clothoidLaneBoundary

Clothoid-shaped lane boundary model

Description

A clothoidLaneBoundary object contains information about a clothoid-shaped lane boundary model. A clothoid is a type of curve whose rate of change of curvature varies linearly with distance.

Creation

Syntax

bdry = clothoidLaneBoundary

bdry = clothoidLaneBoundary(Name,Value)

Description

bdry = clothoidLaneBoundary creates a clothoid lane boundary model, bdry with default property values.

bdry = clothoidLaneBoundary(Name,Value) sets properties using one or more name-value pairs. For example, clothoidLaneBoundary('BoundaryType','Solid') creates a clothoid lane boundary model with solid lane boundaries. Enclose each property name in quotes.

Properties

Curvature — Lane boundary curvature

0 (default) | real scalar

Lane boundary curvature, specified as a real scalar. This property represents the rate of change of lane boundary direction with respect to distance. Units are in degrees per meter.

Example: -1.0

Data Types: single | double

CurvatureDerivative — Derivative of lane boundary curvature

0 (default) | real scalar

Derivative of lane boundary curvature, specified as a real scalar. This property represents the rate of change of lane curvature with respect to distance. Units are in degrees per meter squared.

Example: -0.01

Data Types: single | double

CurveLength — Length of lane boundary along road

0 (default) | nonnegative real scalar

Length of the lane boundary along the road, specified as a nonnegative real scalar. Units are in meters.

Example: 25

Data Types: single | double

HeadingAngle — Initial lane boundary heading

0 (default) | real scalar

Initial lane boundary heading, specified as a real scalar. The heading angle of the lane boundary is relative to the heading of the ego vehicle. Units are in degrees.

Example: 10

Data Types: single | double

LateralOffset — Lateral offset of ego vehicle position from lane boundary

0 (default) | real scalar

Lateral offset of the ego vehicle position from the lane boundary, specified as a real scalar. An offset to a lane boundary to the left of the ego vehicle is positive. An offset to the right of the ego vehicle is negative. Units are in meters. In this image, the ego vehicle is offset 1.5 meters from the left lane and 2.1 meters from the right lane.

Example: -1.2

Data Types: single | double

BoundaryType — Type of lane boundary marking

'Unmarked' (default) | 'Solid' | 'Dashed' | 'DoubleSolid' | 'DoubleDashed' | 'SolidDashed' | 'DashedSolid'

Type of lane boundary marking, specified as one of these values.

'Unmarked'	'Solid'	'Dashed'	'DoubleSolid'	'DoubleDashed'	'SolidDashed'	'DashedSolid'
No lane marking	Solid line	Dashed line	Two solid lines	Two dashed lines	Solid line on left, dashed line on right	Dashed line on left, solid line on right

Strength — Visibility of lane boundary marking

1 (default) | real scalar in the range [0, 1]

Visibility of lane marking, specified as a real scalar in the range [0, 1]. A value of 0 corresponds to a marking that is not visible. A value of 1 corresponds to a marking that is completely visible. For a double lane marking, the same strength is used for both lines.

Example: 0.9

Data Types: single | double

XExtent — Extent of lane boundary marking along X-axis

[0 Inf] (default) | real-valued vector of the form [X_min X_max]

Extent of the lane boundary marking along the X-axis, specified as a real-valued vector of the form [X_min X_max]. Units are in meters. The X-axis runs vertically and is positive in the forward direction of the ego vehicle.

Example: [0 100]

Data Types: single | double

Width — Width of lane boundary marking

0 (default) | nonnegative real scalar

Width of lane boundary marking, specified as a nonnegative real scalar. For a double lane marking, this value applies to the width of each lane marking and to the distance between those markings. Units are in meters.

Example: 0.15

Data Types: single | double

Object Functions

computeBoundaryModel

Compute lane boundary points from clothoid lane boundary model

Examples

Create Clothoid Lane Boundaries

Create clothoid curves to represent left and right lane boundaries. Then, plot the curves.

Create the left boundary.

lb = clothoidLaneBoundary('BoundaryType','Solid', ...
'Strength',1,'Width',0.2,'CurveLength',40, ...
'Curvature',-0.8,'LateralOffset',2,'HeadingAngle',10);

Create the right boundary with almost identical properties.

rb = lb;
rb.LateralOffset = -2;

Create a bird's-eye plot. Then, create the lane boundary plotters and plot the boundaries.

bep = birdsEyePlot('XLimits',[0 50],'YLimits',[-10 10]);
lbPlotter = laneBoundaryPlotter(bep,'DisplayName','Left-lane boundary','Color','r');
rbPlotter = laneBoundaryPlotter(bep,'DisplayName','Right-lane boundary','Color','g');
plotLaneBoundary(lbPlotter,lb)
plotLaneBoundary(rbPlotter,rb);

grid
hold on

Plot the coordinates of selected points along the boundaries.

x = 0:5:50;
yl = computeBoundaryModel(lb,x);
yr = computeBoundaryModel(rb,x);
plot(x,yl,'ro')
plot(x,yr,'go')
hold off

Version History

Introduced in R2018a