Top View Projection

[rabayjai112]

Hi @Martin-Oehler thank you for sharing

I have a question about a top view projection

My project have 3 pinhole camera and already calibrated.

I try to make a Top View Projection By use plugin PinholeProjection and this is my setting parameters

pinhole_front:
update_rate: 10
always_recompute_mapping: false
base_frame: front_camera
pose: [0, 0, 0, 0, 0, 0]
virtual_sensor_frame: pinhole_front_camera_frame
virtual_sensor_optical_frame: pinhole_front_optical_frame
projection_type: image_projection_plugins::PinholeProjection
projection_parameters:
image_width: 1280
image_height: 720
horizontal_fov: 0 # degree
focal_length: 1

Low Right view pinhole projection

pinhole_low_right:
update_rate: 10
always_recompute_mapping: false
base_frame: low_right_camera
pose: [0, 0, 0, 0, 0, 0]
virtual_sensor_frame: pinhole_low_right_camera_frame
virtual_sensor_optical_frame: pinhole_low_right_optical_frame
projection_type: image_projection_plugins::PinholeProjection
projection_parameters:
image_width: 1280
image_height: 720
horizontal_fov: 0
focal_length: 1

Low Left view pinhole projection

pinhole_low_left:
update_rate: 10
always_recompute_mapping: false
base_frame: low_left_camera
pose: [0, 0, 0, 0, 0, 0]
virtual_sensor_frame: pinhole_low_left_camera_frame
virtual_sensor_optical_frame: pinhole_low_left_optical_frame
projection_type: image_projection_plugins::PinholeProjection
projection_parameters:
image_width: 1280
image_height: 720
horizontal_fov: 0
focal_length: 1

The question is Does PinholeProjection Plugin can do Top-View projection?
If yes do i set parameters correctly?

Thanks You in advance

Kinds regards,
Chin

[Martin-Oehler]

Hello, thanks for your interest in my project.

Yes, as can be seen in my paper, the pinhole projection can be used as a top view. However, your configuration looks very strange. Why are you defining three projections? You should define one projection, that is above your robot and looks downwards. Also the horizontal_view parameter should not be zero. Otherwise, you won't see anything.

I think, you are mistakenly using the projection configuration to set up your cameras. This should be done in the camera configuration files, see here for example.

[rabayjai112]

Nice to meet you here. @Martin-Oehler
Yes you were right I made a mistake and a great thank for your advice.

After I make a virtual camera frame above my robot and looks downwards.
This is my setting in projection.yaml
pinhole_topview:
update_rate: 10
always_recompute_mapping: false
base_frame: top_camera
pose: [0, 0, 1, 0, 0, 0]
virtual_sensor_frame: pinhole_top_camera_frame
virtual_sensor_optical_frame: pinhole_top_optical_frame
projection_type: image_projection_plugins::PinholeProjection
projection_parameters:
image_width: 2560 #1280
image_height: 1440 #720
horizontal_fov: 90 # degree
focal_length: 10

I create a virtual camera frame 10 m. above from base_link that is why I set 10 at focal_length.

This is my setting in camera.yaml and TF of robot.
cameras:
- '/front'
- '/low_left'
- '/low_right'
/front:
image_topic: image_raw
camera_info_topic: camera_info
extended_camera_info_topic: extended_camera_info_not_used
/low_left:
image_topic: image_raw
camera_info_topic: camera_info
extended_camera_info_topic: extended_camera_info_not_used
/low_right:
image_topic: image_raw
camera_info_topic: camera_info
extended_camera_info_topic: extended_camera_info_not_used

The result show like this picture.

Picture from front camera project correctly but another 2 cameras isn't.

Do you have any idea which is the reason and how to configure this.

Thanks You in advance

Kinds regards,
Chin

[Martin-Oehler]

Sorry for the late reply, I somehow missed your update.

Your configuration looks fine so far. My first guess would be, that the urdf/tf or camera calibration for your two lower cameras is wrong. Can you verify, that they are correct?

You could also play around with the projection settings in rqt_reconfigure and see, if it changes anything.

If that doesn't help, I would ask you to upload a bag file with tf, camera images and calibration so I can check it out.

Best regards,
Martin