Incorrect import of Kitti 1.0 annotations that contain both polygons and bboxes

[archibald1418]

If an annotation archive contains both polygons (=segmentation) and bboxes (=detection), objects of only the first type that was found are imported, while objects of other type are not.

Steps to reproduce in app.cvat.ai

• open a clean job
• add a polygon
• add two shapes, save
• export
• clean annotations, save
• import the archive
• new annotations contain only one object (a polygon)
  It works vice-versa if the first annotation is a rectangle(=bbox)
  (there is also already a unit test for this)

Note that, bboxes alone and polygons alone are treated correctly. The issue is only when they are together in the same annotation.

Why does it happen?

Here, if KittiImporter detects both annotation types, it treats them as conflicting and gives priority to objects of first found type. This results in polygons missing from annotations when they are added together with bboxes, and bboxes if vice-versa

This is reportedly a design choice in order to avoid conflicts between classes

Possible solutions

• propose a fix to include both annotation types (detection & segmentation)
• if not possible, perhaps a notification message explaining that annotations with only one annotation type are supported?