chrono::ros::ChROSCameraHandler Class Reference

Description

Handler for publishing camera images to ROS via IPC communication.

PUBLISHER PATTERN (Chrono → ROS):

• Main process: Extracts RGBA8 image data from ChCameraSensor
• Main process: Serializes metadata + pixel data into byte vector
• Subprocess: Deserializes and publishes as sensor_msgs::msg::Image

Data flow: ChCameraSensor → Main process → IPC → Subprocess → ROS topic

Implementation files:

• ChROSCameraHandler.cpp: Main process logic (extract and serialize)
• ChROSCameraHandler_ros.cpp: Subprocess ROS publisher
• ChROSCameraHandler_ipc.h: IPC data structure definition

To implement a similar sensor publisher:

1. Create IPC struct in _ipc.h with sensor metadata (plain C++ types)
2. In handler.cpp: Extract sensor data in GetSerializedData()
3. Serialize metadata + raw data to byte vector
4. In _ros.cpp: Deserialize, create ROS message, publish
5. Register with CHRONO_ROS_REGISTER_HANDLER macro
6. Add message type to ChROSIPCMessage.h enum
7. Add handler recognition to ChROSManager::GetHandlerMessageType()

#include <ChROSCameraHandler.h>

Inheritance diagram for chrono::ros::ChROSCameraHandler:

Collaboration diagram for chrono::ros::ChROSCameraHandler:

Public Member Functions
	ChROSCameraHandler (std::shared_ptr< chrono::sensor::ChCameraSensor > camera, const std::string &topic_name)
	Constructor with automatic update rate from sensor.
	ChROSCameraHandler (double update_rate, std::shared_ptr< chrono::sensor::ChCameraSensor > camera, const std::string &topic_name)
	Constructor with custom update rate.
virtual bool	Initialize (std::shared_ptr< ChROSInterface > interface) override
	Initialize handler (called once at startup in main process) In IPC mode, validates sensor has required filter, but doesn't create ROS publisher Subprocess will create the actual ROS publisher.
virtual ipc::MessageType	GetMessageType () const override
	Get the message type of this handler.
virtual std::vector< uint8_t >	GetSerializedData (double time) override
	Extract and serialize camera image data for IPC transmission Called in main process at update_rate frequency Returns metadata + pixel data as byte vector.
Public Member Functions inherited from chrono::ros::ChROSHandler
virtual	~ChROSHandler ()=default
	Destructor for the ChROSHandler.
const double	GetUpdateRate () const
	Get the period which this handler operates at.
const uint64_t	GetTickCount () const
	Get the number of times Tick() has been called.
virtual bool	IsPublisher () const
	Check if this handler is a publisher (data flows from Chrono to ROS) Default is true.
virtual void	PublishFromSerialized (const std::vector< uint8_t > &data, std::shared_ptr< ChROSInterface > interface)
	Publish data to ROS from serialized bytes.
virtual void	ApplyFromSerialized (const std::vector< uint8_t > &data)
	Apply data to Chrono from serialized bytes.
virtual void	SubscribeAndForward (std::shared_ptr< ChROSInterface > interface, std::function< void(const std::vector< uint8_t > &)> callback)
	Setup subscriber in subprocess to send data back to main process.
virtual void	HandleIncomingMessage (const ipc::Message &msg)
	Handle incoming IPC message from ROS subscriber (bidirectional communication).
virtual bool	SupportsIncomingMessages () const
	Returns true if this handler processes incoming IPC messages.

Additional Inherited Members
Public Types inherited from chrono::ros::ChROSHandler
typedef chrono::ros::ipc::MessageType	MessageType
	Get the message type of this handler.
Protected Member Functions inherited from chrono::ros::ChROSHandler
	ChROSHandler (double update_rate)
	Constructor for the ChROSHandler.
void	IncrementTickCount ()
	Increment the tick count.

Constructor & Destructor Documentation

ChROSCameraHandler() [1/2]

chrono::ros::ChROSCameraHandler::ChROSCameraHandler	(	std::shared_ptr< chrono::sensor::ChCameraSensor >	camera,
		const std::string &	topic_name
	)

Constructor with automatic update rate from sensor.

Parameters

camera	Camera sensor to publish data from
topic_name	ROS topic to publish images to

ChROSCameraHandler() [2/2]

chrono::ros::ChROSCameraHandler::ChROSCameraHandler	(	double	update_rate,
		std::shared_ptr< chrono::sensor::ChCameraSensor >	camera,
		const std::string &	topic_name
	)

Constructor with custom update rate.

Parameters

update_rate	Rate at which to publish images (Hz)
camera	Camera sensor to publish data from
topic_name	ROS topic to publish images to

Member Function Documentation

GetMessageType()

virtual ipc::MessageType chrono::ros::ChROSCameraHandler::GetMessageType ( ) const

inlineoverridevirtual

Get the message type of this handler.

Reimplemented from chrono::ros::ChROSHandler.

GetSerializedData()

std::vector< uint8_t > chrono::ros::ChROSCameraHandler::GetSerializedData ( double  time )

overridevirtual

Extract and serialize camera image data for IPC transmission Called in main process at update_rate frequency Returns metadata + pixel data as byte vector.

Parameters

time	Current simulation time

Returns

Serialized camera data (header + RGBA8 pixels)

Reimplemented from chrono::ros::ChROSHandler.

Initialize()

bool chrono::ros::ChROSCameraHandler::Initialize ( std::shared_ptr< ChROSInterface >  interface )

overridevirtual

Initialize handler (called once at startup in main process) In IPC mode, validates sensor has required filter, but doesn't create ROS publisher Subprocess will create the actual ROS publisher.

Implements chrono::ros::ChROSHandler.

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The documentation for this class was generated from the following files:

• /builds/uwsbel/chrono/src/chrono_ros/handlers/sensor/ChROSCameraHandler.h
• /builds/uwsbel/chrono/src/chrono_ros/handlers/sensor/ChROSCameraHandler.cpp