apriltag-ros : tag detected but no messages in /tag-detections
Hi,
I installed apriltag_ros using apt (sudo apt ros-melodic-apriltag-ros).
The detection seem to work fine (tags are well detected in the /tag_detections_image topic, and are correctly published to the /tf topic).
However, there seem to be no data published to the /tag_detections topic (which I would like to use to get the covariance of the pose).
Do you have an idea what might be the issue?
OS : ubuntu 18.04
Ros distribution : melodic
launch file :
<launch>
<arg name="launch_prefix" default="" /> <!-- set to value="gdbserver localhost:10000" for remote debugging -->
<arg name="node_namespace" default="apriltag_ros_continuous_node" />
<arg name="camera_name" default="/zed2/zed_node/left" />
<arg name="camera_frame" default="zed2_left_camera_frame" />
<arg name="image_topic" default="image_rect_color" />
<!-- Set parameters -->
<rosparam command="load" file="$(find borobo)/params/april_tags/settings.yaml" ns="$(arg node_namespace)" />
<rosparam command="load" file="$(find borobo)/params/april_tags/tags.yaml" ns="$(arg node_namespace)" />
<node pkg="apriltag_ros" type="apriltag_ros_continuous_node" name="$(arg node_namespace)" clear_params="true" output="screen" launch-prefix="$(arg launch_prefix)" >
<!-- Remap topics from those used in code to those on the ROS network -->
<remap from="image_rect" to="$(arg camera_name)/$(arg image_topic)" />
<remap from="camera_info" to="$(arg camera_name)/camera_info" />
<param name="camera_frame" type="str" value="$(arg camera_frame)" />
<param name="publish_tag_detections_image" type="bool" value="true" /> <!-- default: false -->
</node>
</launch>
settings.yaml :
# AprilTag 3 code parameters
# Find descriptions in apriltag/include/apriltag.h:struct apriltag_detector
# apriltag/include/apriltag.h:struct apriltag_family
tag_family: 'tag36h11' # options: tagStandard52h13, tagStandard41h12, tag36h11, tag25h9, tag16h5, tagCustom48h12, tagCircle21h7, tagCircle49h12
tag_border: 1 # default: 1
tag_threads: 2 # default: 2
tag_decimate: 1.0 # default: 1.0
tag_blur: 0.0 # default: 0.0
tag_refine_edges: 1 # default: 1
tag_debug: 0 # default: 0
# Other parameters
publish_tf: true # default: false
tags.yaml:
# # Definitions of tags to detect
# ### Syntax
#
# standalone_tags:
# [
# {id: ID, size: SIZE, name: NAME},
# ...
# ]
standalone_tags:
[
{id: 0, size: 0.121, name: TAG_0},
{id: 1, size: 0.121, name: TAG_1},
{id: 2, size: 0.121, name: TAG_2}
]
tag_bundles:
[
]
And because I have seen a few problems related to it (even if it doesn't seem to be my casse), I also add a sample output from the camera-info topic:
header:
seq: 91989
stamp:
secs: 1601390207
nsecs: 372746857
frame_id: "zed2_left_camera_optical_frame"
height: 720
width: 1280
distortion_model: "plumb_bob"
D: [0.0, 0.0, 0.0, 0.0, 0.0]
K: [526.5478515625, 0.0, 603.1671142578125, 0.0, 526.5478515625, 371.095703125, 0.0, 0.0, 1.0]
R: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
P: [526.5478515625, 0.0, 603.1671142578125, 0.0, 0.0, 526.5478515625, 371.095703125, 0.0, 0.0, 0.0, 1.0, 0.0]
binning_x: 0
binning_y: 0
roi:
x_offset: 0
y_offset: 0
height: 0
width: 0
do_rectify: False
Do you have any idea how to solve this issue?
Thanks a lot in advance
Best
Felix
PS : I also tried an installation from source, but didn't succeeded
Did you figure it out? I have exactly the same situation, ros melodic,
apriltag_ros
build from source. There are visual detections in the image feed as well as in the pose feed but the/tag_detections
topic refuses to produce output. I have another node waiting to callback for this topic and it never gets triggered.rostopic echo /tag_detections
does not do anything. Strange thing is that I can recieve data using plot_juggler, I can see the list of tag_ids there. So I guess there is some problem with the custom message type but I find that very confusing.@rapit Please do not post answers that are not actually answers. I've moved your answer to a question comment.
No, I didn't figured it out. I ended subscribing to the /tf topic and extracting the information I needed from there