cuboidModel

Object for storing parametric cuboid model

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Description

The cuboidModel object stores the parameters of a parametric cuboid model. After you create a cuboidModel object, you can extract cuboid corner points, and points within the cuboid using the object functions. Cuboid models are used to store the output of pcfitcuboid function. It is a shape fitting function which fits a cuboid over a point cloud.

Creation

There are two ways to create a cuboidModel object.

  • Create a cuboid model by specifying the cuboid parameters in the cuboidModel function.

  • Fit a cuboid model over a point cloud using the pcfitcuboid function.

Description

model = cuboidModel(params) constructs a parametric cuboid model from the 1-by-9 input vector, params.

example

model = pcfitcuboid(ptCloudIn) fits a cuboid over the input point cloud data. The pcfitcuboid function stores the properties of the cuboid in a parametric cuboid model object, model.

model = pcfitcuboid(ptCloudIn,indices) fits a cuboid over a selected set of points, indices, in the input point cloud.

example

Properties

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This property is read-only.

Cuboid model parameters, stored as a nine-element row vector of the form [xctr yctr zctr xlen ylen zlen xrot yrot zrot].

  • xctr, yctr, and zctr specify the center of the cuboid.

  • xlen, ylen, and zlen specify the length of the cuboid along the x-, y-, and z-axis, respectively, before rotation has been applied.

  • xrot, yrot, and zrot specify the rotation angles in degrees for the cuboid along the x-, y-, and z-axis, respectively. These angles are clockwise-positive when looking in the forward direction of their corresponding axes.

The figure shows how these values determine the position of a cuboid.

These parameters are specified by the params input argument.

Data Types: single | double

This property is read-only.

Center of the cuboid, stored as a three-element row vector of the form [xctr yctr zctr]. The vector contains the 3-D coordinates of the cuboid center in the x-, y-, and z-axis, respectively.

This property is derived from the Parameters property.

Data Types: single | double

This property is read-only.

Dimensions of the cuboid, stored as a three-element row vector of the form [xlen ylen zlen]. The vector contains the length of the cuboid along the x-, y-, and z-axis, respectively.

This property is derived from the Parameters property.

Data Types: single | double

This property is read-only.

Orientation of the cuboid, stored as a three-element row vector of the form, [xrot yrot zrot], in degrees. The vector contains the rotation of the cuboid along the x-, y-, and z-axis, respectively.

This property is derived from the Parameters property.

If the orientation is in quaternion, convert the quaternion to Euler angles in degrees to create a cuboid model.

  • To convert a quaternion to Euler angles in radians, use the quat2eul (Robotics System Toolbox) function. Set the sequence (Robotics System Toolbox) argument of the quat2eul (Robotics System Toolbox) function to "XYZ".

  • To convert angle units from radians to degrees, use the rad2deg function.

Data Types: single | double

Object Functions

getCornerPointsGet corner points of cuboid model
findPointsInModelFind points enclosed by cuboid model
plotPlot cuboid model

Examples

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Open Live Script

Detect a cuboid in a point cloud using pcfitcuboid function. The function stores the cuboid parameters as a cuboidModel object.

Read point cloud data into the workspace.

ptCloud = pcread('highwayScene.pcd');

Search the point cloud within a specified region of interest (ROI). Create a point cloud of only the detected points.

roi = [-30 30 -20 30 -8 13];
in = findPointsInROI(ptCloud,roi);
ptCloudIn = select(ptCloud,in);

Plot the point cloud of detected points.

   figure
   pcshow(ptCloudIn.Location)
   xlabel('X(m)')
   ylabel('Y(m)')
   zlabel('Z(m)')
   title('Detected Points in ROI')

Find the indices of the points in a specified ROI within the point cloud.

roi = [9.6 13.8 7.9 9.3 -2.5 3];
sampleIndices = findPointsInROI(ptCloudIn,roi);

Fit a cuboid to the selected set of points in the point cloud.

 model = pcfitcuboid(ptCloudIn,sampleIndices);
  figure
  pcshow(ptCloudIn.Location)
  xlabel('X(m)')
  ylabel('Y(m)')
  zlabel('Z(m)')
  title('Detect a Cuboid in a Point Cloud')

Plot the cuboid box in the point cloud.

hold on
plot(model)

Display the internal properties of the cuboidModel object.

model
model = 
  cuboidModel with properties:

     Parameters: [11.4873 8.5997 -1.6138 3.6713 1.3220 1.7576 0 0 0.9999]
         Center: [11.4873 8.5997 -1.6138]
     Dimensions: [3.6713 1.3220 1.7576]
    Orientation: [0 0 0.9999]
Open Live Script

Fit cuboid bounding boxes around clusters in a point cloud.

Load the point cloud data into the workspace. 

data = load('drivingLidarPoints.mat');

Define and crop a region of interest (ROI) from the point cloud. Visualize the selected ROI of the point cloud.

roi = [-40 40 -6 9 -2 1];
in = findPointsInROI(data.ptCloud,roi);
ptCloudIn = select(data.ptCloud,in);
hcluster = figure;
panel = uipanel('Parent',hcluster,'BackgroundColor',[0 0 0]);
ax = axes('Parent',panel,'Color',[0 0 0]); 
pcshow(ptCloudIn,'MarkerSize',30,'Parent',ax)
title('Input Point Cloud')

Figure contains an axes object and an object of type uipanel. The axes object with title Input Point Cloud contains an object of type scatter.

Segment the ground plane. Visualize the segmented ground plane.

maxDistance = 0.3;
referenceVector = [0 0 1];
[~,inliers,outliers] = pcfitplane(ptCloudIn,maxDistance,referenceVector);
ptCloudWithoutGround = select(ptCloudIn,outliers,'OutputSize','full');
hSegment = figure;
panel = uipanel('Parent',hSegment,'BackgroundColor',[0 0 0]);
ax = axes('Parent',panel,'Color',[0 0 0]); 
pcshowpair(ptCloudIn,ptCloudWithoutGround,'Parent',ax)
legend('Ground Region','Non-Ground Region','TextColor', [1 1 1])
title('Segmented Ground Plane')

Figure contains an axes object and an object of type uipanel. The axes object with title Segmented Ground Plane contains 2 objects of type scatter. These objects represent Ground Region, Non-Ground Region.

Segment the non-ground region of the point cloud into clusters. Visualize the segmented point cloud.

distThreshold = 1;
[labels,numClusters] = pcsegdist(ptCloudWithoutGround,distThreshold);
labelColorIndex = labels;
hCuboid = figure;
panel = uipanel('Parent',hCuboid,'BackgroundColor',[0 0 0]);
ax = axes('Parent',panel,'Color',[0 0 0]); 
pcshow(ptCloudIn.Location,labelColorIndex,'Parent',ax)
title('Fitting Bounding Boxes')
hold on

Fit bounding box on each cluster, visualized as orange highlights.

for i = 1:numClusters
    idx = find(labels == i);
    model = pcfitcuboid(ptCloudWithoutGround,idx);
    plot(model)
end

Figure contains an axes object and an object of type uipanel. The axes object with title Fitting Bounding Boxes contains 4 objects of type scatter, patch.

Extended Capabilities

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C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2020b

See Also

Functions

Objects