Distance measure in radiusSearch

classic Classic list List threaded Threaded
4 messages Options
Reply | Threaded
Open this post in threaded view
|

Distance measure in radiusSearch

vernal
Hi all,

what kind of distance is the result of radiusSearch? I obtain values different from the Euclidean distance and can't figure out what metric is used. It also seems not to be the Manhattan metric.

Query point: X:101 Y:17 Z:11

Result points:
        X:101.07813     Y:17.367188     Z:11.811523
        idx:49  dist:0.79950047 EuclDist: 0.8941479

        X:112.21875     Y:10.789063     Z:9.1005859
        idx:296 dist:168.04387  EuclDist: 12.963174

        X:87.4375       Y:11.359375     Z:8.7485352
        idx:290 dist:220.82715  EuclDist: 14.860254

        X:92.992188     Y:28.71875      Z:15.474121
        idx:148 dist:221.47192  EuclDist: 14.881933

Cheers
vernal
Reply | Threaded
Open this post in threaded view
|

Re: Distance measure in radiusSearch

Zoltan-Csaba Marton
Hi Vernal,

the distances are squared Euclidean distances. There was some talk of
documenting this better, but maybe we did it only for the old ANN
wrapper? I'll check.

Cheers,
Zoltan

On Tue, 2011-02-08 at 03:39 -0800, vernal wrote:

> Hi all,
>
> what kind of distance is the result of radiusSearch? I obtain values
> different from the Euclidean distance and can't figure out what metric is
> used. It also seems not to be the Manhattan metric.
>
> Query point: X:101 Y:17 Z:11
>
> Result points:
>         X:101.07813     Y:17.367188     Z:11.811523
>         idx:49  dist:0.79950047 EuclDist: 0.8941479
>
>         X:112.21875     Y:10.789063     Z:9.1005859
>         idx:296 dist:168.04387  EuclDist: 12.963174
>
>         X:87.4375       Y:11.359375     Z:8.7485352
>         idx:290 dist:220.82715  EuclDist: 14.860254
>
>         X:92.992188     Y:28.71875      Z:15.474121
>         idx:148 dist:221.47192  EuclDist: 14.881933
>
> Cheers
> vernal


_______________________________________________
[hidden email] / http://pointclouds.org
https://code.ros.org/mailman/listinfo/pcl-users
Reply | Threaded
Open this post in threaded view
|

Re: Distance measure in radiusSearch

vernal
Thank you! I definitely should have seen that from the numbers... *sigh*
Reply | Threaded
Open this post in threaded view
|

Re: Distance measure in radiusSearch

Zoltan-Csaba Marton
No problem! I now added the documentation to the KdTree superclass as
well, so people can find it even if they look there instead of
KdTreeFLANN. I also renamed the parameter there to k_sqr_distances.

On Tue, 2011-02-08 at 06:54 -0800, vernal wrote:
> Thank you! I definitely should have seen that from the numbers... *sigh*


_______________________________________________
[hidden email] / http://pointclouds.org
https://code.ros.org/mailman/listinfo/pcl-users