object colors in instance segmentation result are not unique

[YuechengLiu]

Hello, thank you for your greak work!

We meet some problem while using virtualhome.

1. We tried to get visible objects from first-person-view by calling comm.get_visible_objects(camera_id), but we found that some objects (which appeared in rgb image) are missing in the returned objects list.
2. We also tried to get the object list from first-person-view using the instance segmentation result (seg_inst), however, we found that the colors for instances are not unique (different object instances may have exactly the same color), so we can't get the instance id from the color map.

Looking forward to your response!