support on-disk instance segmentations in SDK

docs/source/user_guide/using_datasets.rst

@@ -2542,7 +2542,7 @@ Object detections stored in |Detections| may also have instance segmentation
 masks.
 
 These masks can be stored in one of two ways: either directly in the database
-via the :attr:`mask<fiftyone.core.labels.Detection.mask>` attribute, or on
+via the :attr:`mask <fiftyone.core.labels.Detection.mask>` attribute, or on
 disk referenced by the
 :attr:`mask_path <fiftyone.core.labels.Detection.mask_path>` attribute.
 
@@ -2605,8 +2605,10 @@ object's bounding box when visualizing in the App.
                 <Detection: {
                     'id': '5f8709282018186b6ef6682b',
                     'attributes': {},
+                    'tags': [],
                     'label': 'cat',
                     'bounding_box': [0.48, 0.513, 0.397, 0.288],
+                    'mask': None,
                     'mask_path': '/path/to/mask.png',
                     'confidence': 0.96,
                     'index': None,
@@ -2615,8 +2617,8 @@ object's bounding box when visualizing in the App.
         }>,
     }>
 
-Like all |Label| types, you can also add custom attributes to your detections
-by dynamically adding new fields to each |Detection| instance:
+Like all |Label| types, you can also add custom attributes to your instance
+segmentations by dynamically adding new fields to each |Detection| instance:
 
 .. code-block:: python
     :linenos:

fiftyone/core/collections.py

@@ -10681,6 +10681,9 @@ def _get_media_fields(
                 app_media_fields.discard("filepath")
 
         for field_name, field in schema.items():
+            while isinstance(field, fof.ListField):
+                field = field.field
+
             if field_name in app_media_fields:
                 media_fields[field_name] = None
             elif isinstance(field, fof.EmbeddedDocumentField) and issubclass(

fiftyone/core/labels.py

@@ -409,7 +409,8 @@ class Detection(_HasAttributesDict, _HasID, _HasMedia, Label):
             its bounding box, which should be a 2D binary or 0/1 integer numpy
             array
         mask_path (None):  the absolute path to the instance segmentation image
-            on disk
+            on disk, which should be a single-channel PNG image where any
+            non-zero values represent the instance's extent
         confidence (None): a confidence in ``[0, 1]`` for the detection
         index (None): an index for the object
         attributes ({}): a dict mapping attribute names to :class:`Attribute`
@@ -532,8 +533,8 @@ def to_segmentation(self, mask=None, frame_size=None, target=255):
         """
         if not self.has_mask:
             raise ValueError(
-                "Only detections with their `mask` attributes populated can "
-                "be converted to segmentations"
+                "Only detections with their `mask` or `mask_path` attribute "
+                "populated can be converted to segmentations"
             )
 
         mask, target = _parse_segmentation_target(mask, frame_size, target)

fiftyone/utils/data/exporters.py

@@ -12,11 +12,13 @@
 import warnings
 from collections import defaultdict
 
+from bson import json_util
+import pydash
+
 import eta.core.datasets as etad
 import eta.core.frameutils as etaf
 import eta.core.serial as etas
 import eta.core.utils as etau
-from bson import json_util
 
 import fiftyone as fo
 import fiftyone.core.collections as foc
@@ -2029,34 +2031,38 @@ def _export_frame_labels(self, sample, uuid):
 
     def _export_media_fields(self, sd):
         for field_name, key in self._media_fields.items():
-            value = sd.get(field_name, None)
-            if value is None:
-                continue
-
-            if key is not None:
-                self._export_media_field(value, field_name, key=key)
-            else:
-                self._export_media_field(sd, field_name)
+            self._export_media_field(sd, field_name, key=key)
 
     def _export_media_field(self, d, field_name, key=None):
-        if key is not None:
-            value = d.get(key, None)
-        else:
-            key = field_name
-            value = d.get(field_name, None)
-
+        value = pydash.get(d, field_name, None)
         if value is None:
             return
 
         media_exporter = self._get_media_field_exporter(field_name)
-        outpath, _ = media_exporter.export(value)
 
-        if self.abs_paths:
-            d[key] = outpath
-        else:
-            d[key] = fou.safe_relpath(
-                outpath, self.export_dir, default=outpath
-            )
+        if not isinstance(value, (list, tuple)):
+            value = [value]
+
+        for _d in value:
+            if key is not None:
+                _value = _d.get(key, None)
+            else:
+                _value = _d
+
+            if _value is None:
+                continue
+
+            outpath, _ = media_exporter.export(_value)
+
+            if not self.abs_paths:
+                outpath = fou.safe_relpath(
+                    outpath, self.export_dir, default=outpath
+                )
+
+            if key is not None:
+                _d[key] = outpath
+            else:
+                pydash.set_(d, field_name, outpath)
 
     def _get_media_field_exporter(self, field_name):
         media_exporter = self._media_field_exporters.get(field_name, None)
@@ -2333,33 +2339,43 @@ def _prep_sample(sd):
 
     def _export_media_fields(self, sd):
         for field_name, key in self._media_fields.items():
-            value = sd.get(field_name, None)
-            if value is None:
-                continue
+            self._export_media_field(sd, field_name, key=key)
+
+    def _export_media_field(self, d, field_name, key=None):
+        value = pydash.get(d, field_name, None)
+        if value is None:
+            return
 
+        media_exporter = self._get_media_field_exporter(field_name)
+
+        if not isinstance(value, (list, tuple)):
+            value = [value]
+
+        for _d in value:
             if key is not None:
-                self._export_media_field(value, field_name, key=key)
+                _value = _d.get(key, None)
             else:
-                self._export_media_field(sd, field_name)
+                _value = _d
 
-    def _export_media_field(self, d, field_name, key=None):
-        if key is not None:
-            value = d.get(key, None)
-        else:
-            key = field_name
-            value = d.get(field_name, None)
+            if _value is None:
+                continue
 
-        if value is None:
-            return
+            if self.export_media is not False:
+                # Store relative path
+                _, uuid = media_exporter.export(_value)
+                outpath = os.path.join("fields", field_name, uuid)
+            elif self.rel_dir is not None:
+                # Remove `rel_dir` prefix from path
+                outpath = fou.safe_relpath(
+                    _value, self.rel_dir, default=_value
+                )
+            else:
+                continue
 
-        if self.export_media is not False:
-            # Store relative path
-            media_exporter = self._get_media_field_exporter(field_name)
-            _, uuid = media_exporter.export(value)
-            d[key] = os.path.join("fields", field_name, uuid)
-        elif self.rel_dir is not None:
-            # Remove `rel_dir` prefix from path
-            d[key] = fou.safe_relpath(value, self.rel_dir, default=value)
+            if key is not None:
+                _d[key] = outpath
+            else:
+                pydash.set_(d, field_name, outpath)
 
     def _get_media_field_exporter(self, field_name):
         media_exporter = self._media_field_exporters.get(field_name, None)

fiftyone/utils/data/importers.py

@@ -14,6 +14,7 @@
 
 from bson import json_util
 from mongoengine.base import get_document
+import pydash
 
 import eta.core.datasets as etad
 import eta.core.image as etai
@@ -2151,32 +2152,43 @@ def _import_runs(dataset, runs, results_dir, run_cls):
 
 def _parse_media_fields(sd, media_fields, rel_dir):
     for field_name, key in media_fields.items():
-        value = sd.get(field_name, None)
+        value = pydash.get(sd, field_name, None)
         if value is None:
             continue
 
         if isinstance(value, dict):
-            if key is False:
-                try:
-                    _cls = value.get("_cls", None)
-                    key = get_document(_cls)._MEDIA_FIELD
-                except Exception as e:
-                    logger.warning(
-                        "Failed to infer media field for '%s'. Reason: %s",
-                        field_name,
-                        e,
-                    )
-                    key = None
-
-                media_fields[field_name] = key
-
-            if key is not None:
-                path = value.get(key, None)
-                if path is not None and not os.path.isabs(path):
-                    value[key] = os.path.join(rel_dir, path)
+            _parse_nested_media_field(
+                value, media_fields, rel_dir, field_name, key
+            )
+        elif isinstance(value, list):
+            for d in value:
+                _parse_nested_media_field(
+                    d, media_fields, rel_dir, field_name, key
+                )
         elif etau.is_str(value):
             if not os.path.isabs(value):
-                sd[field_name] = os.path.join(rel_dir, value)
+                pydash.set_(sd, field_name, os.path.join(rel_dir, value))
+
+
+def _parse_nested_media_field(d, media_fields, rel_dir, field_name, key):
+    if key is False:
+        try:
+            _cls = d.get("_cls", None)
+            key = get_document(_cls)._MEDIA_FIELD
+        except Exception as e:
+            logger.warning(
+                "Failed to infer media field for '%s'. Reason: %s",
+                field_name,
+                e,
+            )
+            key = None
+
+        media_fields[field_name] = key
+
+    if key is not None:
+        path = d.get(key, None)
+        if path is not None and not os.path.isabs(path):
+            d[key] = os.path.join(rel_dir, path)
 
 
 class ImageDirectoryImporter(UnlabeledImageDatasetImporter):