pcmaploam

Create map of LOAM feature points for map building

Since R2022b

Description

The pcmaploam object creates a map of lidar odometry and mapping (LOAM) feature points. LOAM feature points represent edge points and surface points that are detected using the LOAM algorithm. Use this object for incremental map building workflows. Use the findPose function to find the optimized absolute pose that aligns the points to the map, and use the addPoints function to add points to the map.

Creation

Syntax

loamMap = pcmaploam(voxelSize)

loamMap = pcmaploam(voxelSize,mapSize)

Description

loamMap = pcmaploam(voxelSize) returns an empty LOAM map with the voxel size set by the voxelSize argument.

loamMap = pcmaploam(voxelSize,mapSize) also specifies the size of the map along each axis (x, y, and z). By default, using the addPoints function to add points outside the existing LOAM map expands the map. If you specify the mapSize argument, the pcmaploam object instead discards points outside the specified boundaries. The mapSize argument sets the MapSize property.

Use this syntax to improve the speed of the findPose and addPoints functions when mapping large areas.

Properties

Points — Points in LOAM map

M-by-3 matrix

Points in the LOAM map, specified as an M-by-3 matrix, where M is the number of points. Each row specifies the [x y z] coordinates of a point.

VoxelSize — Voxel size to use for downsampling map points

positive scalar

Voxel size to use for downsampling map points, specified as a positive scalar.

MapSize — Size of LOAM map

[[Inf Inf Inf] | three-element vector

Size of the LOAM map, specified as a three-element vector of the form [dx dy dz].

XLimits — Range of LOAM map along x-axis

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

Range of the LOAM map along the x-axis, specified as a two-element vector of the form [xmin xmax].

YLimits — Range of LOAM map along y-axis

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

Range of the LOAM map along the y-axis, specified as a two-element vector of the form [ymin ymax].

ZLimits — Range of LOAM map along z-axis

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

Range of LOAM map along the z-axis, specified as a two-element vector of the form [zmin zmax].

Object Functions

addPoints	Add LOAM points to map
findPose	Find absolute pose of points in map
show	Visualize LOAM map

Examples

Create LOAM Map

Create a map to store LOAM feature points.

voxelSize = 0.1;
loamMap = pcmaploam(voxelSize);

Create a velodyneFileReader object to read point cloud data from a PCAP file.

veloReader = velodyneFileReader("lidarData_ConstructionRoad.pcap","HDL32E");

Read the first point cloud from the file into the workspace.

ptCloud1 = readFrame(veloReader,1);

Detect LOAM feature points in the point cloud.

points1 = detectLOAMFeatures(ptCloud1);

Downsample the less planar surface points to improve registration speed.

gridStep = 1;
points1 = downsampleLessPlanar(points1,gridStep);

Add the LOAM points of the first point cloud to the map.

absPose = rigidtform3d;
addPoints(loamMap,points1,absPose)

Read the fifth point cloud, and detect the LOAM feature points in it.

ptCloud2 = readFrame(veloReader,5);
points2 = detectLOAMFeatures(ptCloud2);

Downsample the less planar surface points.

points2 = downsampleLessPlanar(points2,gridStep);

Get a relative pose estimate by using the pcregisterloam function.

relPose = pcregisterloam(points2,points1);

Find the absolute pose of the points from the fifth point cloud in the map.

absPose = findPose(loamMap,points2,relPose);

Add the LOAM points from the fifth point cloud to the map.

addPoints(loamMap,points2,absPose)

Visualize the map.

show(loamMap,MarkerSize=20)

Extended Capabilities

C/C++ Code Generation

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

Usage notes and limitations:

• The show function of this object does not support code generation.

• When you add points by using the addPoints object function, the Location property of all points in the points input must have the same datatype.

GPU Code Generation

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

Usage notes and limitations:

• The show function of this object does not support code generation.

• When you add points by using the addPoints object function, the Location property of all points in the points input must have the same datatype.

Version History

Introduced in R2022b