first draft

lerobot/common/policies/diffusion/configuration_diffusion.py

@@ -130,14 +130,21 @@ class DiffusionConfig:
             raise ValueError(
                 f"`vision_backbone` must be one of the ResNet variants. Got {self.vision_backbone}."
             )
+        # There should only be one image key.
+        image_keys = {k for k in self.input_shapes if k.startswith("observation.image")}
+        if len(image_keys) != 1:
+            raise ValueError(
+                f"{self.__class__.__name__} only handles one image for now. Got image keys {image_keys}."
+            )
+        image_key = next(iter(image_keys))
         if (
-            self.crop_shape[0] > self.input_shapes["observation.image"][1]
-            or self.crop_shape[1] > self.input_shapes["observation.image"][2]
+            self.crop_shape[0] > self.input_shapes[image_key][1]
+            or self.crop_shape[1] > self.input_shapes[image_key][2]
         ):
             raise ValueError(
-                f'`crop_shape` should fit within `input_shapes["observation.image"]`. Got {self.crop_shape} '
-                f'for `crop_shape` and {self.input_shapes["observation.image"]} for '
-                '`input_shapes["observation.image"]`.'
+                f"`crop_shape` should fit within `input_shapes[{image_key}]`. Got {self.crop_shape} "
+                f"for `crop_shape` and {self.input_shapes[image_key]} for "
+                "`input_shapes[{image_key}]`."
             )
         supported_prediction_types = ["epsilon", "sample"]
         if self.prediction_type not in supported_prediction_types:

lerobot/common/policies/diffusion/modeling_diffusion.py

@@ -67,15 +67,31 @@ class DiffusionPolicy(nn.Module, PyTorchModelHubMixin):
         self.diffusion = DiffusionModel(config)
 
     def reset(self):
-        """
-        Clear observation and action queues. Should be called on `env.reset()`
-        """
+        """Clear observation and action queues. Should be called on `env.reset()`"""
         self._queues = {
             "observation.image": deque(maxlen=self.config.n_obs_steps),
             "observation.state": deque(maxlen=self.config.n_obs_steps),
             "action": deque(maxlen=self.config.n_action_steps),
         }
 
+    def _preprocess_batch_keys(self, batch: dict[str, Tensor], train_mode: bool = False):
+        """Check that the keys can be handled by this policy and standardize the image key.
+
+        This should be run after input normalization.
+        """
+        assert "observation.state" in batch
+        # There should only be one image key.
+        image_keys = {k for k in batch if k.startswith("observation.image") and not k.endswith("_is_pad")}
+        assert (
+            len(image_keys) == 1
+        ), f"{self.__class__.__name__} only handles one image for now. Got image keys {image_keys}."
+        if train_mode:
+            assert "action" in batch
+            assert "action_is_pad" in batch
+        image_key = next(iter(image_keys))
+        batch["observation.image"] = batch[image_key]
+        del batch[image_key]
+
     @torch.no_grad
     def select_action(self, batch: dict[str, Tensor]) -> Tensor:
         """Select a single action given environment observations.
@@ -98,10 +114,8 @@ class DiffusionPolicy(nn.Module, PyTorchModelHubMixin):
         "horizon" may not the best name to describe what the variable actually means, because this period is
         actually measured from the first observation which (if `n_obs_steps` > 1) happened in the past.
         """
-        assert "observation.image" in batch
-        assert "observation.state" in batch
-
         batch = self.normalize_inputs(batch)
+        self._preprocess_batch_keys(batch)
 
         self._queues = populate_queues(self._queues, batch)
 
@@ -121,6 +135,7 @@ class DiffusionPolicy(nn.Module, PyTorchModelHubMixin):
     def forward(self, batch: dict[str, Tensor]) -> dict[str, Tensor]:
         """Run the batch through the model and compute the loss for training or validation."""
         batch = self.normalize_inputs(batch)
+        self._preprocess_batch_keys(batch)
         batch = self.normalize_targets(batch)
         loss = self.diffusion.compute_loss(batch)
         return {"loss": loss}
@@ -185,13 +200,12 @@ class DiffusionModel(nn.Module):
 
     def generate_actions(self, batch: dict[str, Tensor]) -> Tensor:
         """
-        This function expects `batch` to have (at least):
+        This function expects `batch` to have:
         {
             "observation.state": (B, n_obs_steps, state_dim)
             "observation.image": (B, n_obs_steps, C, H, W)
         }
         """
-        assert set(batch).issuperset({"observation.state", "observation.image"})
         batch_size, n_obs_steps = batch["observation.state"].shape[:2]
         assert n_obs_steps == self.config.n_obs_steps
 
@@ -315,9 +329,13 @@ class DiffusionRgbEncoder(nn.Module):
 
         # Set up pooling and final layers.
         # Use a dry run to get the feature map shape.
+        image_keys = {k for k in config.input_shapes if k.startswith("observation.image")}
+        assert len(image_keys) == 1
         with torch.inference_mode():
             feat_map_shape = tuple(
-                self.backbone(torch.zeros(size=(1, *config.input_shapes["observation.image"]))).shape[1:]
+                self.backbone(
+                    torch.zeros(size=(1, config.input_shapes[next(iter(image_keys))][0], *config.crop_shape))
+                ).shape[1:]
             )
         self.pool = SpatialSoftmax(feat_map_shape, num_kp=config.spatial_softmax_num_keypoints)
         self.feature_dim = config.spatial_softmax_num_keypoints * 2

lerobot/scripts/train.py

@@ -8,6 +8,7 @@ import hydra
 import torch
 from datasets import concatenate_datasets
 from datasets.utils import disable_progress_bars, enable_progress_bars
+from omegaconf import DictConfig
 
 from lerobot.common.datasets.factory import make_dataset
 from lerobot.common.datasets.utils import cycle
@@ -290,7 +291,7 @@ def add_episodes_inplace(
     sampler.num_samples = len(concat_dataset)
 
 
-def train(cfg: dict, out_dir=None, job_name=None):
+def train(cfg: DictConfig, out_dir: str | None = None, job_name: str | None = None):
     if out_dir is None:
         raise NotImplementedError()
     if job_name is None: