setOccupancy

Set occupancy probability of locations

Syntax

setOccupancy(map,xy,occval)

setOccupancy(map,xy,occval,'local')

setOccupancy(map,ij,occval,'grid')

validPts = setOccupancy(___)

setOccupancy(map,bottomLeft,inputMatrix)

setOccupancy(map,bottomLeft,inputMatrix,'local')

setOccupancy(map,topLeft,inputMatrix,'grid')

Description

This MATLAB^® function assigns the occupancy values to specified locations in an occupancy map.

setOccupancy(map,xy,occval) assigns the occupancy values to each coordinate specified in xy. occval can be a column vector the same size of xy or a scalar, which is applied to all coordinates.

setOccupancy(map,xy,occval,'local') assigns occupancy values, occval, to the input array of local coordinates, xy, as local coordinates.

setOccupancy(map,ij,occval,'grid') assigns occupancy values, occval, to the input array of grid indices, ij, as [rows cols].

validPts = setOccupancy(___) outputs an n-element vector of logical values indicating whether input coordinates are within the map limits.

setOccupancy(map,bottomLeft,inputMatrix) assigns a matrix of occupancy values by specifying the bottom-left corner location in world coordinates.

setOccupancy(map,bottomLeft,inputMatrix,'local') assigns a matrix of occupancy values by specifying the bottom-left corner location in local coordinates.

setOccupancy(map,topLeft,inputMatrix,'grid') assigns a matrix of occupancy values by specifying the top-left cell index in grid indices and the matrix size.

Examples

Create and Modify Occupancy Map

Create an empty map of 10-by-10 meters in size.

map = occupancyMap(10,10,10);

Update the occupancy of specific world locations with new probability values and display the map.

x = [1.2; 2.3; 3.4; 4.5; 5.6];
y = [5.0; 4.0; 3.0; 2.0; 1.0];

pvalues = [0.2; 0.4; 0.6; 0.8; 1];

updateOccupancy(map,[x y],pvalues)
figure
show(map)

Inflate the occupied areas by a radius of 0.5 m. The larger occupancy values overwrite the smaller values.

inflate(map,0.5)
figure
show(map)

Get the grid locations from the world locations.

ij = world2grid(map,[x y]);

Set occupancy values for the grid locations.

setOccupancy(map,ij,ones(5,1),'grid')
figure
show(map)

Input Arguments

map — Map representation

occupancyMap object

Map representation, specified as a occupancyMap object. This object represents the environment of the vehicle. The object contains a matrix grid with values representing the probability of the occupancy of that cell. Values close to 1 represent a high probability that the cell contains an obstacle. Values close to 0 represent a high probability that the cell is not occupied and obstacle free.

xy — World coordinates

n-by-2 matrix

World coordinates, specified as an n-by-2 matrix of [x y] pairs, where n is the number of world coordinates.

Data Types: double

ij — Grid positions

n-by-2 matrix

Grid positions, specified as an n-by-2 matrix of [i j] pairs in [rows cols] format, where n is the number of grid positions.

Data Types: double

occval — Probability occupancy values

scalar | column vector

Probability occupancy values, specified as a scalar or a column vector the same size as either xy or ij. A scalar input is applied to all coordinates in either xy or ij.

Values close to 0 represent a high probability that the cell is not occupied and obstacle free.

inputMatrix — Occupancy values

matrix

Occupancy values, specified as a matrix. Values are given between 0 and 1 inclusively.

bottomLeft — Location of output matrix in world or local

two-element vector | [xCoord yCoord]

Location of bottom left corner of output matrix in world or local coordinates, specified as a two-element vector, [xCoord yCoord]. Location is in world or local coordinates based on syntax.

Data Types: double

topLeft — Location of grid

two-element vector | [iCoord jCoord]

Location of top left corner of grid, specified as a two-element vector, [iCoord jCoord].

Data Types: double

Output Arguments

validPts — Valid map locations

n-by-1 column vector

Valid map locations, returned as an n-by-1 column vector equal in length to xy or ij. Locations inside the map return a value of 1. Locations outside the map limits return a value of 0.

Limitations

Occupancy values have a limited resolution of ±0.001. The values are stored as int16 using a log-odds representation. This data type limits resolution, but saves memory when storing large maps in MATLAB. When calling setOccupancy and then getOccupancy, the value returned might not equal the value you set. For more information, see the log-odds representations section in Occupancy Grids.

Extended Capabilities

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

Version History

Introduced in R2019b