# Start single camera

This guide provides instructions on how to launch the camera node with a colored point cloud feature enabled using ROS 2.

 

<!-- TOC -->

- Contents:
  - [Start single camera](#start-single-camera)
  - [Visualizing Data in RViz2](#visualizing-data-in-rviz2)
  - [Display view topics service](#display-view-topics-service)
  - [Example Visualizations](#example-visualizations)
  - [TF tree diagram](#tf-tree-diagram)

<!-- TOC -->

&nbsp;

## Start single camera

- Command to start single camera node

On terminal 1: Launch camera node, example of gemini_330 series :

```bash
cd ~/ros2_ws/
source /opt/ros/humble/setup.bash # or source /opt/ros/humble/setup.zsh
source install/setup.bash  # or source install/setup.szh
ros2 launch orbbec_camera orbbec_camera.launch.py config_file_path:=gemini_330_series.yaml
```

## Visualizing Data in RViz2

- To view the PointCloud or Image data, use RViz2:

On terminal 2: Launch rviz2

```bash
cd ~/ros2_ws/
source /opt/ros/humble/setup.bash # or source /opt/ros/humble/setup.zsh
source install/setup.bash    # or source install/setup.szh
rviz2         # run rviz2
```

- Select the topic you wish to visualize from the list of published topics.
- Add the selected topic to RViz2 to start viewing the data.

&nbsp;

## Display view topics service

Once the camera node is running, it will publish data on several ROS topics. Below is a list of the available topics:
By executing `ros2 topic list`, the following topics are displayed:

On terminal 3:

```bash
ros2 topic list
```

Other , to display services/ parameters , example as follow

```bash
ros2 service list
ros2 param list
```

Get device info:

```bash
ros2 service call /camera/get_device_info orbbec_camera_msgs/srv/GetDeviceInfo '{}'
```

Get SDK version:

```bash
ros2 service call /camera/get_sdk_version orbbec_camera_msgs/srv/GetString '{}'
```

Set auto exposure:

```bash
ros2 service call /camera/set_color_auto_exposure std_srvs/srv/SetBool '{data: false}'
```

Save point cloud:

```bash
ros2 service call /camera/save_point_cloud std_srvs/srv/Empty "{}"
```

&nbsp;

## Example Visualizations

Here are examples of how the visualization might appear in RViz2:

- **PointCloud Visualization**

![PointCloud View](../image/image1.jpg)

&nbsp;
- **Image Data Visualization**

![Image Data View](../image/image2.jpg)

&nbsp;

## TF tree diagram

To get the TF tree

```bash
ros2 run rqt_tf_tree rqt_tf_tree --force-discover
```

&nbsp;

The TF tree diagram for the OrbbecSDK_ROS2 is illustrated below:
![single_cam_tf.png](../image/single_cam_tf.png)