Published CameraInfo does not contain correct information

[wittenator]

Environment

• OS Version: Ubuntu 22.04
• Source or binary build?
  Binary: Harmonic

Description

• Expected behavior: The camera info topic should correctly reflect the intrinsic properties of the camera
• Actual behavior: The camera info contains default values that do no get changed.

Steps to reproduce and output

1. Insert a camera sensor with non-default parameters e.g.

<sensor name="camera" type="camera">
          <gz_frame_id>camera_link_optical</gz_frame_id>
          <camera>
            <horizontal_fov>1.478294</horizontal_fov>
            <vertical_fov>1.153663</vertical_fov>
            <image>
              <width>640</width>
              <height>480</height>
            </image>
            <clip>
              <near>0.01</near>
              <far>60</far>
            </clip>
          </camera>
          <always_on>1</always_on>
          <update_rate>20</update_rate>
          <visualize>false</visualize>
        </sensor>

3. Subscribe to the /camera_info topic. This yields the following message:

header {
  stamp {
    sec: 47
  }
  data {
    key: "frame_id"
    value: "camera_link_optical"
  }
}
width: 640
height: 480
distortion {
  k: 0
  k: 0
  k: 0
  k: 0
  k: 0
}
intrinsics {
  k: 277
  k: 0
  k: 160
  k: 0
  k: 277
  k: 120
  k: 0
  k: 0
  k: 1
}
projection {
  p: 277
  p: 0
  p: 160
  p: 0
  p: 0
  p: 277
  p: 120
  p: 0
  p: 0
  p: 0
  p: 1
  p: 0
}
rectification_matrix: 1
rectification_matrix: 0
rectification_matrix: 0
rectification_matrix: 0
rectification_matrix: 1
rectification_matrix: 0
rectification_matrix: 0
rectification_matrix: 0
rectification_matrix: 1

The correct intrinsic matrix would look like this though:

[[351.05947319   0.         320.        ]
 [  0.         368.86247951 240.        ]
 [  0.           0.           1.        ]]

[azeey]

I'm not able to reproduce this. After removing vertical_fov, since it's not in the SDF spec, with gz-sim 8.2.0, I get:

header {
  stamp {
    sec: 49
    nsec: 300000000
  }
  data {
    key: "frame_id"
    value: "camera_link_optical"
  }
}
width: 640
height: 480
distortion {
  k: 0
  k: 0
  k: 0
  k: 0
  k: 0
}
intrinsics {
  k: 351.05941772460938
  k: 0
  k: 320
  k: 0
  k: 351.05941772460938
  k: 240
  k: 0
  k: 0
  k: 1
}
projection {
  p: 351.05941772460938
  p: 0
  p: 320
  p: 0
  p: 0
  p: 351.05941772460938
  p: 240
  p: 0
  p: 0
  p: 0
  p: 1
  p: 0
}
rectification_matrix: 1
rectification_matrix: 0
rectification_matrix: 0
rectification_matrix: 0
rectification_matrix: 1
rectification_matrix: 0
rectification_matrix: 0
rectification_matrix: 0
rectification_matrix: 1

[wittenator]

Oh wow, I don't know where I got this property from. Thanks for the quick fix! I assume that the vertical fov is computed via the horizontal fov and the image width and height given that the virtual sensor has quadratic pixels?

[azeey]

I wasn't able to reproduce the issue even with <vertical_fov> in there. I just thought I would mention it.

I assume that the vertical fov is computed via the horizontal fov and the image width and height given that the virtual sensor has quadratic pixels?

I believe the vertical fov is determined by the horizontal fov and the aspect ratio (see https://gazebosim.org/api/rendering/8/classgz_1_1rendering_1_1Camera.html#adc6fc0b99e5c81f89408f0a69693f155), which is set to width/height:

gz-sensors/src/CameraSensor.cc

Line 257 in 27239b4

this->dataPtr->camera->SetAspectRatio(static_cast<double>(width)/height);

I'll go ahead and close this issue since it doesn't appear to be a bug in gz-sensors