Ros2 self study notes: rviz visualization tool

start-up rviz

ros2 run rviz2 rviz2

rviz Subscribe to other node topics , Get data , And render the data as an image . stay add Keyhole rviz Many common robot topics have been provided

rviz Display camera picture ：
First, in the gazebo Create camera module in

<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="camera">

    <xacro:macro name="usb_camera" params="prefix:=camera">
        <!-- Create laser reference frame -->
        <link name="${prefix}_link">
            <inertial>
                <mass value="0.1" />
                <origin xyz="0 0 0" />
                <inertia ixx="0.01" ixy="0.0" ixz="0.0"
                         iyy="0.01" iyz="0.0"
                         izz="0.01" />
            </inertial>

            <visual>
                <origin xyz=" 0 0 0 " rpy="0 0 0" />
                <geometry>
                    <box size="0.01 0.04 0.04" />
                </geometry>
                <material name="black"/>
            </visual>

            <collision>
                <origin xyz="0.0 0.0 0.0" rpy="0 0 0" />
                <geometry>
                    <box size="0.01 0.04 0.04" />
                </geometry>
            </collision>
        </link>
        <gazebo reference="${prefix}_link">
            <material>Gazebo/Black</material>
        </gazebo>

        <gazebo reference="${prefix}_link">
            <sensor type="camera" name="camera_node">
                <update_rate>30.0</update_rate>
                <camera name="head">
                    <horizontal_fov>1.3962634</horizontal_fov>
                    <image>
                        <width>1280</width>
                        <height>720</height>
                        <format>R8G8B8</format>
                    </image>
                    <clip>
                        <near>0.02</near>
                        <far>300</far>
                    </clip>
                    <noise>
                        <type>gaussian</type>
                        <mean>0.0</mean>
                        <stddev>0.007</stddev>
                    </noise>
                </camera>
                <plugin name="gazebo_camera" filename="libgazebo_ros_camera.so">
				    <ros>
				        <!-- <namespace>stereo</namespace> -->
				        <remapping>~/image_raw:=image_raw</remapping>
				        <remapping>~/camera_info:=camera_info</remapping>
				    </ros>
				    <camera_name>${
    prefix}</camera_name>
				    <frame_name>${
    prefix}_link</frame_name>
				    <hack_baseline>0.2</hack_baseline>
                </plugin>
            </sensor>
        </gazebo>

    </xacro:macro>
</robot>

1 <xacro:macro name="usb_camera" params="prefix:=camera">
Macro definition camera module , name usb_camera, Parameters prefix（ Used to complete the name ）

2

<visual>
   <origin xyz=" 0 0 0 " rpy="0 0 0" />
   <geometry>
       <box size="0.01 0.04 0.04" />
   </geometry>
   <material name="black"/>
</visual>

Set the appearance and position of the camera , Box type , black

3 <sensor type="camera" name="camera_node">
Core functions , Set camera properties .sensor Labels are used to identify sensors , The type here is camera

4 <update_rate>30.0</update_rate>
Update rate 30

5 <image> <width>1280</width> <height>720</height> <format>R8G8B8</format> </image>
Set the camera picture width 1280, high 720, Color space type R8G8B8

6 <clip> <near>0.02</near> <far>300</far> </clip>
The upper limit of camera shooting distance 300, Lower limit 0.02
7 <noise> <type>gaussian</type> <mean>0.0</mean> <stddev>0.007</stddev> </noise>
There may be noise in the picture taken by the real camera , This simulates noise

8

<plugin name="gazebo_camera" filename="libgazebo_ros_camera.so">
				    <ros>
				        <!-- <namespace>stereo</namespace> -->
				        <remapping>~/image_raw:=image_raw</remapping>
				        <remapping>~/camera_info:=camera_info</remapping>
				    </ros>
				    <camera_name>${
    prefix}</camera_name>
				    <frame_name>${
    prefix}_link</frame_name>
				    <hack_baseline>0.2</hack_baseline>
                </plugin>

Call the camera driver libgazebo_ros_camera.so, You can redirect the topic name to your own name

Merge the camera with the car body

<?xml version="1.0"?>
<robot name="arm" xmlns:xacro="http://www.ros.org/wiki/xacro">

    <xacro:include filename="$(find learning_gazebo)/urdf/mbot_base_gazebo.xacro" />
    <xacro:include filename="$(find learning_gazebo)/urdf/sensors/camera_gazebo.xacro" />

    <xacro:property name="camera_offset_x" value="0.17" />
    <xacro:property name="camera_offset_y" value="0" />
    <xacro:property name="camera_offset_z" value="0.10" />

    <!-- Camera -->
    <joint name="camera_joint" type="fixed">
        <origin xyz="${camera_offset_x} ${camera_offset_y} ${camera_offset_z}" rpy="0 0 0" />
        <parent link="base_link"/>
        <child link="camera_link"/>
    </joint>

    <xacro:usb_camera prefix="camera"/>

    <xacro:mbot_base_gazebo/>

</robot>

1 Introduction of camera and car body xacro Model

 <xacro:include filename="$(find learning_gazebo)/urdf/mbot_base_gazebo.xacro" />
<xacro:include filename="$(find learning_gazebo)/urdf/sensors/camera_gazebo.xacro" />

2

<xacro:property name="camera_offset_x" value="0.17" />
<xacro:property name="camera_offset_y" value="0" />
<xacro:property name="camera_offset_z" value="0.10" />

Set camera position

3

<joint name="camera_joint" type="fixed">
        <origin xyz="${camera_offset_x} ${camera_offset_y} ${camera_offset_z}" rpy="0 0 0" />
        <parent link="base_link"/>
        <child link="camera_link"/>
    </joint>

Use one joint Connect the camera to the body

stay rviz It shows the results
operation ：add->image-> stay topic Select the topic name released by the camera

notes ：gazebo and rviz difference
gazebo For the simulation platform , It can be used when there is no physical robot gazebo Simulate robot environment
rviz Display platform for , It can display the obtained two-dimensional or three-dimensional information , The data source can be gazebo It can also be in other ways