(depth image processing): excluding depth frames from the RGB to BGR image processing (#4135)

* (depth image processing): excluding depth frames from the RGB to BGR image processing

* test(update): updating tests to include RGB/BGR conversion checks

src/lerobot/cameras/reachy2_camera/reachy2_camera.py

@@ -173,7 +173,8 @@ class Reachy2Camera(Camera):
             raise ValueError(
                 f"Invalid color mode '{self.color_mode}'. Expected {ColorMode.RGB} or {ColorMode.BGR}."
             )
-        if self.color_mode == ColorMode.RGB:
+        is_depth_frame = self.config.name == "depth" and self.config.image_type == "depth"
+        if not is_depth_frame and self.color_mode == ColorMode.RGB:
             frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
 
         self.latest_frame = frame

src/lerobot/cameras/realsense/camera_realsense.py

@@ -453,7 +453,7 @@ class RealSenseCamera(Camera):
             )
 
         processed_image = image
-        if self.color_mode == ColorMode.BGR:
+        if not depth_frame and self.color_mode == ColorMode.BGR:
             processed_image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)
 
         if self.rotation in [cv2.ROTATE_90_CLOCKWISE, cv2.ROTATE_90_COUNTERCLOCKWISE, cv2.ROTATE_180]:

tests/cameras/test_opencv.py

@@ -26,7 +26,7 @@ import cv2
 import numpy as np
 import pytest
 
-from lerobot.cameras.configs import Cv2Rotation
+from lerobot.cameras.configs import ColorMode, Cv2Rotation
 from lerobot.cameras.opencv import OpenCVCamera, OpenCVCameraConfig
 from lerobot.utils.errors import DeviceAlreadyConnectedError, DeviceNotConnectedError
 
@@ -132,6 +132,28 @@ def test_read(index_or_path):
         assert isinstance(img, np.ndarray)
 
 
+@pytest.mark.parametrize("index_or_path", TEST_IMAGE_PATHS, ids=TEST_IMAGE_SIZES)
+def test_color_mode_conversion(index_or_path):
+    """RGB and BGR reads of the same frame must differ only by a channel-axis reversal."""
+    rgb_config = OpenCVCameraConfig(index_or_path=index_or_path, color_mode=ColorMode.RGB, warmup_s=0)
+    bgr_config = OpenCVCameraConfig(index_or_path=index_or_path, color_mode=ColorMode.BGR, warmup_s=0)
+    with OpenCVCamera(rgb_config) as rgb_cam:
+        rgb = rgb_cam.read()
+    with OpenCVCamera(bgr_config) as bgr_cam:
+        bgr = bgr_cam.read()
+
+    assert rgb.shape == bgr.shape
+    np.testing.assert_array_equal(rgb, bgr[..., ::-1])
+
+
+def test_postprocess_invalid_color_mode():
+    config = OpenCVCameraConfig(index_or_path=DEFAULT_PNG_FILE_PATH)
+    camera = OpenCVCamera(config)
+    camera.color_mode = "invalid"
+    with pytest.raises(ValueError):
+        camera._postprocess_image(np.zeros((120, 160, 3), dtype=np.uint8))
+
+
 def test_read_before_connect():
     config = OpenCVCameraConfig(index_or_path=DEFAULT_PNG_FILE_PATH)
 

tests/cameras/test_reachy2_camera.py

@@ -22,6 +22,7 @@ import pytest
 
 pytest.importorskip("reachy2_sdk")
 
+from lerobot.cameras.configs import ColorMode
 from lerobot.cameras.reachy2_camera import Reachy2Camera, Reachy2CameraConfig
 from lerobot.utils.errors import DeviceNotConnectedError
 
@@ -33,28 +34,19 @@ PARAMS = [
 ]
 
 
-def _make_cam_manager_mock():
+def _make_cam_manager_mock(color_frame, depth_frame=None):
     c = MagicMock(name="CameraManagerMock")
 
     teleop = MagicMock(name="TeleopCam")
     teleop.width = 640
     teleop.height = 480
-    teleop.get_frame = MagicMock(
+    teleop.get_frame = MagicMock(side_effect=lambda *_, **__: (color_frame, time.time()))
-        side_effect=lambda *_, **__: (
-            np.zeros((480, 640, 3), dtype=np.uint8),
-            time.time(),
-        )
-    )
 
     depth = MagicMock(name="DepthCam")
     depth.width = 640
     depth.height = 480
-    depth.get_frame = MagicMock(
+    depth.get_frame = MagicMock(side_effect=lambda *_, **__: (color_frame, time.time()))
-        side_effect=lambda *_, **__: (
+    depth.get_depth_frame = MagicMock(side_effect=lambda *_, **__: (depth_frame, time.time()))
-            np.zeros((480, 640, 3), dtype=np.uint8),
-            time.time(),
-        )
-    )
 
     c.is_connected.return_value = True
     c.teleop = teleop
@@ -84,12 +76,14 @@ def _make_cam_manager_mock():
     # ids=["teleop-left", "teleop-right", "torso-rgb", "torso-depth"],
     ids=["teleop-left", "teleop-right", "torso-rgb"],
 )
-def camera(request):
+def camera(request, img_array_factory):
     name, image_type = request.param
+    color_frame = img_array_factory(height=480, width=640)
+    depth_frame = img_array_factory(height=480, width=640, channels=1, dtype=np.uint16)[..., 0]
     with (
         patch(
             "lerobot.cameras.reachy2_camera.reachy2_camera.CameraManager",
-            side_effect=lambda *a, **k: _make_cam_manager_mock(),
+            side_effect=lambda *a, **k: _make_cam_manager_mock(color_frame, depth_frame),
         ),
     ):
         config = Reachy2CameraConfig(name=name, image_type=image_type)
@@ -188,6 +182,41 @@ def test_read_latest_too_old(camera):
         _ = camera.read_latest(max_age_ms=0)  # immediately too old
 
 
+def test_color_mode_conversion(img_array_factory):
+    """teleop frames are native BGR: RGB reverses the channel axis, BGR is passed through."""
+    frame = img_array_factory(height=8, width=8)
+
+    outputs = {}
+    for color_mode in (ColorMode.RGB, ColorMode.BGR):
+        with patch(
+            "lerobot.cameras.reachy2_camera.reachy2_camera.CameraManager",
+            side_effect=lambda *a, **k: _make_cam_manager_mock(frame),
+        ):
+            cam = Reachy2Camera(Reachy2CameraConfig(name="teleop", image_type="left", color_mode=color_mode))
+            cam.connect()
+            outputs[color_mode] = cam.read()
+            cam.disconnect()
+
+    np.testing.assert_array_equal(outputs[ColorMode.BGR], frame)
+    np.testing.assert_array_equal(outputs[ColorMode.RGB], frame[..., ::-1])
+
+
+def test_depth_frame_not_color_converted(img_array_factory):
+    """A depth/depth frame must be returned as-is, without BGR<->RGB conversion."""
+    color_frame = img_array_factory(height=8, width=8)
+    depth = img_array_factory(height=8, width=8, channels=1, dtype=np.uint16)[..., 0]
+    with patch(
+        "lerobot.cameras.reachy2_camera.reachy2_camera.CameraManager",
+        side_effect=lambda *a, **k: _make_cam_manager_mock(color_frame, depth_frame=depth),
+    ):
+        cam = Reachy2Camera(Reachy2CameraConfig(name="depth", image_type="depth"))
+        cam.connect()
+        out = cam.read()
+        cam.disconnect()
+
+    np.testing.assert_array_equal(out, depth)
+
+
 def test_wrong_camera_name():
     with pytest.raises(ValueError):
         _ = Reachy2CameraConfig(name="wrong-name", image_type="left")

tests/cameras/test_realsense.py

@@ -25,7 +25,7 @@ from unittest.mock import patch
 import numpy as np
 import pytest
 
-from lerobot.cameras.configs import Cv2Rotation
+from lerobot.cameras.configs import ColorMode, Cv2Rotation
 from lerobot.utils.errors import DeviceAlreadyConnectedError, DeviceNotConnectedError
 
 pytest.importorskip("pyrealsense2")
@@ -109,6 +109,32 @@ def test_read_depth():
     assert isinstance(img, np.ndarray)
 
 
+# These exercise _postprocess_image directly rather than read(): the bag playback returns
+# non-deterministic frames we can't compare against, and the depth read() path is skipped
+# (see test_read_depth) with the current pyrealsense2 version.
+def test_color_mode_conversion(img_array_factory):
+    """RGB (native for RealSense) is passed through; BGR reverses the channel axis."""
+    color = img_array_factory(height=3, width=4)
+
+    outputs = {}
+    for color_mode in (ColorMode.RGB, ColorMode.BGR):
+        camera = RealSenseCamera(RealSenseCameraConfig(serial_number_or_name="042", color_mode=color_mode))
+        camera.capture_height, camera.capture_width = color.shape[:2]
+        outputs[color_mode] = camera._postprocess_image(color)
+
+    np.testing.assert_array_equal(outputs[ColorMode.RGB], color)
+    np.testing.assert_array_equal(outputs[ColorMode.BGR], color[..., ::-1])
+
+
+def test_depth_frame_not_color_converted(img_array_factory):
+    """Depth frames must bypass color conversion, even when a BGR color_mode is set."""
+    camera = RealSenseCamera(RealSenseCameraConfig(serial_number_or_name="042", color_mode=ColorMode.BGR))
+    depth = img_array_factory(height=3, width=4, channels=1, dtype=np.uint16)[..., 0]
+    camera.capture_height, camera.capture_width = depth.shape
+
+    np.testing.assert_array_equal(camera._postprocess_image(depth, depth_frame=True), depth)
+
+
 def test_read_before_connect():
     config = RealSenseCameraConfig(serial_number_or_name="042")
     camera = RealSenseCamera(config)