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The ZED2

The ZED2 is the main camera we use. In addition to being a camera, it has sensors as an IMU, gyroscope, magnetometer and other sensors. The ZED2 is also capable of producing a pose estimate of where it is in the world using the aforementioned sensors.

zed2

Some links:

The SDK you use to interface directly with the ZED2 is called the stereolabs SDK.

Known Issues with the ZED2

USB Connecton Issues

Modern ZED camera models have removable USB C plugs. The ZED1 and ZED2 do not have this kind of plug which means that the connection extremely flaky as the connector is constantly bending when mounting / unmounting / motion and it cannot be removed. The effects of this include:

  • Camera rebooting when the cable is touched / requring a very specific and static wire orientation to get anything to work.
  • The camera staying on for a few seconds before rebooting and not recovering from the corruption that required the reboot.

If you want to invest in a new ZED camera, invest in a newer ZED model such as the ZED2i that has a removable USB C cable.

Resolving USB Connection Issues

The only solution seems to be to follow this instructables article.

Using the ZED2

Compiling the ZED ROS2 Wrapper

The ZED ROS2 Wrapper is a suite of packages that make the sensors on the ZED2 available through a ROS2 interface. The following is a guide on how to compile these packages. The wrapper requires an NVIDIA GPU to operate -- the following is not applicable to platforms that don't have an NVIDIA GPU or whose drivers aren't working.

If you are using a shared platform such as the Jetson somebody has probably compiled the wrapper already. In this case you can skip to the sourcing step. Otherwise you can continue.

As prerequisites, in addition ros-humble desktop, you must install the fllowing packages:

ros-humble-nmea-msgs ros-humble-geographic-msgs ros-humble-diagnostic-updater ros-humble-robot-localization ros-humble-xacro ros-humble-zed-msgs

Clone the github repository ZED2 ROS Wrapper and the ZED2 Interfaces Repo:

git clone --recurse-submodules https://github.com/stereolabs/zed-ros2-wrapper
git -C zed-ros2-wrapper checkout f88bb492fa01754365f0ac0d56e70fd29d55bbee
git clone --recurse-submodules https://github.com/stereolabs/zed-ros2-interfaces
git -C zed-ros2-interfaces checkout 417073fce8adf398f7295ec25148a046aeb0eed6

Note: If you are still using ROS2 galactic, comment out the lines in zed_camera_component.cpp that trigger an error if the ROS version is not IRON or HUMBLE or FOXY. As of [2024-01-21 Sun], the main branch on github compiles fine under galactic. Otherwise, you can ignore this disclaimer.

Navigate to the zed-ros2-wrapper folder and build:

. /opt/ros/humble/setup.bash
colcon build --symlink-install
. install/setup.bash

Ensuring You Have Access to the Camera Device

First you need to ensure that you have access to the camera device. On linux, cameras are represented on the filesystem through the files /dev/videoN (where N is a number). By default, these are owned by the root user and the video group. You can check what groups your current user is in using the groups command. If you are not in the video group, add yourself to the group using the following command, replacing USER with your username.

sudo usermod -aG video USER

Another quick fix to this issue is simply changing the permissions on the video files such that everybody can access those files:

sudo chmod a+rw /dev/video*

Running the ZED2 ROS wrapper

After sourcing, you can run the wrapper as follows:

ros2 launch zed_wrapper zed2.launch.py camera_model:=zed2

Use ros2 topic list to explore the topics being published and use ros2 topic info TOPIC to view information about the topic types. To view information about a ROS2 topic type, use ros2 interface show INTERFACE.

Visualising the Camera Output

{% image src="https://github.com/stereolabs/zed-ros2-wrapper/raw/master/images/sim_rviz.jpg" width="450px" /%}

Source your ROS workspace. Then download this example RVIZ config and then run the following:

rviz2 -d zed_stereo.rviz

See also:

Multi Camera Setup

the zed2.launch.py script takes as arguments camera_name and serial_number which are relevant in a multi camera setup.

'camera_name':
        The name of the camera. It can be different from the camera model and it
        will be used as node `namespace`.
        (default: 'zed')

'serial_number':
        The serial number of the camera to be opened. It is mandatory to use this
        parameter in multi-camera rigs to distinguish between different cameras.
        (default: '0')

The zed2 with the sticker has serial number is 25382294 and the zed2 without a sticker is 23038477. So essentially, in two separate terminals, you execute the zed ros2 wrapper as:

ros2 launch zed_wrapper zed2.launch.py camera_name=zedA serial_number:=25382294

and

ros2 launch zed_wrapper zed2.launch.py camera_name=zedB serial_number:=23038477