transform Laser Scan To PointCloud

Question

Dear people,

I want to transform laser to point cloud and then see it in rviz.

I have the following code hokuyo_listener_cu.cpp

I have also a tf_broadcaster.cpp that broadcast a transformation from base_link to base_laser.

when I run hokuyo_listener.cpp I get the error:

what(): Frame id /laser does not exist! Frames (3): Frame /base_laser exists with parent /base_link. Frame /base_link exists with parent NO_PARENT.

Here I have difficulties to really interpret the function

transformLaserScanToPointCloud("base_link", *scan, cloud, tfListener_);

1.-How base_link shall be declare?

2.-and how tfListener_ will get the tf transform?

well, maybe are a very basic questions, but well, I dont get it :) any help will be appreciate it :)

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Originally posted by acp on ROS Answers with karma: 556 on 2011-12-05

Post score: 1

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Original comments

Comment by acp on 2011-12-06:
yes mainly of all them, but I cant figure it out, I need help.

Comment by Eric Perko on 2011-12-05:
Have you gone through all of the beginner tutorials as well as the tf tutorials?

Answer 1

The error that you are getting says that you are trying to perform a transform to/from a frame that does not exist. This is most likely because your laser topic contains a frame_id named "/laser", but your static transform publisher is publishing a transform from "base_laser" instead. You need to make sure that the frame_id on this incoming message is correct.

The string "base_link" in transformLaserScanToPointCloud is the frame_id that you want to transform the cloud into. This is simply declared by you based on what you want to do. There is no default value.

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Originally posted by DimitriProsser with karma: 11163 on 2011-12-06

This answer was ACCEPTED on the original site

Post score: 3

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Original comments

Comment by alfa_80 on 2012-01-24:
@acp: If you try to change "base_link" parameter in transformLaserScanToPointCloud function call with the one with "/" (i mean like this "/base_link"), will there be any difference? is it working as well?

Comment by acp on 2011-12-06:
Hi, In advance thank you for your advise, I made it work now, I can manipulate every single laser ray position and visualize it in ROS.