Support for semantic segmentation

[montmejat]

I saw that torchmetrics.detection.mean_ap.MeanAveragePrecision supports segmentation masks in iou_type . It's nice but I'm trying to compute metrics for semantic segmentation (it doesn't cover pixel accuracy or mean iou for example, only precision and recall).

Also, when trying to use MeanAveragePrecision for iou_type='segm' it stills forces me to include scores and labels which is an information already in my masks (the mask index is the label, and the scores are included in the masks). It doesn't seem very intuitive to me!

Unless I've missed something, it would be nice to have to have support for semantic segmentation :smile:

[github-actions[bot]]

Hi! thanks for your contribution!, great first issue!

[ogencoglu]

+1 for semantic segmentation metrics