Fix upload anno for COCO (#788)

* COCO: load bbox as rectangle if segmentation field is empty
* added unit test for coco format (case: object segment field is empty)

cvat/apps/annotation/README.md

@@ -315,7 +315,8 @@ It may take some time.
 
 #### COCO loader description
 - uploaded file: single unpacked `*.json`.
-- supported shapes: Polygons (the `segmentation` must not be empty)
+- supported shapes: object is interpreted as Polygon if the `segmentation` field of annotation is not empty
+  else as Rectangle with coordinates from `bbox` field.
 - additional comments: the CVAT task should be created with the full label set that may be in the annotation files
 
 #### How to create a task from MS COCO dataset

cvat/apps/annotation/coco.py

@@ -344,11 +344,12 @@ def load(file_object, annotations):
         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):
@@ -375,3 +376,18 @@ def load(file_object, annotations):
                         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

@@ -280,9 +280,9 @@ class FloatArrayField(models.TextField):
     separator = ","
 
     def from_db_value(self, value, expression, connection):
-            if value is None:
-                return value
-            return [float(v) for v in value.split(self.separator)]
+        if not value:
+            return value
+        return [float(v) for v in value.split(self.separator)]
 
     def to_python(self, value):
         if isinstance(value, list):

cvat/apps/engine/serializers.py

@@ -366,7 +366,8 @@ class ShapeSerializer(serializers.Serializer):
     occluded = serializers.BooleanField()
     z_order = serializers.IntegerField(default=0)
     points = serializers.ListField(
-        child=serializers.FloatField(min_value=0)
+        child=serializers.FloatField(min_value=0),
+        allow_empty=False,
     )
 
 class LabeledShapeSerializer(ShapeSerializer, AnnotationSerializer):

cvat/apps/engine/tests/test_rest_api.py

@@ -2779,6 +2779,84 @@ def etree_to_dict(t):
         elif annotation_format_name == "MASK":
             self.assertTrue(zipfile.is_zipfile(content))
 
+
+    def _run_coco_annotation_upload_test(self, user):
+        def generate_coco_anno():
+            return b"""{
+            "categories": [
+                {
+                "id": 1,
+                "name": "car",
+                "supercategory": ""
+                },
+                {
+                "id": 2,
+                "name": "person",
+                "supercategory": ""
+                }
+            ],
+            "images": [
+                {
+                "coco_url": "",
+                "date_captured": "",
+                "flickr_url": "",
+                "license": 0,
+                "id": 0,
+                "file_name": "test_1.jpg",
+                "height": 720,
+                "width": 1280
+                }
+            ],
+            "annotations": [
+                {
+                "category_id": 1,
+                "id": 1,
+                "image_id": 0,
+                "iscrowd": 0,
+                "segmentation": [
+                    []
+                ],
+                "area": 17702.0,
+                "bbox": [
+                    574.0,
+                    407.0,
+                    167.0,
+                    106.0
+                ]
+                }
+            ]
+            }"""
+
+        response = self._get_annotation_formats(user)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        supported_formats = response.data
+        self.assertTrue(isinstance(supported_formats, list) and supported_formats)
+
+        coco_format = None
+        for f in response.data:
+            if f["name"] == "COCO":
+                coco_format = f
+                break
+        self.assertTrue(coco_format)
+        loader = coco_format["loaders"][0]
+
+        task, _ = self._create_task(user, user)
+
+        content = io.BytesIO(generate_coco_anno())
+        content.seek(0)
+
+        uploaded_data = {
+            "annotation_file": content,
+        }
+        response = self._upload_api_v1_tasks_id_annotations(task["id"], user, uploaded_data, "format={}".format(loader["display_name"]))
+        self.assertEqual(response.status_code, status.HTTP_202_ACCEPTED)
+
+        response = self._upload_api_v1_tasks_id_annotations(task["id"], user, {}, "format={}".format(loader["display_name"]))
+        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+
+        response = self._get_api_v1_tasks_id_annotations(task["id"], user)
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+
     def test_api_v1_tasks_id_annotations_admin(self):
         self._run_api_v1_tasks_id_annotations(self.admin, self.assignee,
             self.assignee)
@@ -2801,6 +2879,9 @@ def test_api_v1_tasks_id_annotations_dump_load_user(self):
     def test_api_v1_tasks_id_annotations_dump_load_no_auth(self):
         self._run_api_v1_tasks_id_annotations_dump_load(self.user, self.assignee, None)
 
+    def test_api_v1_tasks_id_annotations_upload_coco_user(self):
+        self._run_coco_annotation_upload_test(self.user)
+
 class ServerShareAPITestCase(APITestCase):
     def setUp(self):
         self.client = APIClient()