8. Frequently Asked Questions

8.1. Unexpected Crash

If the camera node crashes unexpectedly, it will generate a crash log in the current running directory: ~/.ros/Log/camera_crash_stack_trace_xx.log. Additionally, regardless of whether the camera node crashes or not, the OrbbecSDK will always generate a log file: ~/.ros/Log/OrbbecSDK.log.txt, which contains detailed records of the SDK’s operations.

Please send these log files to the support team or submit them to a GitHub issue for further assistance.

8.2. 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.

8.3. Compilation Failure Due to OpenCV Version Issues

In some cases, you may have multiple versions of OpenCV on your host, which can lead to compilation failures. You can resolve this by specifying the OpenCV version. Find the CMakeLists.txt file in the cmake folder and locate the following code:

find_package(OpenCV REQUIRED)

Either add OpenCV_dir or specify the version before it:

find_package(OpenCV 4.2.0 REQUIRED)

Or:

set(OpenCV_DIR "/path_to_your_opencv_dir")
find_package(OpenCV REQUIRED)

8.4. Additional Troubleshooting

If you encounter other issues, set the log_level parameter to debug. This will generate an SDK log file in the running directory: ~/.ros/Log/OrbbecSDK.log.txt. Please provide this file to the support team for further assistance.
If firmware logs are required, set enable_heartbeat to true to activate this feature.

8.5. Why Are There So Many Launch Files?

Different cameras have varying default resolutions and image formats.
To simplify usage, each camera has its own launch file.

8.6. How to Launch a Specific Camera When Multiple Cameras Are Connected

While the launch file did not explicitly specify which device to use. In that case, the driver will connect to the default device.

You can check the serial number of your device by running:

rosrun orbbec_camera list_devices_node

Then launch with the serial number explicitly set, for example:

roslaunch orbbec_camera femto_bolt.launch serial_number:=CL8H741005J

8.7. Why Is It Necessary to Add Delays When Starting Multiple Cameras or Switching Streams?

Multi-camera systems place high demands on USB bandwidth and device initialization timing. If multiple camera streams are started or switched simultaneously, it may cause temporary bandwidth congestion, leading to device initialization failures, stream startup errors, or frame drops. To ensure system stability, the following practices are recommended:

Multi-camera startup phase

When starting multiple cameras, it is recommended to introduce an appropriate delay between each camera startup (e.g., 2 seconds) to avoid instantaneous bandwidth overload or low-level device initialization conflicts.
Stream enable/disable and mode switching phase

When invoking stream control services (such as set_streams_enable, toggle_depth, and toggle_color), avoid triggering multiple service calls at the same time. Instead, introduce a reasonable interval between operations (e.g., 20 ms) to ensure reliable stream state transitions.

Following these timing control guidelines can significantly improve the stability of multi-camera systems during startup and runtime, reducing errors and unexpected behavior.