gazebo laser range quantization

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gazebo laser range quantization

Cameron Stone
Hi.

I'm having a problem with the simulated laser range finder in gazebo. The
laser range data gets crappy around about 4 meters away, for objects at a
reasonably acute angle to the sensor (45degrees). After that point, you get
multiple adjacent laser ranges with exactly the same length, and the
values "step" as you move along the line. See the attached image from
playerv. It's almost as if the raygeoms are too "wide", except that that
doesn't seem possible from looking at the ode docs or source code.

This is causing problems in my experiments because there is a bias towards
short ranges in the region described which is warping my estimations of lines
extracted from that data.

Anyone have any ideas?

Cameron.
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Cameron Stone                            <[hidden email]>
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Re: gazebo laser range quantization

Nate Koenig-4
Hello,

In order to improve speed, Gazebo estimates some of the laser range
readings. This can be altered.

Look in worlds/models/sicklms200.model. In the <sensor> section there
are two tags: <rayCount> and <rangeCount>.

<rayCount> Is the number of actual rays Gazebo uses to generate range data.
<rangeCount> Is the number of range values the Gazebo should make
available to player (or libgazebo).

If <rayCount> is less than <rangeCount>, the Gazebo will interpolate
the remaining values. <rayCount> should not be more than <rangeCount>,
otherwise you'll be generating a lot of useless data.

So, if you want more accuracy, set <rayCount> == <rangeCount>

-nate

On Sun, Aug 24, 2008 at 6:28 PM, Cameron Stone <[hidden email]> wrote:

> Hi.
>
> I'm having a problem with the simulated laser range finder in gazebo. The
> laser range data gets crappy around about 4 meters away, for objects at a
> reasonably acute angle to the sensor (45degrees). After that point, you get
> multiple adjacent laser ranges with exactly the same length, and the
> values "step" as you move along the line. See the attached image from
> playerv. It's almost as if the raygeoms are too "wide", except that that
> doesn't seem possible from looking at the ode docs or source code.
>
> This is causing problems in my experiments because there is a bias towards
> short ranges in the region described which is warping my estimations of lines
> extracted from that data.
>
> Anyone have any ideas?
>
> Cameron.
> --
> ===================================================================
>
> What would the world be like if everyone were enlightened? Exactly
> what it is now, except that you would not need to ask that
> question.
>
> Cameron Stone                            <[hidden email]>
> ===================================================================
>
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
>
> _______________________________________________
> Playerstage-gazebo mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/playerstage-gazebo
>
>

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