updates to account for edge case polygons

Author: jtsodapop

labelbox/data/annotation_types/geometry/mask.py

@@ -98,7 +98,8 @@ def draw(self,
 
     def _extract_polygons_from_contours(self, contours: List) -> MultiPolygon:
         contours = map(np.squeeze, contours)
-        polygons = map(Polygon, contours)
+        filtered_contours = filter(lambda contour: len(contour) > 2, contours)
+        polygons = map(Polygon, filtered_contours)
         return MultiPolygon(polygons)
 
     def create_url(self, signer: Callable[[bytes], str]) -> str:

labelbox/data/serialization/coco/instance_dataset.py

@@ -21,6 +21,8 @@ def mask_to_coco_object_annotation(annotation: ObjectAnnotation, annot_idx: int,
     # This is going to fill any holes into the multipolygon
     # If you need to support holes use the panoptic data format
     shapely = annotation.value.shapely.simplify(1).buffer(0)
+    if shapely.is_empty:
+        shapely = annotation.value.shapely.simplify(1).buffer(0.01)
     xmin, ymin, xmax, ymax = shapely.bounds
     # Iterate over polygon once or multiple polygon for each item
     area = shapely.area