# Lidar Point Cloud Generator

**Libraries:**

Automated Driving Toolbox /
Driving Scenario and Sensor Modeling

## Description

The Lidar Point Cloud Generator block generates a point cloud from lidar measurements taken by a lidar sensor mounted on an ego vehicle.

The block derives the point cloud from simulated roads and actor poses in a driving scenario and generates the point cloud at intervals equal to the sensor update interval. By default, detections are referenced to the coordinate system of the ego vehicle. The block can simulate added noise at a specified range accuracy by using a statistical model. The block also provides parameters to exclude the ego vehicle and roads from the generated point cloud.

The lidar generates point cloud data based on the mesh representations of the roads and
actors in the scenario. A *mesh* is a 3-D geometry of an object that is
composed of faces and vertices.

When building scenarios and sensor models using the **Driving Scenario
Designer** app, the lidar sensors exported to Simulink^{®} are output as Lidar Point Cloud Generator blocks.

## Examples

## Limitations

C/C++ code generation is not supported.

For Each subsystems are not supported.

Rapid acceleration mode is not supported.

Use of the Detection Concatenation block with this block is not supported. You cannot concatenate point cloud data with detections from other sensors.

If a model does not contain a Scenario Reader block, then this block does not include roads in the generated point cloud.

Point cloud data is not generated for lane markings.

## Ports

### Input

**Actors** — Scenario actor poses

Simulink bus containing MATLAB^{®} structure

Scenario actor poses in ego vehicle coordinates, specified as a Simulink bus containing a MATLAB structure.

The structure must contain these fields.

Field | Description | Type |
---|---|---|

`NumActors` | Number of actors | Nonnegative integer |

`Time` | Current simulation time | Real-valued scalar |

`Actors` | Actor poses | `NumActors` -length array of actor pose structures |

Each actor pose structure in `Actors`

must have these
fields.

Field | Description |
---|---|

`ActorID` | Scenario-defined actor identifier, specified as a positive integer. |

`Position` | Position of actor, specified as a real-valued
vector of the form [ |

`Velocity` | Velocity ( |

`Roll` | Roll angle of actor, specified as a real-valued scalar. Units are in degrees. |

`Pitch` | Pitch angle of actor, specified as a real-valued scalar. Units are in degrees. |

`Yaw` | Yaw angle of actor, specified as a real-valued scalar. Units are in degrees. |

`AngularVelocity` | Angular velocity ( |

**Ego Vehicle** — Ego vehicle pose

Simulink bus containing MATLAB structure

Ego vehicle pose, specified as a Simulink bus containing a MATLAB structure.

The structure must have these fields.

Field | Description |
---|---|

`ActorID` | Scenario-defined actor identifier, specified as a positive integer. |

`Position` | Position of actor, specified as a real-valued
vector of the form [ |

`Velocity` | Velocity ( |

`Roll` | Roll angle of actor, specified as a real-valued scalar. Units are in degrees. |

`Pitch` | Pitch angle of actor, specified as a real-valued scalar. Units are in degrees. |

`Yaw` | Yaw angle of actor, specified as a real-valued scalar. Units are in degrees. |

`AngularVelocity` | Angular velocity ( |

You can output the ego vehicle pose from a Scenario
Reader block. In the Scenario Reader block used in your
model, select the **Output ego vehicle pose** parameter.

### Output

**Point Cloud** — Point cloud data

*m*-by-*n*-by-3 array of positive real-valued
[*x*, *y*, *z*] points

Point cloud data, returned as an *m*-by-*n*-by 3
array of positive real-valued [*x*, *y*,
*z*] points. *m* is the number of elevation
(vertical) channels in the point cloud. *n* is the number of
azimuthal (horizontal) channels in the point cloud. *m* and
*n* define the number of points in the point cloud, as shown in
this equation:

$$m\times n=\frac{{V}_{FOV}}{{V}_{RES}}\times \frac{{H}_{FOV}}{{H}_{RES}}$$

*V*_{FOV}is the vertical field of view of the lidar, in degrees, as specified by the**Elevation limits of lidar (deg)**parameter.*V*_{RES}is the vertical angular resolution of the lidar, in degrees, as specified by the**Elevation resolution of lidar (deg)**parameter.*H*_{FOV}is the horizontal field of view of the lidar, in degrees, as specified by the**Azimuthal limits of lidar (deg)**parameter.*H*_{RES}is the horizontal angular resolution of the lidar, in degrees, as specified by the**Azimuthal resolution of lidar (deg)**parameter.

Each *m*-by-*n* entry in the array specifies the
*x*-, *y*-, and *z*-coordinates
of a detected point in the ego vehicle coordinate system. If the lidar does not detect
a point at a given coordinate, then *x*, *y*, and
*z* are returned as `NaN`

.

By default, the Lidar Point Cloud Generator block includes road
data in the generated point cloud. The block obtains the road data in world
coordinates from a Scenario
Reader block that is in the same model as the Lidar Point Cloud
Generator block. The Lidar Point Cloud Generator block
computes the road mesh in ego vehicle coordinates based on the road data and the ego
vehicle pose at the **Ego Vehicle** input port. The **Maximum
detection range (m)** parameter of the Lidar Point Cloud
Generator block determines the extent of the road mesh. To exclude road data
from the point cloud, clear the **Include roads in generated point
cloud** parameter.

## Parameters

### Parameters

**Sensor Identification**

**Unique identifier of sensor** — Unique sensor identifier

`1`

(default) | positive integer

Unique sensor identifier, specified as a positive integer. The sensor identifier
distinguishes detections that come from different sensors in a multisensor system. If
a model contains multiple sensor blocks that have the same sensor identifier, the **Bird's-Eye
Scope** displays an error.

**Required interval between sensor updates (s)** — Required time interval between sensor updates

`0.1`

(default) | positive scalar

Required time interval between sensor updates, specified as a positive scalar. The
value of this parameter must be an integer multiple of the **Actors**
input port data interval. Updates requested from the sensor between update intervals
contain no detections. Units are in seconds.

**Sensor Extrinsics**

**Sensor's (x,y) position (m)** — Location of center of lidar sensor

`[1.5 0]`

(default) | real-valued 1-by-2 vector

Location of the center of the lidar sensor, specified as a real-valued 1-by-2
vector. The **Sensor's (x,y) position (m)** and **Sensor's
height (m)** parameters define the coordinates of the lidar sensor with
respect to the ego vehicle coordinate system. The default value corresponds to a lidar
sensor mounted on a sedan, at the center of the roof's front edge. Units are in
meters.

**Sensor's height (m)** — Height of lidar sensor

`1.6`

(default) | positive scalar

Height of the lidar sensor above the ground plane, specified as a positive scalar.
The **Sensor's (x,y) position (m)** and **Sensor's height
(m)** parameters define the coordinates of the lidar sensor with respect to
the ego vehicle coordinate system. The default value corresponds to a lidar sensor
mounted on a sedan, at the center of the roof front edge. Units are in meters.

**Yaw angle of sensor mounted on ego vehicle (deg)** — Yaw angle of lidar sensor

`0`

(default) | real-valued scalar

Yaw angle of the lidar sensor, specified as a real-valued scalar. The
*yaw angle* is the angle between the center line of the ego
vehicle and the downrange axis of the lidar sensor. A positive yaw angle corresponds
to a clockwise rotation when you look in the positive direction of the
*z*-axis of the ego vehicle coordinate system. Units are in
degrees.

**Pitch angle of sensor mounted on ego vehicle (deg)** — Pitch angle of lidar sensor

`0`

(default) | real-valued scalar

Pitch angle of the lidar sensor, specified as a real-valued scalar. The
*pitch angle* is the angle between the downrange axis of the
lidar sensor and the *xy*-plane of the ego vehicle coordinate system.
A positive pitch angle corresponds to a clockwise rotation when you look in the
positive direction of the *y*-axis of the ego vehicle coordinate
system. Units are in degrees.

**Roll angle of sensor mounted on ego vehicle (deg)** — Roll angle of lidar sensor

`0`

(default) | real-valued scalar

Roll angle of the lidar sensor, specified as a real-valued scalar. The
*roll angle* is the angle of rotation of the downrange axis of
the lidar sensor around the *x*-axis of the ego vehicle coordinate
system. A positive roll angle corresponds to a clockwise rotation when you look in the
positive direction of the *x*-axis of the ego vehicle coordinate
system. Units are in degrees.

**Point Cloud Reporting**

**Coordinate system used to report point cloud** — Coordinate system of reported detections

`Ego Cartesian`

(default) | `Sensor Cartesian`

Coordinate system of reported detections, specified as one of these values:

`Ego Cartesian`

— Detections are reported in the ego vehicle Cartesian coordinate system.`Sensor Cartesian`

— Detections are reported in the sensor Cartesian coordinate system.

**Include ego vehicle in generated point cloud** — Include ego vehicle in point cloud

`on`

(default) | `off`

Select this parameter to include the ego vehicle in the generated point cloud.

**ActorID of ego vehicle** — `ActorID`

value of ego vehicle

`1`

(default) | positive integer

`ActorID`

value of the ego vehicle, specified as a positive
integer. `ActorID`

is the unique identifier for an actor. This
parameter must be a valid `ActorID`

from the input **Actor
** bus.

#### Dependencies

To enable this parameter, select the **Include ego vehicle in generated
point cloud** parameter.

**Include roads in generated point cloud** — Include roads in point cloud

`on`

(default) | `off`

Select this parameter to include the roads in the generated point cloud.

**Source of actor profiles** — Source of actor profiles

`From Scenario Reader block`

(default) | `From workspace`

Source of actor profiles, which are the physical and radar characteristics of all actors in the driving scenario, specified as one of these options:

`From Scenario Reader block`

— The block obtains the actor profiles from the scenario specified by the Scenario Reader block.`From workspace`

— The block obtains the actor profiles from the MATLAB or model workspace variable specified by the**MATLAB or model workspace variable name**parameter.

**MATLAB or model workspace variable name** — Variable name of actor profiles

`actor_profiles`

(default) | valid variable name

Variable name of actor profiles, specified as the name of a MATLAB or model workspace variable containing actor profiles.

Actor profiles are the physical and radar characteristics of all actors in a driving scenario and are specified as a structure or structure array.

If the actor profiles variable contains a single structure, then all actors specified in the input

**Actors**bus use this profile.If the actor profiles variable is a structure array, then each actor specified in the input

**Actors**bus must have a unique actor profile.

To generate an array of structures for your driving scenario, use the `actorProfiles`

function. The table shows the valid structure fields. If
you do not specify a field, the fields are set to their default values.

Field | Description |
---|---|

`ActorID` | Scenario-defined actor identifier, specified as a positive integer. |

`ClassID` | Classification identifier, specified as a nonnegative integer. `0`
represents an object of an unknown or unassigned class. |

`Length` | Length of actor, specified as a positive real-valued scalar. Units are in meters. |

`Width` | Width of actor, specified as a positive real-valued scalar. Units are in meters. |

`Height` | Height of actor, specified as a positive real-valued scalar. Units are in meters. |

`OriginOffset` | Offset of actor's rotational center from its geometric center, specified as a real-valued
vector of the form [x, y,
z]. The rotational center, or origin, is located at the
bottom center of the actor. For vehicles, the rotational center is the point on
the ground beneath the center of the rear axle. Units are in meters. |

`MeshVertices` | Mesh vertices of actor, specified as an
n-by-3 real-valued matrix of vertices.
Each row in the matrix defines a point in 3-D space. |

`MeshFaces` | Mesh faces of actor, specified as an
m-by-3 matrix of integers. Each row of
`MeshFaces` represents a triangle defined by the vertex
IDs, which are the row numbers of vertices. |

`RCSPattern` | Radar cross-section (RCS) pattern of actor, specified as a
`numel(RCSElevationAngles)` -by-`numel(RCSAzimuthAngles)`
real-valued matrix. Units are in decibels per square meter. |

`RCSAzimuthAngles` | Azimuth angles corresponding to rows of `RCSPattern` , specified as a vector
of values in the range [–180, 180]. Units are in degrees. |

`RCSElevationAngles` | Elevation angles corresponding to rows of `RCSPattern` , specified as a
vector of values in the range [–90, 90]. Units are in degrees. |

For complete definitions of the structure fields, see the `actor`

and `vehicle`

functions.

#### Dependencies

To enable this parameter, set the **Source of actor profiles**
parameter to `From workspace`

.

### Measurements

**Settings**

**Maximum detection range (m)** — Maximum detection range

`120`

(default) | positive scalar

Maximum detection range of the lidar sensor, specified as a positive scalar. The sensor cannot detect actors beyond this range. This parameter also determines the extent of the road mesh. Units are in meters.

**Range accuracy (m)** — Accuracy of range measurements

`0.002`

(default) | positive scalar

Accuracy of range measurements, specified as a positive scalar. Units are in meters.

**Azimuthal resolution of lidar (deg)** — Azimuthal resolution of lidar sensor

`0.16`

(default) | positive scalar

Azimuthal resolution of the lidar sensor, specified as a positive scalar. The azimuthal resolution defines the minimum separation in azimuth angle at which the lidar can distinguish between two targets. Units are in degrees.

**Elevation resolution of lidar (deg)** — Elevation resolution of lidar sensor

`1.25`

(default) | positive scalar

Elevation resolution of the lidar sensor, specified as a positive scalar. The elevation resolution defines the minimum separation in elevation angle at which the lidar can distinguish between two targets. Units are in degrees.

**Azimuthal limits of lidar (deg)** — Azimuthal limits of lidar sensor

`[-180 180]`

(default) | 1-by-2 real-valued vector of form [*min*,
*max*]

Azimuthal limits of the lidar sensor, specified as a 1-by-2 real-valued vector of
the form [*min*, *max*]. Units are in
degrees.

**Elevation limits of lidar (deg)** — Elevation limits of lidar sensor

`[-20 20]`

(default) | 1-by-2 real-valued vector of form [*min*,
*max*]

Elevation limits of the lidar sensor, specified as a 1-by-2 real-valued vector of
the form [*min*, *max*]. Units are in
degrees.

**Add noise to measurements** — Add noise to measurements

`on`

(default) | `off`

Select this parameter to add noise to lidar sensor measurements. When you clear this parameter, the measurements have no noise.

## Version History

**Introduced in R2020b**

## See Also

### Apps

### Blocks

### Objects

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