[Datumaro] Fix duplicating keypoints in COCO export (#1435)

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - Auto annotation, TF annotation and Auto segmentation apps (https://github.com/opencv/cvat/pull/1409)
 - Import works with truncated images now: "OSError:broken data stream" on corrupt images (https://github.com/opencv/cvat/pull/1430)
+- Duplicating keypoints in COCO export (https://github.com/opencv/cvat/pull/1435)
 
 ### Security
 -

datumaro/datumaro/plugins/coco_format/converter.py

@@ -352,8 +352,7 @@ class _KeypointsConverter(_InstancesConverter):
             instance = [points, [], None, points.get_bbox()]
             elem = super().convert_instance(instance, item)
             elem.update(self.convert_points_object(points))
-            if elem:
-                self.annotations.append(elem)
+            self.annotations.append(elem)
 
         # Create annotations for complete instance + keypoints annotations
         super().save_annotations(item)
@@ -390,7 +389,8 @@ class _KeypointsConverter(_InstancesConverter):
 
     def convert_instance(self, instance, item):
         points_ann = find(item.annotations, lambda x: \
-            x.type == AnnotationType.points and x.group == instance[0].group)
+            x.type == AnnotationType.points and \
+            instance[0].group and x.group == instance[0].group)
         if not points_ann:
             return None
 

datumaro/tests/test_coco_format.py

@@ -556,7 +556,7 @@ class CocoConverterTest(TestCase):
                             Points([1, 2, 3, 4, 2, 3], group=2, id=2),
                             Bbox(1, 2, 2, 2, group=2, id=2),
                         ]),
-                    DatasetItem(id=2, subset='train',
+                    DatasetItem(id=2, subset='train', image=np.zeros((5, 4, 3)),
                         annotations=[
                             # Solitary keypoints
                             Points([1, 2, 0, 2, 4, 1], label=5, id=3),