Allow hw synchronization of several realsense using a synchonization cable

realsense2_camera/launch/rs_launch.py

@@ -56,6 +56,7 @@
                            {'name': 'depth_module.exposure.2',      'default': '1', 'description': 'Depth module second exposure value. Used for hdr_merge filter'},
                            {'name': 'depth_module.gain.2',          'default': '16', 'description': 'Depth module second gain value. Used for hdr_merge filter'},
                            {'name': 'enable_sync',                  'default': 'false', 'description': "'enable sync mode'"},
+                           {'name': 'depth_module.inter_cam_sync_mode',               'default': "0", 'description': '[0-Default, 1-Master, 2-Slave]'},
                            {'name': 'enable_rgbd',                  'default': 'false', 'description': "'enable rgbd topic'"},
                            {'name': 'enable_gyro',                  'default': 'false', 'description': "'enable gyro stream'"},
                            {'name': 'enable_accel',                 'default': 'false', 'description': "'enable accel stream'"},

realsense2_camera/launch/rs_multi_camera_launch_sync.py

@@ -0,0 +1,83 @@
+# Copyright 2023 Intel Corporation. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# DESCRIPTION #
+# ----------- #
+# Use this launch file to launch 2 devices and enable the hardware synchronization. 
+# As describe in https://dev.intelrealsense.com/docs/multiple-depth-cameras-configuration both devices
+# have to be connected using a sync cable. The devices will by default stream asynchronously. 
+# Using this launch file one device will operate as master and the other as slave. As a result they will
+# capture at exactly the same time and rate. 
+# command line example: (to be adapted with the serial numbers or the used devices)
+# ros2 launch realsense2_camera rs_multi_camera_launch_sync.py camera_name1:=cam_1 camera_name2:=cam_2 camera_namespace1:=camera camera_namespace2:=camera serial_no1:="'_031422250097'" serial_no2:="'_336222301921'"
+# The value of the param can be checked using ros2 param get /camera/cam_1 depth_module.inter_cam_sync_mode and ros2 param get /camera/cam_2 depth_module.inter_cam_sync_mode
+
+"""Launch realsense2_camera node."""
+import copy
+from launch import LaunchDescription, LaunchContext
+import launch_ros.actions
+from launch.actions import IncludeLaunchDescription, OpaqueFunction
+from launch.substitutions import LaunchConfiguration, ThisLaunchFileDir
+from launch.launch_description_sources import PythonLaunchDescriptionSource
+import sys
+import pathlib
+sys.path.append(str(pathlib.Path(__file__).parent.absolute()))
+import rs_launch
+
+local_parameters = [{'name': 'camera_name1', 'default': 'camera1', 'description': 'camera1 unique name'},
+                    {'name': 'camera_name2', 'default': 'camera2', 'description': 'camera2 unique name'},
+                    {'name': 'camera_namespace1', 'default': 'camera1', 'description': 'camera1 namespace'},
+                    {'name': 'camera_namespace2', 'default': 'camera2', 'description': 'camera2 namespace'},
+                    {'name': 'depth_module.inter_cam_sync_mode1', 'default': '1', 'description': 'master'},
+                    {'name': 'depth_module.inter_cam_sync_mode2', 'default': '2', 'description': 'slave'},
+                    ]
+
+
+def set_configurable_parameters(local_params):
+    return dict([(param['original_name'], LaunchConfiguration(param['name'])) for param in local_params])
+
+def duplicate_params(general_params, posix):
+    local_params = copy.deepcopy(general_params)
+    for param in local_params:
+        param['original_name'] = param['name']
+        param['name'] += posix
+    return local_params
+
+def launch_static_transform_publisher_node(context : LaunchContext):
+    # dummy static transformation from camera1 to camera2
+    node = launch_ros.actions.Node(
+            package = "tf2_ros",
+            executable = "static_transform_publisher",
+            arguments = ["0", "0", "0", "0", "0", "0",
+                          context.launch_configurations['camera_name1'] + "_link",
+                          context.launch_configurations['camera_name2'] + "_link"]
+    )
+    return [node]
+
+def generate_launch_description():
+    params1 = duplicate_params(rs_launch.configurable_parameters, '1')
+    params2 = duplicate_params(rs_launch.configurable_parameters, '2')
+    return LaunchDescription(
+        rs_launch.declare_configurable_parameters(local_parameters) +
+        rs_launch.declare_configurable_parameters(params1) +
+        rs_launch.declare_configurable_parameters(params2) +
+        [
+        OpaqueFunction(function=rs_launch.launch_setup,
+                       kwargs = {'params'           : set_configurable_parameters(params1),
+                                 'param_name_suffix': '1'}),
+        OpaqueFunction(function=rs_launch.launch_setup,
+                       kwargs = {'params'           : set_configurable_parameters(params2),
+                                 'param_name_suffix': '2'}),
+        OpaqueFunction(function=launch_static_transform_publisher_node)
+    ])