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Converting /scan data for Lidar that is not centered on Robot

noetic

asked 2022-08-22 06:05:28 -0600

pitosalas
628 ●116 ●149 ●169

My Lidar is not centered over the Robot/ Generally for SLAM and AMCL I think that's ok because if you have the tfs set up correctly then Slam and AMCL will take it into account.

However, I am using /scan messages which give me, let’s say, 360 numbers, corresponding to the distance of an obstacle from the lidar. To know the distance from the robot, I need to do a little converting, involving some trigonometry, using information that I get from tf.

This must be a solved problem. Can someone give me a pointer perhaps?

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I suggest subscribing to the /scan topic and then converting those polar coordinates to Cartesian coordinates. Once you have Cartesian coordinates as XYZ values, you can transform those points simply by one matrix multiplication.

ravijoshi ( 2022-08-23 02:44:27 -0600 )edit

Yeah that sounds like the way to go. Thanks. If you make this into an answer I will mark it good!!

pitosalas ( 2022-08-23 14:07:04 -0600 )edit

@pitosalas Done

ravijoshi ( 2022-08-23 23:08:44 -0600 )edit

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answered 2022-08-23 23:08:16 -0600

1744 ●66 ●163 ●103 https://ravijoshi.xyz

I suggest subscribing to the /scan topic and then converting those polar coordinates to Cartesian coordinates.

Once you have Cartesian coordinates as XYZ values, you can transform these points simply by one matrix multiplication.

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Asked: 2022-08-22 06:05:28 -0600

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Last updated: Aug 23 '22

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