commonly used in segmentation. This value is discarded both a train- and test-time.

Look at the ignore_index in the cross-entropy: https://github.com/arthurdouillard/CVPR2021_PLOP/blob/main/train.py#L76

dose this '255' exists in the original voc dataset? why not assign a specific label to these pixels or set it as bg?

you said this is commonly used in segmentation, where can i find more info? thx.

arthurdouillard commented 2 years ago

It exists in the original VOC dataset. You could consider it as bg, but usually that's not-well defined pixels on the boundaries, so everyone discard it.

Hum, I'm not sure about ref for that, just look at any dataset, they all have that

zhaoedf commented 2 years ago

It exists in the original VOC dataset. You could consider it as bg, but usually that's not-well defined pixels on the boundaries, so everyone discard it.

Hum, I'm not sure about ref for that, just look at any dataset, they all have that

i understood, thanks!