Camera Sensor Lens Orthographic not working

[Jak253]

Hello,

I'm trying to use the camera sensor with the orthographic lens to generate a 2D map for navigation.
However, I can't change my lens type. It always stays stereographic.
Every value I write in the field is ignored.

The relevant SDF Parts look like this:
`

<physics type="ode">
  <max_step_size>0.003</max_step_size>
  <real_time_factor>1.0</real_time_factor>
</physics>
<plugin name="gz::sim::systems::Physics" filename="libgz-sim8-physics-system.so"/>
<plugin name="gz::sim::systems::UserCommands" filename="libgz-sim8-user-commands-system.so"/>
<plugin name="gz::sim::systems::SceneBroadcaster" filename="libgz-sim8-scene-broadcaster-system.so"/>
<plugin name="gz::sim::systems::Sensors" filename="libgz-sim8-sensors-system.so">
  <render_engine>ogre2</render_engine>
</plugin>

<model name="My_Ortho_Cam">
  <pose>170 -200 400 0 1.57 0</pose>
  <static>true</static>
  <link name="camera_link">
    <sensor name="my_camera" type="camera">
      <topic>/map_camera</topic>
      <update_rate>1</update_rate>
  <always_on>1</always_on>
      <visualize>true</visualize>
      <camera>
    <save enabled="true">
	    <path>/home/ros/camera</path>
        </save>
        <image>
          <width>10000</width>
          <height>10000</height>
          <format>R8G8B8</format>
        </image>
        <clip>
          <near>0.1</near>
          <far>1000</far>
        </clip>
    <lens>
          <type>orthographic</type>
    </lens>
      </camera>
    </sensor>
  </link>
</model>

`

I noticed that if I check my camera model with gz model -l -m My_Ortho_Cam -s all my properties are correctly set, except the lens type.
The output of said gz model -l -m My_Ortho_Cam -s
`
Requesting state for world [warehouse]...

• Link [5]
  • Name: camera_link
  • Parent: My_Ortho_Cam [4]
  • Mass (kg): 1.000000
  • Inertial Pose [ XYZ (m) ] [ RPY (rad) ]:
    [0.000000 0.000000 0.000000]
    [0.000000 -0.000000 0.000000]
  • Inertial Matrix (kg.m^2):
    [1.000000 0.000000 0.000000]
    [0.000000 1.000000 0.000000]
    [0.000000 0.000000 1.000000]
  • Pose [ XYZ (m) ] [ RPY (rad) ]:
    [0.000000 0.000000 0.000000]
    [0.000000 -0.000000 0.000000]
  • Sensor [6]
    • Name: my_camera
    • Parent: My_Ortho_Cam [4]
    • Pose [ XYZ (m) ] [ RPY (rad) ]:
      [0.000000 0.000000 0.000000]
      [0.000000 -0.000000 0.000000]
    • Horizontal field of view (rad): 1.047
    • Image width (px): 10000
    • Image height (px): 10000
    • Near clip (m): 0.1
    • Far clip (m): 1000
    • Pixel format: RGB_INT8
    • Save frames: 1
    • Save frames path: /home/ros/camera
    • Image noise:
      • Mean: 0
      • Bias mean: 0
      • Standard deviation: 0
      • Bias standard deviation: 0
      • Precision: 0
      • Dynamic bias standard deviation: 0
      • Dynamic bias correlation time (s): 0
    • Distortion K1: 0
    • Distortion K2: 0
    • Distortion K3: 0
    • Distortion P1: 0
    • Distortion P2: 0
    • Distortion center: 0.5 0.5
    • Lens type: stereographic
    • Lens scale to horizontal field of view (rad): 1
    • Lens C1: 1
    • Lens C2: 1
    • Lens C3: 0
    • Lens focal length (m): 1
    • Lens function: tan
    • Lens cutoff angle (rad): 1.5708
    • Lens texture size: 256
    • Lens intrinsics Fx: 277
    • Lens intrinsics Fy: 277
    • Lens intrinsics Cx: 160
    • Lens intrinsics Cy: 120
    • Lens intrinsics skew: 0
    • Visibility mask: 4294967295
      `

I'm unsure if it's because I did something wrong with the implementation of the SDF-file, or gazebo does not support different lens types, or the rendering engine does not support it.

Thanks for your help and input in advance.

[iche033]

we currently don't support setting a camera to orthographic projection from the sdf. The //lens/type sdf tag is currently only used by wide angle cameras but not regular cameras.

To support this, I think we would need to parse the //lens/type SDF element in CameraSensor::CreateCamera and set the projection type (by calling camera->SetProjectionType)

[Jak253]

Hello,

Thanks for the information!
I cloned the gz-sensor repository and made my changes. However, I can't get Gazebo to use my modified version.

Is there an easy way to integrate my changes in gz-sensor into Gazebo?

I have three options in mind, but I'm not sure which is the best or fastest one:

1. Clone gz-sensor, make changes, build it, and let Gazebo use my modified version instead of the default one.
2. Create a plugin, apply the changes there, and import the plugin in the SDF file.
3. Clone the entire gz-sim project along with all its submodules (gz-gui, gz-launch, etc.), modify gz-sensor, and rebuild Gazebo from scratch.
   I would prefer the first option if it's feasible since it seems to be the simplest approach.
   However, I couldn't find a guide on how to make Gazebo use a modified submodule like gz-sensor instead of the default version.

Could you maybe point me in the right direction?

[iche033]

you should be able to go with 1 in a colcon workspace

Clone and build gz-sensors:

mkdir -p ~/colcon_ws/src
cd ~/colcon_ws/src
git clone git@github.com:gazebosim/gz-sensors.git

# make your local changes then build
cd ~/colcon_ws
colcon build --merge-install

Source the workspace and run gz

cd ~/colcon_ws
. install/setup.bash
gz sim -v 4 <your_sdf_world>