findPointsInCylinder

Find points within a cylindrical region in a point cloud

Since R2023a

Syntax

indices = findPointsInCylinder(ptCloud,radius)

indices = findPointsInCylinder(___,Name=Value)

Description

indices = findPointsInCylinder(ptCloud,radius) finds the points within a cylindrical neighborhood of the specified radius in a point cloud, ptCloud.

indices = findPointsInCylinder(___,Name=Value) specifies options using one or more name-value arguments in addition to the previous syntax. For example, Height=10, sets the height of the cylinder to 10.

Examples

Find Points in Hollow Cylinder

Load a point cloud from a saved MAT file.

load("drivingLidarPoints.mat","ptCloud")

Specify a hollow cylindrical neighborhood with an inner radius of 2 meters and an outer radius of 15 meters, and find the points in the point cloud within the neighborhood.

minRadius = 2;
maxRadius = 15;

indices = findPointsInCylinder(ptCloud,[minRadius maxRadius]);

Select the cylindrical neighborhood in the point cloud, preserving the organized format.

ptCloudCylinder = select(ptCloud,indices,OutputSize="full");

Visualize the selected points.

figure
pcshow(ptCloudCylinder)

Apply Solid Cylindrical Filter Centered Around Point of Interest

Load a point cloud from a saved MAT file.

load("object3d.mat","ptCloud")
maxRadius = 0.1;
cylinderHeight = 0.5;

Offset the center of the cylinder 0.6 units in the X-direction and 0.2 units in the Z-direction. Then, find and select the points of the point cloud within the cylinder.

shiftedCenter = [0.6 0 0.2];
indices = findPointsInCylinder(ptCloud,maxRadius,Height=cylinderHeight,Center=shiftedCenter,VerticalAxis="Z");
ptCloudCylinder = select(ptCloud,indices);

Visualize the selected points.

figure
pcshow(ptCloudCylinder)

Input Arguments

ptCloud — Point cloud

pointCloud object

Point cloud, specified as a pointCloud object.

radius — Cylinder radius

scalar | 2-element vector

Cylinder radius, specified as a scalar or a 2-element vector of the form [minRadius maxRadius] that specifies the inner and outer radii of the cylindrical neighborhood. The function finds the neighbors within the specified radius around a query point in the input point cloud.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: Height=10 sets the height of the cylinder to 10.

Height — Height of cylinder

Inf (default) | positive scalar

Height of cylinder, specified as a positive scalar.

Center — Center of cylinder

[0 0 0] (default) | 3-element vector

Center of the cylinder, specified as a 3-element vector of the form [x y z] in Cartesian coordinates. The center point is halfway between the top and bottom of the cylinder, and the axis of the cylinder passes through it.

VerticalAxis — Vertical axis of cylinder

"Z" (default) | "X" | "Y"

Vertical axis of the cylinder, specified as "X", "Y", or "Z".

Output Arguments

indices — Logical indices of points within cylindrical neighborhood

column vector | matrix

Logical indices of the points within a cylindrical neighborhood, returned as a column vector for unorganized point clouds or a matrix for organized point clouds. For organized point clouds. indices is the same size as the input point cloud, and each element with a value of 1 (true) indicates that the corresponding index of the input point cloud references a point inside the specified cylindrical neighborhood.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

Version History

Introduced in R2023a