How to generate the annotation json file and PNG file using predicted panoptic segmentation result?

[zly9120]

Now I use ddetectron2 get the result of panoptic FPN model.
And I wanna to use this to evaluate to caculate the PQ metric data, but it need the annoatation json file and segmentation PNG file. So I have to do this work , can you help me ? or do you have another method for this? pls teach me, thank you !