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how to save Vlp-16 results

asked 2017-04-04 08:58:49 -0500

eneski gravatar image

Hi everyone I am new in Ros and Lidar.

My project is finding humans in VLP-16 lidar output.

To do that, I have a camera and vlp-16. I need to save images from camera and data from VLP-16. Then I will label corresponding pixels and train them with a ML algorithm.

I am saving images from camera with system time name (30 fps), and I want to save VLP-16 output with x,y,z and intensity. But I could not find how to save VLP-16 output data into a file.

I would be thankful if you could help me about it.

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Hi everyone My project is similar to eneski's, it is necessary to synchronize the data of VLP-16 and image. However,I don't know how to save Synchronous data.I have successfully installed velodyne /ROS-drivers and it can work normally. @eneski :Have you saved the data successfully? Thanks

dongyun2378 gravatar image dongyun2378  ( 2017-05-06 04:13:49 -0500 )edit

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answered 2017-04-10 17:29:10 -0500

joq gravatar image

The usual method for saving ROS messages for later processing is via the rosbag record command.

For velodyne data, it's better to record the /velodyne_packets topic published by the driver. Those messages contain all the data that are subsequently published as a point cloud, but in much more compact form.

For your camera images, you may want to consider saving their compressed format:

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Thaks for your answer,

I have one more question:

Can I get only distance(z) for each frame? Do you know how to do that?

eneski gravatar image eneski  ( 2017-04-12 04:01:12 -0500 )edit

I just want to write all z distance to a file and then I will process them. Because x and y are obviously known, I don't really need them.

eneski gravatar image eneski  ( 2017-04-12 04:03:59 -0500 )edit

I don't quite understand your subsequent question. Please open a new question for that, and try to explain it more clearly.

joq gravatar image joq  ( 2017-04-12 13:23:11 -0500 )edit

my question is special for you, I'm thinking that you made or ( at least know ) this ( ) presentation. I just want to know how to run the in the example. I would be very glad if you could help me.

eneski gravatar image eneski  ( 2017-04-13 10:10:22 -0500 )edit

@piyushk made that for a class lecture and assignment. His students were expected to write and run the subscriber based on the hints provided.

joq gravatar image joq  ( 2017-04-16 09:43:24 -0500 )edit

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Asked: 2017-04-04 08:57:31 -0500

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Last updated: Apr 10 '17