Overview of Scenario Variant Generation

The Scenario Variant Generator for Automated Driving Toolbox™ support package enables you to automatically generate multiple scenarios by varying the parameters of a seed scenario. Using these generated scenarios, you can perform exhaustive safety assessments of various automated driving applications, such as autonomous emergency braking (AEB), lane keep assist (LKA), and adaptive cruise control (ACC). The support package provides examples to test these applications as per European New Car Assessment Programme (Euro NCAP^®) test protocols.

The process of generating a variant scenario from the seed scenario involves these steps:

1. Read seed scenario and extract its parameters.

2. Modify the parameters of the seed scenario.

3. Generate variant scenario.

To generate variant scenarios, you can create a seed scenario using a drivingScenario object. For more information, see Create Driving Scenario Programmatically. Alternatively, you can generate a seed scenario using real-world vehicle data recorded from various sensors, such as a global positioning system (GPS), camera, and lidar. For more information, see Overview of Scenario Generation from Recorded Sensor Data.

Parameter Extraction

The first step to generate a variant scenario is to extract the parameters from a seed scenario. Use the getScenarioDescriptor function to read a seed scenario and extract its parameters. The function stores the extracted parameters in a ScenarioDescriptor object. You can use this object to modify scenario parameters.

This table shows the different parameters that the getScenarioDescriptor function extracts from the seed scenario.

Extracted Parameters	Description
Scene Parameters	Static parameters related to roads, lanes, and barriers. Examples — Road centers, road width, number of lanes, lane type
Actor Parameters	Dynamic parameters related to actors of the seed scenario. Examples — Speed, yaw, waypoints, dimension
Simulator Parameters	Parameters related to the simulation platform. Examples — Sample time, stop time

If there is a collision between two actors in the seed scenario, you can extract the collision information stored in the ScenarioDescriptor object by using the getCollisionData function. The getCollisionData function extracts these collision information from the seed scenario.

• Simulation time at which collision occurs.

• Coordinates of the collision point.

• Speed of the actors at the time of the collision.

• Side of the actor at which collision occurs.

• Point of collision relative to the collision side of the actors.

Parameter Variation

You can generate a variant of the seed scenario by modifying the actor and collision parameters extracted from the seed scenario.

• Create a variationProperties object to store new values for the actor and collision parameters.

  • Use the varyActorProperties object function to specify the new values for the actor properties such as dimensions, waypoints, speed, and yaw.

  • Use the varyCollisionProperties object function to specify new values for the collision fraction and collision side.

• Use the generateVariants function to modify the actor and collision parameters with the new specified values. The generateVariants function returns a ScenarioDescriptor object that contains the modified parameters.

The generateVariants function automatically computes the required constraints to generate the specified variant scenario. For example, if you want to reduce the speed of an actor, but keep the collision point constant, the generateVariants function can compute the required wait time for the actor to maintain the collision point.

For information about how to perform parameter variations, see the Generate Scenario Variants for Testing AEB Pedestrian Systems example.

Scenario Generation

After performing parameter variations on the ScenarioDescriptor object, generate the variant scenario using the getScenario function. The function constructs the scenario from the parameters stored in the ScenarioDescriptor object and returns the scenario as a drivingScenario object.

You can visualize the generated variants, or export the generated variants to the ASAM OpenSCENARIO^® file format. For more information, see the Generate Scenario Variants for Testing AEB Pedestrian Systems example.