Revision history [back]

We see this in your rostopic echo output:

Image_raw ;

 $ rostopic echo /camera/color/image_raw
 header: 
   seq: 47205
   stamp: 
     secs: 1615561761
     nsecs: 128132582

and:

$ rostopic echo /semantic_pcl/semantic_image

header: 
   seq: 18
   stamp: 
     secs: 0
     nsecs:         0

Notice the values for the stamp.secs and stamp.nsecs fields.

While ApproximateTime allows some slop (ie: delta-t between messages which it will still consider to be published at the same time), with the values for header.stamp in your messages, there is a difference of about 2021 years between the timestamps of your two message streams.

Is the publisher of /semantic_pcl/semantic_image correctly populating the header of the messages it's publishing?

If it isn't, you need to fix that (either copy the stamp of an incoming message it's processing, or set it to some other meaningful value).