The topic /tf doesn't publish frame ID "camera" pose.

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I'm using roscpp , and I tried : listener.waitForTransform("camera", "my_bundle", ros::Time(0), ros::Duration(3.0)); listener.lookupTransform("camera", "my_bundle", ros::Time(0), transform);

but terminal always call back :

"camera" passed to lookupTransform argument target_frame does not exist.

However, the "camera" is acturly exist.

In the rviz image you posted, frame "camera" has no parent frame. This implies that it is not connected to the rest of the transform tree.

As you said, "camera" has no parent frame ID, but my TF tree only has "camera", "tag_ID" and "my_bundle", and "camera" is the parent of "tag_ID" and "my_bundle".

This means that the "camera" cannot use lookupTransform?

I use sendtransform to know the "my_bundle" and the "camera" TF, but as the figure you saw, the published TF doesn't mean the posture of "camera" when the fixed frame is "my_bundle".

So how do I know the posture of the "camera" when the fixed frame is "my_bundle"?

Your original question was how to get the pose of "camera" frame. It doesn't really make sense to ask for the pose (more accurately: transform) of the frame at the top of the TF tree.

Regarding your lookupTransform() call, it looks ok to me, assuming the necessary data has actually been published on /tf or /tf_static since you started the node. You need to be careful of what you see in rviz, which will cache previously-published transforms that are no longer being published; in that situation the lookupTransform() call will fail. You can clear the rviz cache by clicking the "Reset" button in the lower left corner of rviz.

"Your original question was how to get the pose of "camera" frame. It doesn't really make sense to ask for the pose (more accurately: transform) of the frame at the top of the TF tree."

I didn't phrase this well. Please ignore these two sentences.