There is still no example of two cameras for ROS2? no launch file

[adricort]

I am trying to do an application with 3 realsense cameras, but I haven't found yet a solution for the remappings in ROS2. Is is possible?

[matlabbe]

Yes, it should be possible. Is odometry computed externally?

Here two examples, assuming using Depth-IR mode for realsense (IR emitter disabled). Make sure rtabmap_ros is built with DRTABMAP_SYNC_MULTI_RGBD:

colcon build --symlink-install --cmake-args -DRTABMAP_SYNC_MULTI_RGBD=ON -DCMAKE_BUILD_TYPE=Release

With external odometry:

from launch import LaunchDescription
from launch_ros.actions import Node

def generate_launch_description():

    return LaunchDescription([

        Node(
            package='rtabmap_sync', executable='rgbd_sync', name='rgbd_sync1', output='screen',
            namespace='/realsense_camera1',
            parameters=[{'approx_sync':False}],
            remappings=[('rgb/image',       'infra1/image_rect_raw'),
                        ('rgb/camera_info', 'infra1/camera_info'),
                        ('depth/image',     'depth/image_rect_raw')]),
        
        Node(
            package='rtabmap_sync', executable='rgbd_sync', name='rgbd_sync2', output='screen',
            namespace='/realsense_camera2',
            parameters=[{'approx_sync':False}],
            remappings=[('rgb/image',       'infra1/image_rect_raw'),
                        ('rgb/camera_info', 'infra1/camera_info'),
                        ('depth/image',     'depth/image_rect_raw')]),

        Node(
            package='rtabmap_slam', executable='rtabmap', output='screen',
            parameters=[{'approx_sync':True, 'subscribe_rgbd':True, 'rgbd_cameras':2}],
            remappings=[('rgbd_image0',     '/realsense_camera1/rgbd_image'),
                        ('rgbd_image1',     '/realsense_camera2/rgbd_image'),
                        ('odom',            '/odom')],
            arguments=['-d']),
    ])

With RTAB-Map's visual odometry:

from launch import LaunchDescription
from launch_ros.actions import Node

def generate_launch_description():

    return LaunchDescription([

        Node(
            package='rtabmap_sync', executable='rgbd_sync', name='rgbd_sync1', output='screen',
            namespace='/realsense_camera1',
            parameters=[{'approx_sync':False}],
            remappings=[('rgb/image',       'infra1/image_rect_raw'),
                        ('rgb/camera_info', 'infra1/camera_info'),
                        ('depth/image',     'depth/image_rect_raw')]),
        
        Node(
            package='rtabmap_sync', executable='rgbd_sync', name='rgbd_sync2', output='screen',
            namespace='/realsense_camera2',
            parameters=[{'approx_sync':False}],
            remappings=[('rgb/image',       'infra1/image_rect_raw'),
                        ('rgb/camera_info', 'infra1/camera_info'),
                        ('depth/image',     'depth/image_rect_raw')]),
        
        Node(
            package='rtabmap_odom', executable='rgbd_odometry', output='screen',
            parameters=[{'approx_sync':True, 'subscribe_rgbd':True, 'rgbd_cameras':2}],
            remappings=[('rgbd_image0',     '/realsense_camera1/rgbd_image'),
                        ('rgbd_image1',     '/realsense_camera2/rgbd_image')]),

        Node(
            package='rtabmap_slam', executable='rtabmap', output='screen',
            parameters=[{'approx_sync':True, 'subscribe_rgbd':True, 'rgbd_cameras':1}],
            remappings=[('rgbd_image',     'rgbd_image'),
                        ('odom',           'odom_rgbd_image')],
            arguments=['-d']),
    ])

Note that in this example the realsense cameras would be started in different namespaces. You should also provide TF between the cameras and/or base frame of the robot.

[adricort]

Thanks for the reply!
I have been trying many many things in the last 5 hours, using as a reference the functional launch file for 1 camera (trying to adapt it to two cameras) and your solution above. I couldn't make it work.

This is my rtabmap_2cam.launch.py:

#
# To avoid log buffering:
# "stdbuf -o L ros2 launch rtabmap_launch rtabmap.launch.py ..."
#

import os

from launch import LaunchDescription, Substitution, LaunchContext
from launch.actions import DeclareLaunchArgument, SetEnvironmentVariable, LogInfo, OpaqueFunction
from launch.substitutions import LaunchConfiguration, ThisLaunchFileDir, PythonExpression
from launch.conditions import IfCondition, UnlessCondition
from launch_ros.actions import Node
from launch_ros.actions import SetParameter
from typing import Text
from ament_index_python.packages import get_package_share_directory

#Based on https://answers.ros.org/question/363763/ros2-how-best-to-conditionally-include-a-prefix-in-a-launchpy-file/
class ConditionalText(Substitution):
    def __init__(self, text_if, text_else, condition):
        self.text_if = text_if
        self.text_else = text_else
        self.condition = condition

    def perform(self, context: 'LaunchContext') -> Text:
        if self.condition == True or self.condition == 'true' or self.condition == 'True':
            return self.text_if
        else:
            return self.text_else
            
class ConditionalBool(Substitution):
    def __init__(self, text_if, text_else, condition):
        self.text_if = text_if
        self.text_else = text_else
        self.condition = condition

    def perform(self, context: 'LaunchContext') -> bool:
        if self.condition:
            return self.text_if
        else:
            return self.text_else
            
def launch_setup(context, *args, **kwargs):      
               
    return [
        DeclareLaunchArgument('depth', default_value=ConditionalText('false', 'true', IfCondition(PythonExpression(["'", LaunchConfiguration('stereo'), "' == 'true'"]))._predicate_func(context)), description=''),
        DeclareLaunchArgument('subscribe_rgb', default_value=LaunchConfiguration('depth'), description=''),
        DeclareLaunchArgument('args',  default_value=LaunchConfiguration('rtabmap_args'), description='Can be used to pass RTAB-Map\'s parameters or other flags like --udebug and --delete_db_on_start/-d'),
        DeclareLaunchArgument('qos_image',       default_value=LaunchConfiguration('qos'), description='Specific QoS used for image input data: 0=system default, 1=Reliable, 2=Best Effort.'),
        DeclareLaunchArgument('qos_camera_info', default_value=LaunchConfiguration('qos'), description='Specific QoS used for camera info input data: 0=system default, 1=Reliable, 2=Best Effort.'),
        DeclareLaunchArgument('qos_odom',        default_value=LaunchConfiguration('qos'), description='Specific QoS used for odometry input data: 0=system default, 1=Reliable, 2=Best Effort.'),
        DeclareLaunchArgument('qos_user_data',   default_value=LaunchConfiguration('qos'), description='Specific QoS used for user input data: 0=system default, 1=Reliable, 2=Best Effort.'),
    
        SetParameter(name='use_sim_time', value=LaunchConfiguration('use_sim_time')),
        # 'use_sim_time' will be set on all nodes following the line above
    
        # Relays RGB-Depth
        Node(
            package='image_transport', executable='republish', name='republish_rgb1',
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('stereo'), "' != 'true' and ('", LaunchConfiguration('subscribe_rgbd'), "' != 'true' or '", LaunchConfiguration('rgbd_sync'),"'=='true') and '", LaunchConfiguration('compressed'), "' == 'true'"])),
            remappings=[
                (['in/', LaunchConfiguration('rgb_image_transport')], [LaunchConfiguration('rgb_topic1'), '/', LaunchConfiguration('rgb_image_transport')]),
                ('out', LaunchConfiguration('rgb_topic1'))], 
            arguments=[LaunchConfiguration('rgb_image_transport'), 'raw'],
            namespace='realsense_camera1'),
        Node(
            package='image_transport', executable='republish', name='republish_rgb2',
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('stereo'), "' != 'true' and ('", LaunchConfiguration('subscribe_rgbd'), "' != 'true' or '", LaunchConfiguration('rgbd_sync'),"'=='true') and '", LaunchConfiguration('compressed'), "' == 'true'"])),
            remappings=[
                (['in/', LaunchConfiguration('rgb_image_transport')], [LaunchConfiguration('rgb_topic2'), '/', LaunchConfiguration('rgb_image_transport')]),
                ('out', LaunchConfiguration('rgb_topic2'))], 
            arguments=[LaunchConfiguration('rgb_image_transport'), 'raw'],
            namespace='realsense_camera2'),
        Node(
            package='image_transport', executable='republish', name='republish_depth1',
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('stereo'), "' != 'true' and ('", LaunchConfiguration('subscribe_rgbd'), "' != 'true' or '", LaunchConfiguration('rgbd_sync'),"'=='true') and '", LaunchConfiguration('compressed'), "' == 'true'"])),
            remappings=[
                (['in/', LaunchConfiguration('depth_image_transport')], [LaunchConfiguration('depth_topic1'), '/', LaunchConfiguration('depth_image_transport')]),
                ('out', LaunchConfiguration('depth_topic1'))], 
            arguments=[LaunchConfiguration('depth_image_transport'), 'raw'],
            namespace='realsense_camera1'),
        Node(
            package='image_transport', executable='republish', name='republish_depth2',
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('stereo'), "' != 'true' and ('", LaunchConfiguration('subscribe_rgbd'), "' != 'true' or '", LaunchConfiguration('rgbd_sync'),"'=='true') and '", LaunchConfiguration('compressed'), "' == 'true'"])),
            remappings=[
                (['in/', LaunchConfiguration('depth_image_transport')], [LaunchConfiguration('depth_topic2'), '/', LaunchConfiguration('depth_image_transport')]),
                ('out', LaunchConfiguration('depth_topic2'))], 
            arguments=[LaunchConfiguration('depth_image_transport'), 'raw'],
            namespace='realsense_camera2'),

        Node(
            package='rtabmap_sync', executable='rgbd_sync', name='rgbd_sync1', output="screen",
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('stereo'), "' != 'true' and '", LaunchConfiguration('rgbd_sync'), "' == 'true'"])),
            parameters=[{
                "approx_sync": False,
                "approx_sync_max_interval": LaunchConfiguration('approx_sync_max_interval'),
                "queue_size": LaunchConfiguration('queue_size'),
                "qos": LaunchConfiguration('qos_image'),
                "qos_camera_info": LaunchConfiguration('qos_camera_info'),
                "depth_scale": LaunchConfiguration('depth_scale')}],
            remappings=[
                ("rgb/image", LaunchConfiguration('rgb_topic1')),
                ("depth/image", LaunchConfiguration('depth_topic1')),
                ("rgb/camera_info", LaunchConfiguration('camera_info_topic1')),
                ("rgbd_image", LaunchConfiguration('rgbd_topic'))],
            namespace='/realsense_camera1'),
        Node(
            package='rtabmap_sync', executable='rgbd_sync', name='rgbd_sync2', output="screen",
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('stereo'), "' != 'true' and '", LaunchConfiguration('rgbd_sync'), "' == 'true'"])),
            parameters=[{
                "approx_sync": False,
                "approx_sync_max_interval": LaunchConfiguration('approx_sync_max_interval'),
                "queue_size": LaunchConfiguration('queue_size'),
                "qos": LaunchConfiguration('qos_image'),
                "qos_camera_info": LaunchConfiguration('qos_camera_info'),
                "depth_scale": LaunchConfiguration('depth_scale')}],
            remappings=[
                ("rgb/image", LaunchConfiguration('rgb_topic2')),
                ("depth/image", LaunchConfiguration('depth_topic2')),
                ("rgb/camera_info", LaunchConfiguration('camera_info_topic2')),
                ("rgbd_image", LaunchConfiguration('rgbd_topic'))],
            namespace='/realsense_camera2'),
            
        # Relay rgbd_image
        Node(
            package='rtabmap_util', executable='rgbd_relay', output="screen",
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('rgbd_sync'), "' != 'true' and '", LaunchConfiguration('subscribe_rgbd'), "' == 'true' and '", LaunchConfiguration('compressed'), "' != 'true'"])),
            remappings=[
                ("rgbd_image", LaunchConfiguration('rgbd_topic'))],
            namespace=LaunchConfiguration('namespace')),
        Node(
            package='rtabmap_util', executable='rgbd_relay', output="screen",
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('rgbd_sync'), "' != 'true' and '", LaunchConfiguration('subscribe_rgbd'), "' == 'true' and '", LaunchConfiguration('compressed'), "' == 'true'"])),
            parameters=[{
                "uncompress": True,
                "qos": LaunchConfiguration('qos_image')}],
            remappings=[
                ("rgbd_image", [LaunchConfiguration('rgbd_topic'), "/compressed"]),
                ([LaunchConfiguration('rgbd_topic'), "/compressed_relay"], LaunchConfiguration('rgbd_topic'))],
            namespace=LaunchConfiguration('namespace')),
                
        # RGB-D odometry
        Node(
            package='rtabmap_odom', executable='rgbd_odometry', output="screen",
            condition=IfCondition(PythonExpression(["'", LaunchConfiguration('icp_odometry'), "' != 'true' and '", LaunchConfiguration('visual_odometry'), "' == 'true' and '", LaunchConfiguration('stereo'), "' != 'true'"])),
            parameters=[{
                "rgbd_cameras":2,
                "frame_id": LaunchConfiguration('frame_id'),
                "odom_frame_id": LaunchConfiguration('vo_frame_id'),
                "publish_tf": LaunchConfiguration('publish_tf_odom'),
                "ground_truth_frame_id": LaunchConfiguration('ground_truth_frame_id').perform(context),
                "ground_truth_base_frame_id": LaunchConfiguration('ground_truth_base_frame_id').perform(context),
                "wait_for_transform": LaunchConfiguration('wait_for_transform'),
                "wait_imu_to_init": LaunchConfiguration('wait_imu_to_init'),
                "approx_sync": LaunchConfiguration('approx_sync'),
                "approx_sync_max_interval": LaunchConfiguration('approx_sync_max_interval'),
                "config_path": LaunchConfiguration('cfg').perform(context),
                "queue_size": LaunchConfiguration('queue_size'),
                "qos": LaunchConfiguration('qos_image'),
                "qos_camera_info": LaunchConfiguration('qos_camera_info'),
                "subscribe_rgbd": LaunchConfiguration('subscribe_rgbd'),
                "guess_frame_id": LaunchConfiguration('odom_guess_frame_id').perform(context),
                "guess_min_translation": LaunchConfiguration('odom_guess_min_translation'),
                "guess_min_rotation": LaunchConfiguration('odom_guess_min_rotation')}],
            remappings=[
                ("rgb/image", LaunchConfiguration('rgb_topic1')),
                ("depth/image", LaunchConfiguration('depth_topic1')),
                ("rgb/camera_info", LaunchConfiguration('camera_info_topic1')),
                ("rgbd_image0", '/realsense_camera1/rgbd_image'),
                ("rgbd_image1", '/realsense_camera2/rgbd_image'),
                ("odom", LaunchConfiguration('odom_topic'))],
            arguments=[LaunchConfiguration("args"), LaunchConfiguration("odom_args")],
            prefix=LaunchConfiguration('launch_prefix'),
            namespace=LaunchConfiguration('namespace')),

        Node(
            package='rtabmap_slam', executable='rtabmap', output="screen",
            parameters=[{
                "rgbd_cameras":1,
                "subscribe_depth": LaunchConfiguration('depth'),
                "subscribe_rgbd": LaunchConfiguration('subscribe_rgbd'),
                "subscribe_rgb": True,
                "subscribe_stereo": LaunchConfiguration('stereo'),
                "subscribe_user_data": LaunchConfiguration('subscribe_user_data'),
                "subscribe_odom_info": ConditionalBool(True, False, IfCondition(PythonExpression(["'", LaunchConfiguration('icp_odometry'), "' == 'true' or '", LaunchConfiguration('visual_odometry'), "' == 'true'"]))._predicate_func(context)).perform(context),
                "frame_id": LaunchConfiguration('frame_id'),
                "map_frame_id": LaunchConfiguration('map_frame_id'),
                "odom_frame_id": LaunchConfiguration('odom_frame_id').perform(context),
                "publish_tf": LaunchConfiguration('publish_tf_map'),
                "initial_pose": LaunchConfiguration('initial_pose'),
                "ground_truth_frame_id": LaunchConfiguration('ground_truth_frame_id').perform(context),
                "ground_truth_base_frame_id": LaunchConfiguration('ground_truth_base_frame_id').perform(context),
                "odom_tf_angular_variance": LaunchConfiguration('odom_tf_angular_variance'),
                "odom_tf_linear_variance": LaunchConfiguration('odom_tf_linear_variance'),
                "odom_sensor_sync": LaunchConfiguration('odom_sensor_sync'),
                "wait_for_transform": LaunchConfiguration('wait_for_transform'),
                "database_path": LaunchConfiguration('database_path'),
                "approx_sync": True,
                "config_path": LaunchConfiguration('cfg').perform(context),
                "queue_size": LaunchConfiguration('queue_size'),
                "qos_image": LaunchConfiguration('qos_image'),
                "qos_odom": LaunchConfiguration('qos_odom'),
                "qos_camera_info": LaunchConfiguration('qos_camera_info'),
                "qos_user_data": LaunchConfiguration('qos_user_data'),
                "Mem/IncrementalMemory": ConditionalText("true", "false", IfCondition(PythonExpression(["'", LaunchConfiguration('localization'), "' != 'true'"]))._predicate_func(context)).perform(context),
                "Mem/InitWMWithAllNodes": ConditionalText("true", "false", IfCondition(PythonExpression(["'", LaunchConfiguration('localization'), "' == 'true'"]))._predicate_func(context)).perform(context)
            }],
            remappings=[
                ("rgb/image", LaunchConfiguration('rgb_topic1')),
                ("depth/image", LaunchConfiguration('depth_topic1')),
                ("rgb/camera_info", LaunchConfiguration('camera_info_topic1')),
                ("rgbd_image", LaunchConfiguration('rgbd_topic')),
                ("left/image_rect", LaunchConfiguration('left_image_topic')),
                ("right/image_rect", LaunchConfiguration('right_image_topic')),
                ("left/camera_info", LaunchConfiguration('left_camera_info_topic')),
                ("right/camera_info", LaunchConfiguration('right_camera_info_topic')),
                ("user_data", LaunchConfiguration('user_data_topic')),
                ("user_data_async", LaunchConfiguration('user_data_async_topic')),
                ("odom", LaunchConfiguration('odom_topic'))],
            arguments=[LaunchConfiguration("args")],
            prefix=LaunchConfiguration('launch_prefix'),
            namespace=LaunchConfiguration('namespace')),

        Node(
            package='rtabmap_viz', executable='rtabmap_viz', output='screen',
            parameters=[{
                "subscribe_depth": LaunchConfiguration('depth'),
                "subscribe_rgbd": LaunchConfiguration('subscribe_rgbd'),
                "subscribe_rgb": LaunchConfiguration('subscribe_rgb'),
                "subscribe_stereo": LaunchConfiguration('stereo'),
                "subscribe_user_data": LaunchConfiguration('subscribe_user_data'),
                "subscribe_odom_info": ConditionalBool(True, False, IfCondition(PythonExpression(["'", LaunchConfiguration('icp_odometry'), "' == 'true' or '", LaunchConfiguration('visual_odometry'), "' == 'true'"]))._predicate_func(context)).perform(context),
                "frame_id": LaunchConfiguration('frame_id'),
                "odom_frame_id": LaunchConfiguration('odom_frame_id').perform(context),
                "wait_for_transform": LaunchConfiguration('wait_for_transform'),
                "approx_sync": LaunchConfiguration('approx_sync'),
                "queue_size": LaunchConfiguration('queue_size'),
                "qos_image": LaunchConfiguration('qos_image'),
                "qos_odom": LaunchConfiguration('qos_odom'),
                "qos_camera_info": LaunchConfiguration('qos_camera_info'),
                "qos_user_data": LaunchConfiguration('qos_user_data')
            }],
            remappings=[
                ("rgb/image", LaunchConfiguration('rgb_topic1')),
                ("depth/image", LaunchConfiguration('depth_topic1')),
                ("rgb/camera_info", LaunchConfiguration('camera_info_topic1')),
                ("rgbd_image", LaunchConfiguration('rgbd_topic')),
                ("left/image_rect", LaunchConfiguration('left_image_topic')),
                ("right/image_rect", LaunchConfiguration('right_image_topic')),
                ("left/camera_info", LaunchConfiguration('left_camera_info_topic')),
                ("right/camera_info", LaunchConfiguration('right_camera_info_topic')),
                ("odom", LaunchConfiguration('odom_topic'))],
            condition=IfCondition(LaunchConfiguration("rtabmapviz")),
            arguments=[LaunchConfiguration("gui_cfg")],
            prefix=LaunchConfiguration('launch_prefix'),
            namespace=LaunchConfiguration('namespace')),
        Node(
            package='rviz2', executable='rviz2', output='screen',
            condition=IfCondition(LaunchConfiguration("rviz")),
            arguments=[["-d"], [LaunchConfiguration("rviz_cfg")]]),
        Node(
            package='rtabmap_util', executable='point_cloud_xyzrgb', output='screen',
            condition=IfCondition(LaunchConfiguration("rviz")),
            parameters=[{
                "decimation": 4,
                "voxel_size": 0.0,
                "approx_sync": LaunchConfiguration('approx_sync'),
                "approx_sync_max_interval": LaunchConfiguration('approx_sync_max_interval')
            }],
            remappings=[
                ('left/image', LaunchConfiguration('left_image_topic')),
                ('right/image', LaunchConfiguration('right_image_topic')),
                ('left/camera_info', LaunchConfiguration('left_camera_info_topic')),
                ('right/camera_info', LaunchConfiguration('right_camera_info_topic')),
                ('rgb/image', LaunchConfiguration('rgb_topic1')),
                ('depth/image', LaunchConfiguration('depth_topic1')),
                ('rgb/camera_info', LaunchConfiguration('camera_info_topic1')),
                ('rgbd_image', LaunchConfiguration('rgbd_topic')),
                ('cloud', 'voxel_cloud')]),
        ]

def generate_launch_description():
    
    config_rviz = os.path.join(
        get_package_share_directory('rtabmap_launch'), 'launch', 'config', 'pC_rtabmap_2cameras.rviz'
    )
    
    return LaunchDescription([
        
        # Arguments
        DeclareLaunchArgument('stereo', default_value='false', description='Use stereo input instead of RGB-D.'),

        DeclareLaunchArgument('localization', default_value='false', description='Launch in localization mode.'),
        DeclareLaunchArgument('rtabmapviz',   default_value='false',  description='Launch RTAB-Map UI (optional).'),
        DeclareLaunchArgument('rviz',         default_value='false', description='Launch RVIZ (optional).'),

        DeclareLaunchArgument('use_sim_time', default_value='false', description='Use simulation (Gazebo) clock if true'),

        # Config files
        DeclareLaunchArgument('cfg',      default_value='',                        description='To change RTAB-Map\'s parameters, set the path of config file (*.ini) generated by the standalone app.'),
        DeclareLaunchArgument('gui_cfg',  default_value='~/.ros/rtabmap_gui.ini',  description='Configuration path of rtabmapviz.'),
        DeclareLaunchArgument('rviz_cfg', default_value=config_rviz,               description='Configuration path of rviz2.'),

        DeclareLaunchArgument('frame_id',       default_value='base_link',          description='Fixed frame id of the robot (base frame), you may set "base_link" or "base_footprint" if they are published. For camera-only config, this could be "camera_link".'),
        DeclareLaunchArgument('odom_frame_id',  default_value='',                   description='If set, TF is used to get odometry instead of the topic.'),
        DeclareLaunchArgument('map_frame_id',   default_value='map',                description='Output map frame id (TF).'),
        DeclareLaunchArgument('publish_tf_map', default_value='true',               description='Publish TF between map and odomerty.'),
        DeclareLaunchArgument('namespace',      default_value='rtabmap',            description=''),
        DeclareLaunchArgument('database_path',  default_value='~/.ros/rtabmap.db',  description='Where is the map saved/loaded.'),
        DeclareLaunchArgument('queue_size',     default_value='10',                 description=''),
        DeclareLaunchArgument('qos',            default_value='1',                  description='General QoS used for sensor input data: 0=system default, 1=Reliable, 2=Best Effort.'),
        DeclareLaunchArgument('wait_for_transform', default_value='0.2',            description=''),
        DeclareLaunchArgument('rtabmap_args',   default_value='',                   description='Backward compatibility, use "args" instead.'),
        DeclareLaunchArgument('launch_prefix',  default_value='',                   description='For debugging purpose, it fills prefix tag of the nodes, e.g., "xterm -e gdb -ex run --args"'),
        DeclareLaunchArgument('output',         default_value='screen',             description='Control node output (screen or log).'),
        DeclareLaunchArgument('initial_pose',   default_value='',                   description='Set an initial pose (only in localization mode). Format: "x y z roll pitch yaw" or "x y z qx qy qz qw". Default: see "RGBD/StartAtOrigin" doc'),
        
        DeclareLaunchArgument('ground_truth_frame_id',      default_value='', description='e.g., "world"'),
        DeclareLaunchArgument('ground_truth_base_frame_id', default_value='', description='e.g., "tracker", a fake frame matching the frame "frame_id" (but on different TF tree)'),
        
        DeclareLaunchArgument('approx_sync',  default_value='false',            description='If timestamps of the input topics should be synchronized using approximate or exact time policy.'),
        DeclareLaunchArgument('approx_sync_max_interval',  default_value='0.0', description='(sec) 0 means infinite interval duration (used with approx_sync=true)'),
        
        # Stereo related topics
        DeclareLaunchArgument('stereo_namespace',        default_value='/stereo_camera', description=''),
        DeclareLaunchArgument('left_image_topic',        default_value=[LaunchConfiguration('stereo_namespace'), '/left/image_rect_color'], description=''),
        DeclareLaunchArgument('right_image_topic',       default_value=[LaunchConfiguration('stereo_namespace'), '/right/image_rect'], description='Use grayscale image for efficiency'),
        DeclareLaunchArgument('left_camera_info_topic',  default_value=[LaunchConfiguration('stereo_namespace'), '/left/camera_info'], description=''),
        DeclareLaunchArgument('right_camera_info_topic', default_value=[LaunchConfiguration('stereo_namespace'), '/right/camera_info'], description=''),
        
        # Use Pre-sync RGBDImage format
        DeclareLaunchArgument('rgbd_sync',        default_value='false',      description='Pre-sync rgb_topic, depth_topic, camera_info_topic.'),
        DeclareLaunchArgument('approx_rgbd_sync', default_value='true',       description='false=exact synchronization.'),
        DeclareLaunchArgument('subscribe_rgbd',   default_value=LaunchConfiguration('rgbd_sync'), description='Already synchronized RGB-D related topic, e.g., with rtabmap_sync/rgbd_sync nodelet.'),
        DeclareLaunchArgument('rgbd_topic',       default_value='rgbd_image', description=''),
        DeclareLaunchArgument('depth_scale',      default_value='1.0',        description=''),
        
        # Image topic compression
        DeclareLaunchArgument('compressed',            default_value='false', description='If you want to subscribe to compressed image topics'),
        DeclareLaunchArgument('rgb_image_transport',   default_value='compressed', description='Common types: compressed, theora (see "rosrun image_transport list_transports")'),
        DeclareLaunchArgument('depth_image_transport', default_value='compressedDepth', description='Depth compatible types: compressedDepth (see "rosrun image_transport list_transports")'),
        
        # Odometry
        DeclareLaunchArgument('visual_odometry',            default_value='true',  description='Launch rtabmap visual odometry node.'),
        DeclareLaunchArgument('icp_odometry',               default_value='false', description='Launch rtabmap icp odometry node.'),
        DeclareLaunchArgument('odom_topic',                 default_value='odom',  description='Odometry topic name.'),
        DeclareLaunchArgument('vo_frame_id',                default_value=LaunchConfiguration('odom_topic'), description='Visual/Icp odometry frame ID for TF.'),
        DeclareLaunchArgument('publish_tf_odom',            default_value='true',  description=''),
        DeclareLaunchArgument('odom_tf_angular_variance',   default_value='0.01',    description='If TF is used to get odometry, this is the default angular variance'),
        DeclareLaunchArgument('odom_tf_linear_variance',    default_value='0.001',   description='If TF is used to get odometry, this is the default linear variance'),
        DeclareLaunchArgument('odom_args',                  default_value='',      description='More arguments for odometry (overwrite same parameters in rtabmap_args).'),
        DeclareLaunchArgument('odom_sensor_sync',           default_value='false', description=''),
        DeclareLaunchArgument('odom_guess_frame_id',        default_value='',      description=''),
        DeclareLaunchArgument('odom_guess_min_translation', default_value='0.0',   description=''),
        DeclareLaunchArgument('odom_guess_min_rotation',    default_value='0.0',   description=''),
        
        # User Data
        DeclareLaunchArgument('subscribe_user_data',   default_value='false',            description='User data synchronized subscription.'),
        DeclareLaunchArgument('user_data_topic',       default_value='/user_data',       description=''),
        DeclareLaunchArgument('user_data_async_topic', default_value='/user_data_async', description='User data async subscription (rate should be lower than map update rate).'),

        OpaqueFunction(function=launch_setup)
    ])

What is missing? I implemented almost everything I guess, but I can't just visualize the two mapClouds on Rviz. It says the rtabmap has not received anything, neither the rtabmap.rgbd_odometry:

[rgbd_odometry-3] [WARN] [1687276215.287419645] [rtabmap.rgbd_odometry]: rgbd_odometry: Did not receive data since 5 seconds! Make sure the input topics are published ("$ rostopic hz my_topic") and the timestamps in their header are set. 
[rgbd_odometry-3] rgbd_odometry subscribed to (exact sync):
[rgbd_odometry-3]    /realsense_camera1/rgbd_image,
[rgbd_odometry-3]    /realsense_camera2/rgbd_image
[point_cloud_xyzrgb-6] [INFO] [1687276215.287401018] [rclcpp]: signal_handler(signum=2)
[rviz2-5] [INFO] [1687276215.291123837] [rclcpp]: signal_handler(signum=2)
[rtabmap-4] [WARN] [1687276215.293313321] [rtabmap.rtabmap]: rtabmap: Did not receive data since 5 seconds! Make sure the input topics are published ("$ rostopic hz my_topic") and the timestamps in their header are set. If topics are coming from different computers, make sure the clocks of the computers are synchronized ("ntpdate"). If topics are not published at the same rate, you could increase "queue_size" parameter (current=10). 
[rtabmap-4] rtabmap subscribed to (approx sync):
[rtabmap-4]    /rtabmap/odom \
[rtabmap-4]    /rtabmap/rgbd_image \
[rtabmap-4]    /rtabmap/odom_info

Thank you!

[matlabbe]

Verify that /realsense_camera1/rgbd_image and /realsense_camera2/rgbd_image are both published with ros2 topic hz. If so, you would likely need to set approx_sync for rgbd_odometry to true (in your log you have exact sync for rgbd_odometry).

[adricort]

Hereby I confirm that this issue has been closed thanks to this pull request: #1002