chasePlot

Ego-centric projective perspective plot

Syntax

chasePlot(ac)

chasePlot(ac,Name,Value)

Description

chasePlot(ac) plots a driving scenario from the perspective of actor ac. This plot is called a chase plot and has an ego-centric projective perspective, where the view is positioned immediately behind the actor.

chasePlot(ac,Name,Value) specifies options using one or more name-value pairs. For example, you can display road centers and actor waypoints on the plot.

Examples

Simulate Car Traveling on S-Curve

Simulate a driving scenario with one car traveling on an S-curve. Create and plot the lane boundaries.

Create the driving scenario with one road having an S-curve.

scenario = drivingScenario('StopTime',3);
roadcenters = [-35 20 0; -20 -20 0; 0 0 0; 20 20 0; 35 -20 0];

Create the lanes and add them to the road.

lm = [laneMarking('Solid','Color','w'); ...
    laneMarking('Dashed','Color','y'); ...
    laneMarking('Dashed','Color','y'); ...
    laneMarking('Solid','Color','w')];
ls = lanespec(3,'Marking',lm);
road(scenario,roadcenters,'Lanes',ls);

Add an ego vehicle and specify its trajectory from its waypoints. By default, the car travels at a speed of 30 meters per second.

car = vehicle(scenario, ...
    'ClassID',1, ...
    'Position',[-35 20 0]);
waypoints = [-35 20 0; -20 -20 0; 0 0 0; 20 20 0; 35 -20 0];
smoothTrajectory(car,waypoints);

Plot the scenario and corresponding chase plot.

plot(scenario)

chasePlot(car)

Run the simulation loop.

1. Initialize a bird's-eye plot and create an outline plotter, left-lane and right-lane boundary plotters, and a road boundary plotter.

2. Obtain the road boundaries and rectangular outlines.

3. Obtain the lane boundaries to the left and right of the vehicle.

4. Advance the simulation and update the plotters.

bep = birdsEyePlot('XLim',[-40 40],'YLim',[-30 30]);
olPlotter = outlinePlotter(bep);
lblPlotter = laneBoundaryPlotter(bep,'Color','r','LineStyle','-');
lbrPlotter = laneBoundaryPlotter(bep,'Color','g','LineStyle','-');
rbsEdgePlotter = laneBoundaryPlotter(bep);
legend('off');
while advance(scenario)
    rbs = roadBoundaries(car);
    [position,yaw,length,width,originOffset,color] = targetOutlines(car);
    lb = laneBoundaries(car,'XDistance',0:5:30,'LocationType','Center', ...
        'AllBoundaries',false);
    plotLaneBoundary(rbsEdgePlotter,rbs)
    plotLaneBoundary(lblPlotter,{lb(1).Coordinates})
    plotLaneBoundary(lbrPlotter,{lb(2).Coordinates})
    plotOutline(olPlotter,position,yaw,length,width, ...
        'OriginOffset',originOffset,'Color',color)
end

Show Target Outlines in Driving Scenario Simulation

Create a driving scenario and show how target outlines change as the simulation advances.

Create a driving scenario consisting of two intersecting straight roads. The first road segment is 45 meters long. The second straight road is 32 meters long with jersey barriers along both its edges, and intersects the first road. A car traveling at 12.0 meters per second along the first road approaches a running pedestrian crossing the intersection at 2.0 meters per second.

scenario = drivingScenario('SampleTime',0.1,'StopTime',1);
road1 = road(scenario,[-10 0 0; 45 -20 0]);
road2 = road(scenario,[-10 -10 0; 35 10 0]);
barrier(scenario,road1)
barrier(scenario,road1,'RoadEdge','left')
ped = actor(scenario,'ClassID',4,'Length',0.4,'Width',0.6,'Height',1.7);
car = vehicle(scenario,'ClassID',1);
pedspeed = 2.0;
carspeed = 12.0;
smoothTrajectory(ped,[15 -3 0; 15 3 0],pedspeed);
smoothTrajectory(car,[-10 -10 0; 35 10 0],carspeed);

Create an ego-centric chase plot for the vehicle.

chasePlot(car,'Centerline','on')

Create an empty bird's-eye plot and add an outline plotter and lane boundary plotter. Then, run the simulation. At each simulation step:

• Update the chase plot to display the road boundaries and target outlines.

• Update the bird's-eye plot to display the updated road boundaries and target outlines. The plot perspective is always with respect to the ego vehicle.

bepPlot = birdsEyePlot('XLim',[-50 50],'YLim',[-40 40]);
outlineplotter = outlinePlotter(bepPlot);
laneplotter = laneBoundaryPlotter(bepPlot);
legend('off')

while advance(scenario)
    rb = roadBoundaries(car);
    [position,yaw,length,width,originOffset,color] = targetOutlines(car);
    [bposition,byaw,blength,bwidth,boriginOffset,bcolor,barrierSegments] = targetOutlines(car,'Barriers');
    plotLaneBoundary(laneplotter,rb)
    plotOutline(outlineplotter,position,yaw,length,width, ...
        'OriginOffset',originOffset,'Color',color)
    plotBarrierOutline(outlineplotter,barrierSegments,bposition,byaw,blength,bwidth, ...
        'OriginOffset',boriginOffset,'Color',bcolor)
    pause(0.01)
end

Input Arguments

ac — Actor

Actor object | Vehicle object

Actor belonging to a drivingScenario object, specified as an Actor or Vehicle object. To create these objects, use the actor and vehicle functions, respectively.

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: chasePlot(ac,'Centerline','on','RoadCenters,'on') displays the center line and road centers of each road segment.

Parent — Axes in which to draw plot

Axes object

Axes in which to draw the plot, specified as the comma-separated pair consisting of 'Parent' and an Axes object. If you do not specify Parent, a new figure is created.

Centerline — Display center line of roads

'off' (default) | 'on'

Display the center line of roads, specified as the comma-separated pair consisting of 'Centerline' and 'off' or 'on'. The center line follows the middle of each road segment. Center lines are discontinuous through areas such as intersections or road splits.

RoadCenters — Display road centers

'off' (default) | 'on'

Display road centers, specified as the comma-separated pair consisting of 'RoadCenters' and 'off' or 'on'. The road centers define the roads shown in the plot.

Waypoints — Display actor waypoints

'off' (default) | 'on'

Display actor waypoints, specified as the comma-separated pair consisting of 'Waypoints' and 'off' or 'on'. Waypoints define the trajectory of the actor.

Meshes — Display actor meshes

'off' (default) | 'on'

Display actor meshes instead of cuboids, specified as the comma-separated pair consisting of 'Meshes' and 'off' or 'on'.

ViewHeight — Height of plot viewpoint

1.5 × actor height (default) | positive real scalar

Height of the plot viewpoint, specified as the comma-separated pair consisting of 'ViewHeight' and a positive real scalar. The height is with respect to the bottom of the actor. Units are in meters.

ViewLocation — Location of plot viewpoint

2.5 × actor length (default) | [x, y] real-valued vector

Location of the plot viewpoint, specified as the comma-separated pair consisting of 'ViewLocation' and an [x, y] real-valued vector. The location is with respect to the cuboid center in the coordinate system of the actor. The default location of the viewpoint is behind the cuboid center, [2.5*actor.Length 0]. Units are in meters.

ViewRoll — Roll angle orientation of plot viewpoint

0 (default) | real scalar

Roll angle orientation of the plot viewpoint, specified as the comma-separated pair consisting of 'ViewRoll' and a real scalar. Units are in degrees.

ViewPitch — Pitch angle orientation of plot viewpoint

0 (default) | real scalar

Pitch angle orientation of the plot viewpoint, specified as the comma-separated pair consisting of 'ViewPitch' and a real scalar. Units are in degrees.

ViewYaw — Yaw angle orientation of plot viewpoint

0 (default) | real scalar

Yaw angle orientation of the plot viewpoint, specified as the comma-separated pair consisting of 'ViewYaw' and a real scalar. Units are in degrees.

Version History

Introduced in R2017a