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Create collision map from Kinect with nodelet

asked 2012-07-19 22:00:27 -0500

jep31 gravatar image

updated 2016-10-24 09:03:30 -0500

ngrennan gravatar image


I use a camera Kinect for create a collision map but currently it's too slow and use 100% CPU. So I want use nodelets to avoid useless copies of pointCloud and speed up the process. I understand how I should use nodelet with openni_launch because I have a good explaining here: Get start with ROS Nodelet

My question is How create a collision map with nodelet ? Currently I use octomap_server to construct the map but it's not a nodelet.

It's necessary to modify the package ocotomap_server to porting nodes to nodelets ?

Or it's possible to run this node as nodelets with a change in the launch file ?

Or existing other package to construct collision map with nodelets ?



I have tried with two computer: (With system Monitor)

The first work with two CPU at 100%: Ubuntu 10.04 / Ros Electric / Memory 3.9 GiB / Two processor Intel Core(TM)2 6600 @ 2.40GHz

The second work well, it have only a CPU at 100%, it have 8 CPU: Unbuntu 12.04 / Ros Electric / Memory 15.7 GiB / Height processor Intel(R)Xeon(R) W3565 @ 3.20 GHz

EDIT 2: New subject on how create this node: Build a octomap_server nodelet

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You have no tags on your question, it is unlikely to be found by people who know about these things

Felix Endres gravatar image Felix Endres  ( 2012-07-19 23:05:00 -0500 )edit

Yes it's true. Now that's good. thank you

jep31 gravatar image jep31  ( 2012-07-22 02:24:04 -0500 )edit

What are the specs (CPU type, speed, RAM, etc) of the computer you are trying to create the collision map on?

Eric Perko gravatar image Eric Perko  ( 2012-07-22 19:34:32 -0500 )edit

I have did a EDIT. A other question, We will soon use Fuerte. Is there a change between Electric and Fuerte with octomap_server ? It's for know if my work on electric can be used on Fuerte without change.

jep31 gravatar image jep31  ( 2012-07-22 20:23:05 -0500 )edit

New (unrelated) questions tend to get lost in comments, but nevertheless: see the Changelog:

AHornung gravatar image AHornung  ( 2012-07-22 22:03:48 -0500 )edit

In general, the Fuerte version got a few new features and will be worked on, while electric will stay as it is. There should not be a change for you, I think.

AHornung gravatar image AHornung  ( 2012-07-22 22:04:47 -0500 )edit

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answered 2012-07-20 01:44:43 -0500

AHornung gravatar image

Yes, you would need to write your own Nodelet using octomap_server. That should be easily possible, since you can just internally use the OctomapServer class (C++ API instead of ROS node API).

However, I would guess that most of the CPU load comes from expensive map updates and ray casting, instead of pointcloud serialization/deserialization. A Nodelet would not speed up much in that case, but it might be worth a try.

Note that octomap_server outputs detailed timing on the debug log level, so you can estimate the time it takes to just insert the pointclouds into the map.

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Ok I will try to write my own nodelet with the OctomapServer class. Now I work with a computer with 8 CPU more efficient (Before 2 CPU) but we want improve the speed a maximum. I think the copy of the pointCloud between node is expensive also. Very useful a tool to estimate time, thx

jep31 gravatar image jep31  ( 2012-07-22 02:15:41 -0500 )edit

There is no parallelization in octomap or octomap_server, so for that case only the specs of a single CPU will count.

AHornung gravatar image AHornung  ( 2012-07-22 22:06:06 -0500 )edit

answered 2012-07-20 06:33:54 -0500

Only loosely related, but you could set the kinect to QVGA (e.g. using dynamic_reconfigure). This will decrease the cloud resolution very efficiently.

You can also use a voxel grid filter or filter out far points (passthrough filter).

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Yes I also work on the quality of point cloud. The resolution is the more efficiently to reduce the time. I want also select a region of point cloud to limit the size. I don't know the voxel grid filter out far points. Is used for that? Have you more detail of this ? It's in openni launch ?

jep31 gravatar image jep31  ( 2012-07-22 02:22:27 -0500 )edit

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Asked: 2012-07-19 22:00:27 -0500

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Last updated: Aug 19 '12