find the plane with two lines

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

find the plane with two lines

qnan1983
Hi Friends

I got two lines with an intersection. Now I want to get the plane composed by these two lines,  do you have any idea for realizing it?

Thank you very much!
Reply | Threaded
Open this post in threaded view
|

Re: find the plane with two lines

james
Administrator
http://mathworld.wolfram.com/Plane.html

You need 3 points to define a plane. Try using the intersection point, and the other end points of each line (or just the points on the line given by RANSAC, if that's how you are currently finding the lines).
Reply | Threaded
Open this post in threaded view
|

Re: find the plane with two lines

qnan1983
Hi James

Thanks for your kindly reply! It's very helpful.
Now I have an another problem.. Yes the two lines are gotten by ransac, but the lines are not very accurate. Even there is no intersection, the two lines are just very closed. I got two points with getMinMax3D on one of these two lines and the third point on the other line as samples.  But after using ransac_plane, the resultant plane is not exactly include these two lines.
Do you have any suggestion for fix this?

Thank you!

Reply | Threaded
Open this post in threaded view
|

Re: find the plane with two lines

james
Administrator
Please supply some code you are working with (only the important bits), and maybe even an image of results if possible.


On Wed, Oct 2, 2013 at 11:28 AM, qnan1983 [via Point Cloud Library (PCL) Users mailing list] <[hidden email]> wrote:
Hi James

Thanks for your kindly reply! It's very helpful.
Now I have an another problem.. Yes the two lines are gotten by ransac, but the lines are not very accurate. Even there is no intersection, the two lines are just very closed. I got two points with getMinMax3D on one of these two lines and the third point on the other line as samples.  But after using ransac_plane, the resultant plane is not exactly include these two lines.
Do you have any suggestion for fix this?

Thank you!




If you reply to this email, your message will be added to the discussion below:
http://www.pcl-users.org/find-the-plane-with-two-lines-tp4029938p4029951.html
To unsubscribe from find the plane with two lines, click here.
NAML

Reply | Threaded
Open this post in threaded view
|

Re: find the plane with two lines

qnan1983
This post was updated on .
CONTENTS DELETED
The author has deleted this message.
Reply | Threaded
Open this post in threaded view
|

Re: find the plane with two lines

airuno2l
Hey guys, if you have two lines, you can take the cross product of them and it will give you the plane's normal. Then you can us the intersection point as the origin. Does that help?
Reply | Threaded
Open this post in threaded view
|

Re: find the plane with two lines

airuno2l
if your lines don't actually intercept, can you project them on to the plane and find it that way?
Reply | Threaded
Open this post in threaded view
|

Re: find the plane with two lines

james
Administrator
I agree. Perhaps you can project the lines. Or if possible, it may be best to search for a plane using RANSAC in the first place without the lines (since you seem to be looking for plane inliers manually anyway).
Reply | Threaded
Open this post in threaded view
|

Re: find the plane with two lines

qnan1983
In reply to this post by airuno2l
Thank you so much guys! I finally found that it is very helpful using the given two lines' unit vector to find the plane's normal. After that I could get a better plane.