COCO: load bbox as rectangle if segmentation field is empty

cvat/apps/annotation/coco.py

@@ -364,11 +364,12 @@ def match_frame(frame_info, filename):
         for ann in anns:
             group = 0
             label_name = labels[ann['category_id']]
+            polygons = []
             if 'segmentation' in ann:
-                polygons = []
                 # polygon
                 if ann['iscrowd'] == 0:
-                    polygons = ann['segmentation']
+                    # filter non-empty polygons
+                    polygons = [polygon for polygon in ann['segmentation'] if polygon]
                 # mask
                 else:
                     if isinstance(ann['segmentation']['counts'], list):
@@ -395,3 +396,18 @@ def match_frame(frame_info, filename):
                         attributes=[],
                         group=group,
                     ))
+
+            if not polygons and 'bbox' in ann and isinstance(ann['bbox'], list):
+                xtl = ann['bbox'][0]
+                ytl = ann['bbox'][1]
+                xbr = xtl + ann['bbox'][2]
+                ybr = ytl + ann['bbox'][3]
+                annotations.add_shape(annotations.LabeledShape(
+                    type='rectangle',
+                    frame=frame_number,
+                    label=label_name,
+                    points=[xtl, ytl, xbr, ybr],
+                    occluded=False,
+                    attributes=[],
+                    group=group,
+                ))

cvat/apps/engine/models.py

@@ -280,7 +280,7 @@ class FloatArrayField(models.TextField):
     separator = ","
 
     def from_db_value(self, value, expression, connection):
-        if value is None:
+        if value is None or not value:
             return value
         return [float(v) for v in value.split(self.separator)]