pcfitcuboid

Fit cuboid over point cloud

Since R2020b

Syntax

model = pcfitcuboid(ptCloudIn)

model = pcfitcuboid(ptCloudIn,indices)

model = pcfitcuboid(___,Name,Value)

Description

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

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

model = pcfitcuboid(___,Name,Value) specifies options using one or more name-value pair arguments in addition to any of the input argument combinations in previous syntaxes. For example, 'AzimuthRange',[25 75] sets the angular range for the azimuth angles of the function.

Examples

Fit Cuboid Over Point Cloud Data

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')

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')

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

Input Arguments

ptCloudIn — Point cloud

pointCloud object

Point cloud, specified as a pointCloud object.

indices — Indices of selected valid points

vector of positive integers

Indices of selected valid points, specified as a vector of positive integers.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

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.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: 'AzimuthRange',[25 75] sets the angular range for the azimuth angles of the function.

AzimuthRange — Range of azimuth angles

[0 90] (default) | two-element row vector of real values

Range of azimuth angles over which to identify the orientation of the cuboid, specified as the comma-separated pair consisting of 'AzimuthRange' and a two-element row vector of real values in the range [0, 90].

Data Types: single | double

Resolution — Step size of search window

1 (default) | positive scalar

Step size of search window, specified as the comma-separated pair consisting of 'Resolution' and a positive scalar. The specified value must be less than or equal to the distance between the upper and lower bounds of the range of azimuth angles. For example, if the range of azimuth angles is [0, 90], the specified value must be less than or equal to 90.

Note

Decreasing the resolution will increase the computation time and memory footprint.

Data Types: single | double

Output Arguments

model — Cuboid model

cuboidModel object

Cuboid model, returned as a cuboidModel object.

Algorithms

This function uses an L- shape based detection algorithm to fit cuboid to point cloud data. For every point in the point cloud, the function iterates through all possible directions of rectangle and finds the corresponding square errors. The possible directions for the rectangle lie within [0, 90] degrees as the two sides of the rectangle are orthogonal. You can specify the possible rectangle directions by using the AzimuthRange argument. The function then selects the direction that has the least error and fits the rectangle along that direction.

References

[1] Xiao Zhang, Wenda Xu, Chiyu Dong and John M. Dolan, "Efficient L-Shape Fitting for Vehicle Detection Using Laser Scanners", IEEE  Intelligent Vehicles Symposium, June 2018

Extended Capabilities

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

GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Version History

Introduced in R2020b