Simulation 3D Fisheye Camera

Fisheye camera sensor model in 3D simulation environment

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Libraries:
UAV Toolbox / Simulation 3D
Automated Driving Toolbox / Simulation 3D
Simulink 3D Animation / Simulation 3D / Sensors

Description

Note

Simulating models with the Simulation 3D Fisheye Camera block requires Simulink^® 3D Animation™ and Computer Vision Toolbox™.

The Simulation 3D Fisheye Camera block provides an interface to a camera with a fisheye lens in a 3D simulation environment. This environment is rendered using the Unreal Engine^® from Epic Games^®. The sensor is based on the fisheye camera model proposed by Scaramuzza [1]. This model supports a field of view of up to 195 degrees. The block outputs an image with the specified camera distortion and size. You can also output the location and orientation of the camera in the world coordinate system of the scene.

If you set Sample time to -1, the block uses the sample time specified in the Simulation 3D Scene Configuration block. To use this sensor, you must include a Simulation 3D Scene Configuration block in your model.

Tip

The Simulation 3D Scene Configuration block must execute before the Simulation 3D Fisheye Camera block. That way, the Unreal Engine 3D visualization environment prepares the data before the Simulation 3D Fisheye Camera block receives it. To check the block execution order, right-click the blocks and select Properties. On the General tab, confirm these Priority settings:

• Simulation 3D Scene Configuration — 0

• Simulation 3D Fisheye Camera — 1

For more information about execution order, see How Unreal Engine Simulation for Automated Driving Works.

Examples

Simulate Simple Driving Scenario and Sensor in Unreal Engine Environment

Learn the basics of configuring and simulating scenes, vehicles, and sensors in a virtual environment rendered using the Unreal Engine from Epic Games.

• Open Live Script

Ports

Input

Rel Translation — Relative translation of sensor from mounting point (m)

[0 0 0] (default) | real-valued 1-by-3 vector of form [X Y Z]

Relative translation of the sensor from its mounting point on the vehicle, in meters, specified as a real-valued 1-by-3 vector of the form [X Y Z].

Dependencies

To enable this port, select the Input parameter next to the Relative translation [X, Y, Z] (m) parameter. When you select Input, the Relative translation [X, Y, Z] (m) parameter specifies the initial relative translation and the Rel Translation port specifies the relative translation during simulation. For more details, see Sensor Position Transformation.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Rel Rotation — Relative rotation of sensor from mounting point (deg)

[0 0 0] (default) | real-valued 1-by-3 vector of form [Roll Pitch Yaw]

Relative rotation of the sensor from its mounting point on the vehicle, in degrees, specified as a real-valued 1-by-3 vector of the form [Roll Pitch Yaw].

Dependencies

To enable this port, select the Input parameter next to the Relative rotation [Roll, Pitch, Yaw] (deg) parameter. When you select Input, the Relative translation [Roll, Pitch, Yaw] (deg) parameter specifies the initial relative rotation and the Rel Rotation port specifies the relative rotation during simulation. For more details, see Sensor Position Transformation.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Output

Image — 3D output camera image

m-by-n-by-3 array of RGB triplet values

3D output camera image, returned as an m-by-n-by-3 array of RGB triplet values. m is the vertical resolution of the image, and n is the horizontal resolution of the image.

Data Types: int8 | uint8

Translation — Sensor location

real-valued 1-by-3 vector

Sensor location along the X-axis, Y-axis, and Z-axis of the scene. The Translation values are in the world coordinates of the scene. In this coordinate system, the Z-axis points up from the ground. Units are in meters.

Dependencies

To enable this port, on the Ground Truth tab, select Output location (m) and orientation (rad).

Data Types: double

Rotation — Sensor orientation

real-valued 1-by-3 vector

Roll, pitch, and yaw sensor orientation about the X-axis, Y-axis, and Z-axis of the scene. The Rotation values are in the world coordinates of the scene. These values are positive in the clockwise direction when looking in the positive directions of these axes. Units are in radians.

Dependencies

To enable this port, on the Ground Truth tab, select Output location (m) and orientation (rad).

Data Types: double

Parameters

Mounting

Sensor identifier — Unique sensor identifier

1 (default) | positive integer

Specify the unique identifier of the sensor. In a multisensor system, the sensor identifier enables you to distinguish between sensors. When you add a new sensor block to your model, the Sensor identifier of that block is N + 1, where N is the highest Sensor identifier value among the existing sensor blocks in the model.

Example: 2

Parent name — Name of parent vehicle

Scene Origin (default) | vehicle name

Name of the parent to which the sensor is mounted, specified as Scene Origin or as the name of a vehicle in your model. The vehicle names that you can select correspond to the Name parameters of the simulation 3D vehicle blocks in your model. If you select Scene Origin, the block places a sensor at the scene origin.

Example: SimulinkVehicle1

Mounting location — Sensor mounting location

Origin (default) | Front bumper | Rear bumper | Right mirror | Left mirror | Rearview mirror | Hood center | Roof center | ...

Sensor mounting location.

• When Parent name is Scene Origin, the block mounts the sensor to the origin of the scene. You can set the Mounting location to Origin only. During simulation, the sensor remains stationary.

• When Parent name is the name of a vehicle, the block mounts the sensor to one of the predefined mounting locations described in the table. During simulation, the sensor travels with the vehicle.

Vehicle Mounting Location	Description	Orientation Relative to Vehicle Origin [Roll, Pitch, Yaw] (deg)
Origin	Forward-facing sensor mounted to the vehicle origin, which is on the ground and at the geometric center of the vehicle (see Coordinate Systems for Unreal Engine Simulation in Automated Driving Toolbox)	[0, 0, 0]
Front bumper Front center	Forward-facing sensor mounted to the front bumper	[0, 0, 0]
Rear bumper Rear center	Backward-facing sensor mounted to the rear bumper	[0, 0, 180]
Right mirror	Downward-facing sensor mounted to the right side-view mirror	[0, –90, 0]
Left mirror	Downward-facing sensor mounted to the left side-view mirror	[0, –90, 0]
Rearview mirror	Forward-facing sensor mounted to the rearview mirror, inside the vehicle	[0, 0, 0]
Hood center	Forward-facing sensor mounted to the center of the hood	[0, 0, 0]
Roof center	Forward-facing sensor mounted to the center of the roof	[0, 0, 0]

Roll, pitch, and yaw are clockwise-positive when looking in the positive direction of the X-axis, Y-axis, and Z-axis, respectively. When looking at a vehicle from above, the yaw angle (the orientation angle) is counterclockwise-positive because you are looking in the negative direction of the axis.

The X-Y-Z mounting location of the sensor relative to the vehicle depends on the vehicle type. To specify the vehicle type, use the Type parameter of the Simulation 3D Vehicle with Ground Following to which you mount the sensor. To obtain the X-Y-Z mounting locations for a vehicle type, see the reference page for that vehicle.

To determine the location of the sensor in world coordinates, open the sensor block. Then, on the Ground Truth tab, select the Output location (m) and orientation (rad) parameter and inspect the data from the Translation output port.

Specify offset — Specify offset from mounting location

off (default) | on

Select this parameter to specify an offset from the mounting location by using the Relative translation [X, Y, Z] (m) and Relative rotation [Roll, Pitch, Yaw] (deg) parameters.

Relative translation [X, Y, Z] (m) — Translation offset relative to mounting location

[0, 0, 0] (default) | real-valued 1-by-3 vector

Translation offset relative to the mounting location of the sensor, specified as a real-valued 1-by-3 vector of the form [X, Y, Z]. Units are in meters.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the vehicle coordinate system, where:

• The X-axis points forward from the vehicle.

• The Y-axis points to the left of the vehicle, as viewed when looking in the forward direction of the vehicle.

• The Z-axis points up.

The origin is the mounting location specified in the Mounting location parameter. This origin is different from the vehicle origin, which is the geometric center of the vehicle.

If you mount the sensor to the scene origin by setting Parent name to Scene Origin, then X, Y, and Z are in the world coordinates of the scene.

For more details about the vehicle and world coordinate systems, see Coordinate Systems for Unreal Engine Simulation in Automated Driving Toolbox.

Example: [0,0,0.01]

Adjust Relative Translation During Simulation

To adjust the relative translation of the sensor during simulation, enable the Rel Translation input port by selecting the Input parameter next to the Relative translation [X, Y, Z] (m) parameter. When you enable the Rel Translation port, the Relative translation [X, Y, Z] (m) parameter specifies the initial relative translation of the sensor and the Rel Translation port specifies the relative translation of the sensor during simulation. For more details about the relative translation and rotation of this sensor, see Sensor Position Transformation.

Dependencies

To enable this parameter, select Specify offset.

Relative rotation [Roll, Pitch, Yaw] (deg) — Rotational offset relative to mounting location

[0, 0, 0] (default) | real-valued 1-by-3 vector

Rotational offset relative to the mounting location of the sensor, specified as a real-valued 1-by-3 vector of the form [Roll, Pitch, Yaw]. Roll, pitch, and yaw are the angles of rotation about the X-, Y-, and Z-axes, respectively. Units are in degrees.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the vehicle coordinate system, where:

• The X-axis points forward from the vehicle.

• The Y-axis points to the left of the vehicle, as viewed when looking in the forward direction of the vehicle.

• The Z-axis points up.

• Roll, pitch, and yaw are clockwise-positive when looking in the forward direction of the X-axis, Y-axis, and Z-axis, respectively. If you view a scene from a 2D top-down perspective, then the yaw angle (also called the orientation angle) is counterclockwise-positive because you are viewing the scene in the negative direction of the Z-axis.

The origin is the mounting location specified in the Mounting location parameter. This origin is different from the vehicle origin, which is the geometric center of the vehicle.

If you mount the sensor to the scene origin by setting Parent name to Scene Origin, then X, Y, and Z are in the world coordinates of the scene.

For more details about the vehicle and world coordinate systems, see Coordinate Systems for Unreal Engine Simulation in Automated Driving Toolbox.

Example: [0,0,10]

Adjust Relative Rotation During Simulation

To adjust the relative rotation of the sensor during simulation, enable the Rel Rotation input port by selecting the Input parameter next to the Relative rotation [Roll, Pitch, Yaw] (deg) parameter. When you enable the Rel Rotation port, the Relative rotation [Roll, Pitch, Yaw] (deg) parameter specifies the initial relative rotation of the sensor and the Rel Rotation port specifies the relative rotation of the sensor during simulation. For more details about the relative translation and rotation of this sensor, see Sensor Position Transformation.

Dependencies

To enable this parameter, select Specify offset.

Sample time — Sample time

-1 (default) | positive scalar

Sample time of the block, in seconds, specified as a positive scalar. The 3D simulation environment frame rate is the inverse of the sample time.

If you set the sample time to -1, the block inherits its sample time from the Simulation 3D Scene Configuration block.

Parameters

These intrinsic camera parameters are equivalent to the properties of a fisheyeIntrinsics object. To obtain the intrinsic parameters for your camera, use the Camera Calibrator app.

For details about the fisheye camera calibration process, see Using the Single Camera Calibrator App and Fisheye Calibration Basics.

Distortion center (pixels) — Center of distortion

[640, 360] (default) | real-valued 1-by-2 vector

Center of distortion, specified as real-valued 2-element vector. Units are in pixels.

Image size (pixels) — Image size produced by camera

[720, 1280] (default) | real-valued 1-by-2 vector of positive integers

Image size produced by the camera, specified as a real-valued 1-by-2 vector of positive integers of the form [mrows,ncols]. Units are in pixels.

Mapping coefficients — Polynomial coefficients for projection function

[320, 0, 0, 0] (default) | real-valued 1-by-4 vector

Polynomial coefficients for the projection function described by Scaramuzza's Taylor model [1], specified as a real-valued 1-by-4 vector of the form [a0 a2 a3 a4].

Example: [320, -0.001, 0, 0]

Stretch matrix — Transforms point from sensor plane to camera plane

[1, 0; 0, 1] (default) | real-valued 2-by-2 matrix

Transforms a point from the sensor plane to a pixel in the camera image plane. The misalignment occurs during the digitization process when the lens is not parallel to sensor.

Example: [0, 1; 0, 1]

Ground Truth

Output location (m) and orientation (rad) — Output location and orientation of sensor

off (default) | on

Select this parameter to output the translation and rotation of the sensor at the Translation and Rotation ports, respectively.

Tips

• To visualize the camera images that are output by the Image port, use a Video Viewer or To Video Display block.

• Because the Unreal Engine can take a long time to start up between simulations, consider logging the signals that the sensors output. You can then use this data to develop perception algorithms in MATLAB^®. See Mark Signals for Logging (Simulink).

  You can also save image data as a video by using a To Multimedia File block. For an example of this setup, see Design Lane Marker Detector Using Unreal Engine Simulation Environment.

Algorithms

Sensor Position Transformation

At each simulation time step, the sensor block transforms the position (translation and rotation) of the sensor by using this equation:

T_Vehicle + T_Mount + T_Offset + T_Port

This equation contains these steps:

1. Take the world coordinate position of the vehicle to which the sensor is mounted. (T_Vehicle)

2. Transform the sensor to the mounting position specified by the Mounting location parameter. (T_Mount)

3. Transform the sensor to the position specified by the Relative translation [X, Y, Z] (m) and Relative rotation [Roll, Pitch, Yaw] (deg) parameters, if enabled. (T_Offset)

   To enable these parameters, select the Specify offset parameter

4. Transform the sensor from the offset position to the position specified by the Translation and Rotation ports. (T_Port)

   To enable these ports, select the Input parameters corresponding to the relative translation and rotation parameters.

References

[1] Scaramuzza, D., A. Martinelli, and R. Siegwart. "A Toolbox for Easy Calibrating Omindirectional Cameras." Proceedings to IEEE International Conference on Intelligent Robots and Systems (IROS 2006). Beijing, China, October 7–15, 2006.

Version History

Introduced in R2019b

R2024a: Requires Simulink 3D Animation

Simulating models with the Simulation 3D Fisheye Camera block requires Simulink 3D Animation.