feat(simulator): add image saving utilities for verification

mini-nav/simulator/__init__.py

@@ -3,16 +3,19 @@ from .habitat import (
     close_habitat_simulator,
     create_habitat_simulator,
 )
+from .image_save import save_object_image, save_room_view
 from .topdown import TopDownRenderStyle, TopDownSceneElements, render_topdown_scene_map
 from .views import RoomViewsByRoom, collect_room_views_by_room
 
 __all__ = [
     "HabitatSimulatorConfig",
+    "RoomViewsByRoom",
     "TopDownRenderStyle",
     "TopDownSceneElements",
-    "RoomViewsByRoom",
     "close_habitat_simulator",
     "collect_room_views_by_room",
     "create_habitat_simulator",
     "render_topdown_scene_map",
+    "save_object_image",
+    "save_room_view",
 ]

mini-nav/simulator/image_save.py

@@ -0,0 +1,59 @@
+"""Image saving utilities for simulation verification output."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+from PIL import Image
+
+
+def save_room_view(
+    output_dir: Path,
+    room_id: str,
+    view_idx: int,
+    image: Image.Image,
+) -> Path:
+    """Save a single room view image to disk.
+
+    Args:
+        output_dir: Base output directory.
+        room_id: Room identifier string.
+        view_idx: Zero-based view index within the room.
+        image: PIL Image to save.
+
+    Returns:
+        Path where the image was saved.
+    """
+    room_dir = output_dir / room_id
+    room_dir.mkdir(parents=True, exist_ok=True)
+    path = room_dir / f"view_{view_idx:03d}.png"
+    image.convert("RGB").save(path, format="PNG")
+    return path
+
+
+def save_object_image(
+    output_dir: Path,
+    room_id: str,
+    obj_id: str,
+    view_idx: int,
+    mask_idx: int,
+    image: Image.Image,
+) -> Path:
+    """Save a masked object image to disk.
+
+    Args:
+        output_dir: Base output directory.
+        room_id: Room identifier string.
+        obj_id: Object identifier string.
+        view_idx: Zero-based view index.
+        mask_idx: Zero-based mask index within the view.
+        image: PIL Image to save.
+
+    Returns:
+        Path where the image was saved.
+    """
+    room_dir = output_dir / room_id
+    room_dir.mkdir(parents=True, exist_ok=True)
+    path = room_dir / f"{obj_id}_view{view_idx:03d}_mask{mask_idx:02d}.png"
+    image.convert("RGB").save(path, format="PNG")
+    return path

mini-nav/utils/__init__.py

@@ -4,6 +4,7 @@ from .feature_extractor import (
     extract_single_image_feature,
     infer_vector_dim,
 )
+from .image import numpy_to_pil
 
 __all__ = [
     "get_device",
@@ -11,4 +12,5 @@ __all__ = [
     "infer_vector_dim",
     "extract_single_image_feature",
     "extract_batch_features",
+    "numpy_to_pil",
 ]

mini-nav/utils/image.py

@@ -0,0 +1,21 @@
+"""Image conversion utilities."""
+
+from __future__ import annotations
+
+import numpy as np
+from PIL import Image
+
+
+def numpy_to_pil(rgb: np.ndarray) -> Image.Image:
+    """Convert an RGB numpy array to a PIL Image.
+
+    Handles arrays with 4 channels (RGBA) by dropping the alpha channel.
+
+    Args:
+        rgb: Numpy array of shape (H, W, C) with dtype uint8 or compatible.
+
+    Returns:
+        PIL Image in RGB mode.
+    """
+    rgb3 = rgb[..., :3] if rgb.shape[-1] > 3 else rgb
+    return Image.fromarray(rgb3.astype(np.uint8))