Identifying Boundary Nodes in a Point Cloud

69 次查看（过去 30 天）
Finlay Price
Finlay Price about 24 hours 前
评论： Image Analyst 39 minutes 前
I have 2 point clouds which represent the nodes of 2 3D separate lattices. There is a small gap between the lattices where they don't join together correctly. The boundary face closest to the other body is jagged. I want to identify these bounadry nodes so I can connect them and join my lattices (but the joining part is something I can do in external softwares). Does anyone have any suggestions on how I could go about identifying these boudary nodes? I have tried using the "boundary" function but I am trying with a criteria for identifying the nodes. Any help would be greatly appreciated. I have attached a picture of the nodes for reference.
  4 个评论
显示 2更早的评论
Finlay Price
Finlay Price about 1 hour 前
My apologies, maybe I haven't explained the context of my problem. So each point cloud represents the node points of a lattice. In this case obviously there are 2 separate lattices. Critically, these lattices are not joined to each other and also not of the same type of unit cell, hence their nodes don't align. I am trying to find the closest nodes to each other so I can find joining pairs. I will use these nodes coordinates to create a series of struts through which will attach the lattices. Does that make sense?
Image Analyst
Image Analyst 39 minutes 前
And did the suggestions of pdist2 or knnsearch not work? I've seen other people use them for that situation.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（3 个）

Matt J
Matt J about 23 hours 前
If the regions are supposed to be convex, you can use convhull or convhulln.
  8 个评论
显示 6更早的评论
Finlay Price
Finlay Price about 2 hours 前
Do you have any suggestions on how to identify these points? I know this is a bit of a wild shot haha
Matt J
Matt J about 1 hour 前
You're the one who has made the decision that they belong in the boundary. Once you tell us why, we might have some suggestions.

请先登录，再进行评论。

Walter Roberson
Walter Roberson about 17 hours 前
Your red nodes are sometimes immediately adjacent to your blue nodes. There is no way you will be automatically able to differentiate the nodes -- not unless there is some attached property that can tell them apart (such as color or reflectivity or infrared emission.)
  1 个评论
Finlay Price
Finlay Price about 17 hours 前
I can differentiate between both the red and blue points okay. They are derived from two separate .csv’s which contain their xyz coordinates. It’s more identify the closest ones to each other on those jagged faces :/

请先登录，再进行评论。

Image Analyst
Image Analyst about 12 hours 前
Maybe use either pdist2 or knnsearch to identify blue points that are closest to red points. In other words, pairs that have minimum distance between them.

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by