OrbbecSDK_ROS2/docs/multi_camera_syned.MD

Multi-camera synchronous image storage and script analysis

This section describes how to use multiple Orbbec cameras to store images synchronously in a ROS 2 environment and use scripts to parse the data.

Connection preparation

Please follow the instructions to connect multiple Orbbec cameras and Multi-Camera Sync Hub Pro.

• For detailed guidance on Multi-Camera Sync Hub Pro, you can refer to Set up cameras for external synchronization.
• Example of connecting multiple cameras to Multi-Camera Sync Hub Pro.

Multi-camera synchronous image storage

Check the USB port of your device

ros2 run orbbec_camera list_devices_node

Parameter configuration

multi_camera_synced.launch.py

1. usb_port is set to the USB port of the device.
2. device_num is set to 2, indicating that two cameras are started.
3. sync_mode is set to primary, indicating that the camera device is set to host mode.
4. The slave sets trigger_out_enabled to false.

multi_save_rgbir_params.json

Configure USB ports and names for multiple devices.

camera_params.yaml

Enable the left IR camera.

enable_left_ir: true

start_multi_sync.sh

{data: 100} means that each stream of each camera stores 100 images.

Running

Start multiple Orbbec cameras (select 1).

• On terminal 1

cd  ~/ros2_ws/src/OrbbecSDK_ROS2/orbbec_camera/tools
sudo chmod +x start_multi_sync.sh
bash start_multi_sync.sh

Save the image synchronously (select 4).

• On terminal 2

cd  ~/ros2_ws/src/OrbbecSDK_ROS2/orbbec_camera/tools
bash start_multi_sync.sh

Script parsing

multicamera_sync - save the image and analysis script storage directory.

• ouput - save the image directory
• Python - analysis script directory

Note: multicamera_sync needs to be copied to the current workspace directory (same level as the install directory).

Configuration Files

• Config.ini configures the camera's actual frame rate and maximum error timestamp threshold.
• DevicesInfo.txt configures the number of cameras and the camera's pid, vid, SN number and other parameters.
• StreamProfileInfo.txt configures the camera resolution, frame rate, and encoding format.

Note: DevicesInfo.txt and StreamProfileInfo.txt are files required by the parsing script and need to be copied to the same directory as the TotalModeFrames folder (The TotalModeFrames directory is created by the image saving script and is used to store image data collected synchronously by multiple cameras).

Running

Run the parsing script to parse the images stored synchronously by multiple cameras.

cd  ~/ros2_ws/multicamera_sync/Python
python3 SyncFramesMain.py

Output

• matchFrames: Incomplete dataset of the same camera group, camera image information is missing.
• notMatchFrames: Complete dataset of the same camera group.
• abnormal: The same set of complete data sets of cameras, and the camera synchronization time exceeds the parameter tspRangeThreshold set in Config.ini.