ar_track_alvar PoseStamped header has no frame
I am using ar_track_alvar to detect AR tags. Even though the message type AlvarMarker
is defined to have a PoseStamped
field:
Header header
uint32 id
uint32 confidence
geometry_msgs/PoseStamped pose
the header frame of pose
is empty:
(Pdb) !ar_marker_message.pose
header:
seq: 0
stamp:
secs: 0
nsecs: 0
frame_id: ''
pose:
position:
x: -0.233206003331
y: 0.0684338694868
z: 1.09863466712
orientation:
x: 0.707971473462
y: 0.699653287423
z: -0.0962229695998
w: -0.00167639034365
This is totally unexpected and confusing. Spent a lot of time debugging a tf issue resulted from this. Why would the frame not be set if the field type is PoseStamped
?
(I know this may not have an answer, but just want to put it here in case someone runs into a similar problem with ar_track_alvar. Also, I am not posting on their github repo's issue as it is not responsive there).