show

Display 3-D occupancy map

Syntax

axes = show(map3D)

show(map3D,Name=Value)

Description

axes = show(map3D) displays the occupancy map, map3D, in the current axes, with the axes labels representing the world coordinates.

The function displays the 3-D environment using 3-D voxels for areas with occupancy values greater than the OccupiedThreshold property value specified in map3D. The color of the 3-D plot is strictly height-based.

show(map3D,Name=Value) specifies options using one or more name-value arguments.

Examples

Get Ray Intersection Points on 3-D Occupancy Map

Import a 3-D occupancy map.

map3D = importOccupancyMap3D("citymap.ot")

map3D = 
  occupancyMap3D with properties:

    ProbabilitySaturation: [1.0000e-03 0.9990]
               Resolution: 1
        OccupiedThreshold: 0.6500
            FreeThreshold: 0.2000

Inflate the occupied areas by a radius of 1 m. Display the map.

inflate(map3D,1)
show(map3D)

Find the intersection points of rays and occupied map cells.

numRays = 10;
angles = linspace(-pi/2,pi/2,numRays);
directions = [cos(angles); sin(angles); zeros(1,numRays)]';
sensorPose = [55 40 1 1 0 0 0];
maxrange = 15;
[intersectionPts,isOccupied] = rayIntersection(map3D,sensorPose,directions,maxrange)

intersectionPts = 10×3

   55.0000   32.0000    1.0000
   57.9118   32.0000    1.0000
   61.7128   32.0000    1.0000
   67.9904   32.5000    1.0000
   69.0000   37.5314    1.0000
   69.0000   42.4686    1.0000
   67.9904   47.5000    1.0000
   64.6418   51.4907    1.0000
   58.2757   49.0000    1.0000
   55.0000   49.0000    1.0000

isOccupied = 10×1

     1
     1
     1
    -1
     1
     1
    -1
    -1
     1
     1

Plot the intersection points and plot rays from the pose to the intersection points.

hold on
plotTransforms(sensorPose(1:3),sensorPose(4:end),...
               'FrameSize',5,'MeshFilePath','groundvehicle.stl') % Vehicle sensor pose
for i = 1:numRays
    plot3([sensorPose(1),intersectionPts(i,1)],...
          [sensorPose(2),intersectionPts(i,2)],...
          [sensorPose(3),intersectionPts(i,3)],'-b') % Plot rays
    if isOccupied(i) == 1
        plot3(intersectionPts(i,1),intersectionPts(i,2),intersectionPts(i,3),'*r') % Intersection points
    end
end

Visualize 3-D Occupancy Maps with Varying Search Depths

Create a 3-D occupancy map and set 25 random coordinates in the occupancy map as occupied.

map = occupancyMap3D;
rng(0);
for i = 1:25
    pt = (rand(1,3)-.5)*20;
    map.setOccupancy(pt,1);
end

Visualize the voxels with the default search depth value, 16.

show(map)
axis equal
grid on

Decrease the search depth in increments of 1 and notice that the resolution drops as you decrease the search depth.

show(map,SearchDepth=15)
axis equal
grid on

show(map,SearchDepth=14)
axis equal
grid on

show(map,SearchDepth=13)
axis equal
grid on

Input Arguments

map3D — 3-D occupancy map

occupancyMap3D object

3-D occupancy map, specified as an occupancyMap3D object.

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: show(map,SearchDepth=14)

Parent — Axes used to plot the map

Axes object | UIAxes object

Axes used to plot the map, specified as either an Axes or UIAxes object. See axes or uiaxes.

SearchDepth — Voxel search depth

16 (default) | integer in the range [0,16]

Voxel search depth, specified as an integer in the range [0,16], which determines the level-of-detail at which the map is displayed. The maximum depth is 16, corresponding to voxels whose edge length is equal to 1/map.Resolution. Each level above the maximum depth doubles this minimum voxel size.

Output Arguments

axes — Axes handle for map

Axes object | UIAxes object

Axes handle for map, returned as either an Axes or UIAxesobject. See axes or uiaxes.

Version History

Introduced in R2019b