Skip to content

Camera

Bridge rgb camera between gazebo to ros

Tip

Check resource for detail gazebo ros bridge

bridge

image transport

coordinate system

Gazebo

sdf specification

Add sensor plugin to world

add sensor plugin to world
1
2
3
4
5
<plugin
  filename="gz-sim-sensors-system"
  name="gz::sim::systems::Sensors">
  <render_engine>ogre2</render_engine>
</plugin>
RGB Camera
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
  <gazebo reference="camera_link">
    <sensor name="camera" type="camera">
      <camera>
        <horizontal_fov>1.3962634</horizontal_fov>
        <image>
          <width>640</width>
          <height>480</height>
          <format>R8G8B8</format>
        </image>
        <clip>
          <near>0.1</near>
          <far>15</far>
        </clip>
        <noise>
          <type>gaussian</type>
          <!-- Noise is sampled independently per pixel on each frame.
               That pixel's noise value is added to each of its color
               channels, which at that point lie in the range [0,1]. -->
          <mean>0.0</mean>
          <stddev>0.007</stddev>
        </noise>
        <optical_frame_id>camera_link_optical</optical_frame_id>
        <camera_info_topic>camera/camera_info</camera_info_topic>
      </camera>
      <always_on>1</always_on>
      <update_rate>20</update_rate>
      <visualize>true</visualize>
      <topic>camera/image</topic>
    </sensor>
  </gazebo>

ROS2

check ros gz sim demo

Bridge

  • image_raw
  • image_info
gz_bridge.yaml
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
- ros_topic_name: "/camera/image_raw"
  gz_topic_name: "/camera/image_raw"
  ros_type_name: "sensor_msgs/msg/Image"
  gz_type_name: "gz.msgs.Image"
  direction: GZ_TO_ROS
# camera info
- ros_topic_name: "/camera/image_info"
  gz_topic_name: "/camera/image_info"
  ros_type_name: "sensor_msgs/msg/CameraInfo"
  gz_type_name: "gz.msgs.CameraInfo"
  direction: GZ_TO_ROS

ROS2 CV-Bridge

Image Transport

automatically compress the video stream in the background

launch
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
launch:
  - arg:
      name: use_sim_time
      default: "true"
      description: Use simulation (Gazebo) clock if true
  - node:
      pkg: "ros_gz_image"
      exec: "image_bridge"
      output: screen
      args:
          "/camera/image"
      param:
          - name: use_sim_time
            value : true
          - name: camera.image.compressed.jpeg_quality          
            value: 75
  # using topic_tools relay to republish camera_info topic
  - node:
      pkg: "topic_tools"
      exec: "relay"
      output: screen
      args:
          "'camera/camera_info' 'camera/image/camera_info'"
      param:
          - name: use_sim_time
            value : $(var use_sim_time)

TODO: configure and more

alt text

Coordinate system

  • camera link
  • camera optical link
  •  1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
      <joint type="fixed" name="camera_joint">
    <origin xyz="0.225 0 0.075" rpy="0 0 0"/>
    <child link="camera_link"/>
    <parent link="base_link"/>
    <axis xyz="0 1 0" />
  </joint>

  <link name='camera_link'>
    <pose>0 0 0 0 0 0</pose>
    <inertial>
      <mass value="0.1"/>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <inertia
          ixx="1e-6" ixy="0" ixz="0"
          iyy="1e-6" iyz="0"
          izz="1e-6"
      />
    </inertial>

    <collision name='collision'>
      <origin xyz="0 0 0" rpy="0 0 0"/> 
      <geometry>
        <box size=".03 .03 .03"/>
      </geometry>
    </collision>

    <visual name='camera_link_visual'>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <box size=".03 .03 .03"/>
      </geometry>
    </visual>

  </link>

  <gazebo reference="camera_link">
    <material>Gazebo/Red</material>
  </gazebo>

  <joint type="fixed" name="camera_optical_joint">
    <origin xyz="0 0 0" rpy="-1.5707 0 -1.5707"/>
    <child link="camera_link_optical"/>
    <parent link="camera_link"/>
  </joint>

  <link name="camera_link_optical">
  </link>

ros_gz_image

use image_transport

image transport bridge
1
sudo apt install ros-jazzy-ros-gz-image

1
ros2 run ros_gz_image image_bridge /camera/image_raw

rqt

1
ros2 run rqt_image_view rqt_image_view /camera/image_raw

alt text