5.2.1. Multi-Camera

To get the usb_port of the camera, plug in the camera and run the following command in the terminal:

ros2 run orbbec_camera list_devices_node

Set the device_num parameter to the number of cameras you have.
Go to the OrbbecSDK_ROS2/launch/multi_xxx.launch.py file and change the usb_port.
Don’t forget to put the include tag inside the group tag. Otherwise, the parameter values of different cameras may become contaminated.

from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, IncludeLaunchDescription, GroupAction, ExecuteProcess
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch_ros.actions import Node
from ament_index_python.packages import get_package_share_directory
import os


def generate_launch_description():
    # Include launch files
    package_dir = get_package_share_directory('orbbec_camera')
    launch_file_dir = os.path.join(package_dir, 'launch')
    launch1_include = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            os.path.join(launch_file_dir, 'gemini2L.launch.py')
        ),
        launch_arguments={
            'camera_name': 'camera_01',
            'usb_port': '6-2.4.4.2',  # replace your usb port here
            'device_num': '2'
        }.items()
    )

    launch2_include = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            os.path.join(launch_file_dir, 'gemini2L.launch.py')
        ),
        launch_arguments={
            'camera_name': 'camera_02',
            'usb_port': '6-2.4.1',  # replace your usb port here
            'device_num': '2'
        }.items()
    )

    # If you need more cameras, just add more launch_include here, and change the usb_port and device_num

    # Launch description
    ld = LaunchDescription([
        GroupAction([launch1_include]),
        GroupAction([launch2_include]),
    ])

    return ld

To launch the cameras, run the following command:

ros2 launch orbbec_camera multi_camera.launch.py

5.2.1.1. No Data Stream from Multiple Cameras

Insufficient Power Supply:

Ensure that each camera is connected to a separate hub.
Use a powered hub to provide sufficient power to each camera.

High Resolution:

Try lowering the resolution to resolve data stream issues.

Increase usbfs_memory_mb Value:

Increase the usbfs_memory_mb value to 128MB (this is a reference value and can be adjusted based on your system’s needs) by running the following command:

    echo 128 | sudo tee /sys/module/usbcore/parameters/usbfs_memory_mb

To make this change permanent, check this link.

5.2.1.2. Image topic frame rate too low from Multiple Cameras

Refer to the Fast DDS Configuration file.