cylinderModel

R2026b

Object for storing parametric cylinder model

Description

The cylinderModel object stores the parameters of a parametric cylinder model. After you create a cylinderModel object, you can extract cylinder surface points and points within the cylinder using the object functions. Cylinder models are used to store the output of the pcfitcylinder function, which fits a cylinder over a point cloud.

Creation

There are two ways to create a cylinderModel object.

• Create a cylinder model by specifying the cylinder parameters in the cylinderModel object.

• Fit a cylinder model over a point cloud using the pcfitcylinder function.

Description

model = cylinderModel(parameters) constructs a parametric cylinder model from the specified parameters. The parameters argument is a 1-by-7 numeric vector that determines the value of the Parameters property.

Input Arguments

parameters — Cylinder parameters

1-by-7 numeric vector

Cylinder parameters, specified as a 1-by-7 numeric vector. This input specifies the Parameters property. The vector is of the form [x1 y1 z1 x2 y2 z2 r].

• [x1 y1 z1] and [x2 y2 z2] are the 3-D centers of each end-cap surface of the cylinder.

• r is the radius of the cylinder.

Properties

Parameters — Cylinder model parameters

Read-only: 1-by-7 numeric vector

This property is read-only.

Cylinder model parameters, stored as a 1-by-7 numeric vector. The vector is of the form [x1 y1 z1 x2 y2 z2 r].

• [x1 y1 z1] and [x2 y2 z2] are the 3-D centers of each end-cap surface of the cylinder.

• r is the radius of the cylinder.

Center — Center of cylinder

Read-only: 1-by-3 numeric vector

This property is read-only.

Center of the cylinder, stored as a 1-by-3 numeric vector representing the x-, y-, and z-coordinates.

Height — Height of cylinder

Read-only: scalar

This property is read-only.

Height of the cylinder, stored as a scalar.

Radius — Radius of cylinder

Read-only: scalar

This property is read-only.

Radius of the cylinder, stored as a scalar.

Orientation — Orientation of cylinder

Read-only: 1-by-3 vector

This property is read-only.

Orientation of the cylinder, stored as a 1-by-3 vector. The orientation vector points from one center [x1,y1,z1] of the cylinder end-cap to the center [x2,y2,z2] of the other end-cap.

Object Functions

plot	Plot parametric model
findPointsInModel	Find points in or on surface of geometric model
transform	Transform geometric models between coordinate frames

Examples

Detect Cylinder in Point Cloud

Load a MAT file containing a point cloud into the workspace.

load("object3d.mat");

Display the point cloud.

figure
pcshow(ptCloud)
title("Detect a Cylinder in a Point Cloud")

Set the maximum point-to-cylinder distance for cylinder fitting to 5mm.

maxDistance = 0.005;

Specify a region of interest (ROI) to constrain the fitting function.

roi = [0.4 0.6; -inf 0.2; 0.1 inf];
sampleIndices = findPointsInROI(ptCloud,roi);

Set the orientation constraint for the fitting function

referenceVector = [0 0 1];

Detect the cylinder in the specified ROI of the point cloud and extract it.

model = pcfitcylinder(ptCloud,maxDistance,referenceVector, ...
        SampleIndices=sampleIndices);

Plot the model of the detected cylinder.

hold on
plot(model)

Version History

Introduced in R2015b

R2026b: Moved to Point Cloud Toolbox from Computer Vision Toolbox

Starting in R2026b, cylinderModel is available in Point Cloud Toolbox™. In releases R2026a and before, cylinderModel is available in Computer Vision Toolbox™.

R2026b: New transform object function

You can use the new transform object function to transform a cylinderModel between coordinate frames.