CameraInfo Manager class. More...

#include <camera_info_manager.h>

Public Member Functions
	CameraInfoManager (ros::NodeHandle nh, const std::string &cname="camera", const std::string &url="")

sensor_msgs::CameraInfo	getCameraInfo (void)

bool	isCalibrated (void)

bool	loadCameraInfo (const std::string &url)

std::string	resolveURL (const std::string &url, const std::string &cname)

bool	setCameraInfo (const sensor_msgs::CameraInfo &camera_info)

bool	setCameraName (const std::string &cname)

bool	validateURL (const std::string &url)

Private Types
enum	url_type_t { URL_empty = 0, URL_file, URL_package, URL_invalid, URL_flash }

Private Member Functions
std::string	getPackageFileName (const std::string &url)

bool	loadCalibration (const std::string &url, const std::string &cname)

bool	loadCalibrationFile (const std::string &filename, const std::string &cname)

url_type_t	parseURL (const std::string &url)

bool	saveCalibration (const sensor_msgs::CameraInfo &new_info, const std::string &url, const std::string &cname)

bool	saveCalibrationFile (const sensor_msgs::CameraInfo &new_info, const std::string &filename, const std::string &cname)

bool	setCameraInfoService (sensor_msgs::SetCameraInfo::Request &req, sensor_msgs::SetCameraInfo::Response &rsp)

Private Attributes
sensor_msgs::CameraInfo	cam_info_
	current CameraInfo More...

std::string	camera_name_
	camera name More...

ros::ServiceServer	info_service_
	set_camera_info service More...

bool	loaded_cam_info_
	cam_info_ load attempted More...

boost::mutex	mutex_
	mutual exclusion lock for private data More...

ros::NodeHandle	nh_
	node handle for service More...

std::string	url_
	URL for calibration data. More...

Detailed Description

CameraInfo Manager class.

Provides CameraInfo, handles the sensor_msgs/SetCameraInfo service requests, saves and restores sensor_msgs/CameraInfo data.

ROS Service

set_camera_info (sensor_msgs/SetCameraInfo) stores calibration information

Typically, these service requests are made by a calibration package, such as:

http://www.ros.org/wiki/camera_calibration

The calling node must invoke ros::spin() or ros::spinOnce() in some thread, so CameraInfoManager can handle arriving service requests.

Camera Name

The device driver sets a camera name via the CameraInfoManager::CameraInfoManager constructor or the setCameraName() method. This name is written when CameraInfo is saved, and checked when data are loaded, with a warning logged if the name read does not match.

Syntax: a camera name contains any combination of alphabetic, numeric and '_' characters. Case is significant.

Camera drivers may use any syntactically valid name they please. Where possible, it is best for the name to be unique to the device, such as a GUID, or the make, model and serial number. Any parameters that affect calibration, such as resolution, focus, zoom, etc., may also be included in the name, uniquely identifying each CameraInfo file.

Beginning with Electric Emys, the camera name can be resolved as part of the URL, allowing direct access to device-specific calibration information.

Uniform Resource Locator

The location for getting and saving calibration data is expressed by Uniform Resource Locator. The driver defines a URL via the CameraInfoManager::CameraInfoManager constructor or the loadCameraInfo() method. Many drivers provide a ~camera_info_url parameter so users may customize this URL, but that is handled outside this class.

Typically, cameras store calibration information in a file, which can be in any format supported by camera_calibration_parsers. Currently, that includes YAML and Videre INI files, identified by their .yaml or .ini extensions as shown in the examples. These file formats are described here:

http://www.ros.org/wiki/camera_calibration_parsers#File_formats

Example URL syntax:

file:///full/path/to/local/file.yaml
file:///full/path/to/videre/file.ini
package://camera_info_manager/tests/test_calibration.yaml
package://ros_package_name/calibrations/camera3.yaml

The file: URL specifies a full path name in the local system. The package: URL is handled the same as file:, except the path name is resolved relative to the location of the named ROS package, which must be reachable via $ROS_PACKAGE_PATH.

Beginning with Electric Emys, the URL may contain substitution variables delimited by ${...}, including:

${NAME} resolved to the current camera name defined by the device driver.
${ROS_HOME} resolved to the $ROS_HOME environment variable if defined, ~/.ros if not.

Resolution is done in a single pass through the URL string. Variable values containing substitutable strings are not resolved recursively. Unrecognized variable names are treated literally with no substitution, but an error is logged.

Examples with variable substitution:

package://my_cameras/calibrations/${NAME}.yaml
file://${ROS_HOME}/camera_info/left_front_camera.yaml

In C-turtle and Diamondback, if the URL was empty, no calibration data were loaded, and any data provided via set_camera_info would be stored in:

file:///tmp/calibration_${NAME}.yaml

Beginning in Electric, the default URL changed to:

file://${ROS_HOME}/camera_info/${NAME}.yaml.

If that file exists, its contents are used. Any new calibration will be stored there, missing parent directories being created if necessary and possible.

Loading Calibration Data

Prior to Fuerte, calibration information was loaded in the constructor, and again each time the URL or camera name was updated. This frequently caused logging of confusing and misleading error messages.

Beginning in Fuerte, camera_info_manager loads nothing until the loadCameraInfo(), isCalibrated() or getCameraInfo() method is called. That suppresses bogus error messages, but allows (valid) load errors to occur during the first getCameraInfo(), or isCalibrated(). To avoid that, do an explicit loadCameraInfo() first.

Definition at line 174 of file camera_info_manager.h.

Member Enumeration Documentation

enum camera_info_manager::CameraInfoManager::url_type_t

private

Enumerator
URL_empty
URL_file
URL_package
URL_invalid
URL_flash

Definition at line 194 of file camera_info_manager.h.

Constructor & Destructor Documentation

camera_info_manager::CameraInfoManager::CameraInfoManager	(	ros::NodeHandle	nh,
		const std::string &	cname = `"camera"`,
		const std::string &	url = `""`
	)

Constructor

Parameters

nh	node handle, normally for the driver's streaming name space ("camera"). The service name is relative to this handle. Nodes supporting multiple cameras may use subordinate names, like "left/camera" and "right/camera".
cname	default camera name
url	default Uniform Resource Locator for loading and saving data.

Definition at line 78 of file camera_info_manager.cpp.

Member Function Documentation

sensor_msgs::CameraInfo camera_info_manager::CameraInfoManager::getCameraInfo ( void )

Get the current CameraInfo data.

If CameraInfo has not yet been loaded, an attempt must be made here. To avoid that, ensure that loadCameraInfo() ran previously. If the load is attempted but fails, an empty CameraInfo will be supplied.

The matrices are all zeros if no calibration is available. The image pipeline handles that as uncalibrated data.

Warning: The caller must fill in the message Header of the CameraInfo returned. The time stamp and frame_id should normally be the same as the corresponding Image message Header fields.

Definition at line 106 of file camera_info_manager.cpp.

std::string camera_info_manager::CameraInfoManager::getPackageFileName ( const std::string & url )

private

Get file name corresponding to a package: URL.

Parameters

url	a copy of the Uniform Resource Locator

Returns: file name if package found, "" otherwise

Definition at line 140 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::isCalibrated ( void )

Is the current CameraInfo calibrated?

If CameraInfo has not yet been loaded, an attempt must be made here. To avoid that, ensure that loadCameraInfo() ran previously. If the load failed, CameraInfo will be empty and this predicate will return false.

Returns: true if the current CameraInfo is calibrated.

Definition at line 173 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::loadCalibration	(	const std::string &	url,
		const std::string &	cname
	)

private

Load CameraInfo calibration data (if any).

Precondition: mutex_ unlocked

Parameters

url	a copy of the Uniform Resource Locator
cname	is a copy of the camera_name_

Returns: true if URL contains calibration data.

sets cam_info_, if successful

Definition at line 210 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::loadCalibrationFile	(	const std::string &	filename,
		const std::string &	cname
	)

private

Load CameraInfo calibration data from a file.

Precondition: mutex_ unlocked

Parameters

filename	containing CameraInfo to read
cname	is a copy of the camera_name_

Returns: true if URL contains calibration data.

Sets cam_info_, if successful

Definition at line 268 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::loadCameraInfo ( const std::string & url )

Set a new URL and load its calibration data (if any).

If multiple threads call this method simultaneously with different URLs, there is no guarantee which will prevail.

Parameters

url	new Uniform Resource Locator for CameraInfo.

Returns: true if new URL contains calibration data.

Postcondition: loaded_cam_info_ true (meaning a load was attempted, even if it failed); cam_info_ updated, if successful.

Definition at line 310 of file camera_info_manager.cpp.

CameraInfoManager::url_type_t camera_info_manager::CameraInfoManager::parseURL ( const std::string & url )

private

Parse calibration Uniform Resource Locator.

Parameters

url	string to parse

Returns: URL type

Note: Recognized but unsupported URL types have enum values >= URL_invalid.

Definition at line 407 of file camera_info_manager.cpp.

std::string camera_info_manager::CameraInfoManager::resolveURL	(	const std::string &	url,
		const std::string &	cname
	)

Resolve Uniform Resource Locator string.

Parameters

url	a copy of the Uniform Resource Locator, which may include `${...}` substitution variables.
cname	is a copy of the camera_name_

Returns: a copy of the URL with any variable information resolved.

Definition at line 333 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::saveCalibration	(	const sensor_msgs::CameraInfo &	new_info,
		const std::string &	url,
		const std::string &	cname
	)

private

Save CameraInfo calibration data.

Precondition: mutex_ unlocked

Parameters

new_info	contains CameraInfo to save
url	is a copy of the URL storage location (if empty, use `file://${ROS_HOME}/camera_info/${NAME}.yaml`)
cname	is a copy of the camera_name_

Returns: true, if successful

Definition at line 443 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::saveCalibrationFile	(	const sensor_msgs::CameraInfo &	new_info,
		const std::string &	filename,
		const std::string &	cname
	)

private

Save CameraInfo calibration data to a file.

Precondition: mutex_ unlocked

Parameters

new_info	contains CameraInfo to save
filename	is local file to store data
cname	is a copy of the camera_name_

Returns: true, if successful

Definition at line 493 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::setCameraInfo ( const sensor_msgs::CameraInfo & camera_info )

Set the camera info manually

Parameters

camera_info new camera calibration data

Returns: true if new camera info is set

Postcondition: cam_info_ updated, if valid;

Definition at line 630 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::setCameraInfoService	(	sensor_msgs::SetCameraInfo::Request &	req,
		sensor_msgs::SetCameraInfo::Response &	rsp
	)

private

Callback for SetCameraInfo request.

Always updates cam_info_ class variable, even if save fails.

Parameters

req	SetCameraInfo request message
rsp	SetCameraInfo response message

Returns: true if message handled

Definition at line 558 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::setCameraName ( const std::string & cname )

Set a new camera name.

Parameters

cname new camera name to use for saving calibration data

Returns: true if new name has valid syntax; valid names contain only alphabetic, numeric, or '_' characters.

Postcondition: cam_name_ updated, if valid; since it may affect the URL, cam_info_ will be reloaded before being used again.

Definition at line 597 of file camera_info_manager.cpp.

bool camera_info_manager::CameraInfoManager::validateURL ( const std::string & url )

Validate URL syntax.

Parameters

url	Uniform Resource Locator to check

Returns: true if URL syntax is supported by CameraInfoManager (although the resource need not actually exist)

Definition at line 647 of file camera_info_manager.cpp.

Member Data Documentation

sensor_msgs::CameraInfo camera_info_manager::CameraInfoManager::cam_info_

private

current CameraInfo

Definition at line 236 of file camera_info_manager.h.

std::string camera_info_manager::CameraInfoManager::camera_name_

private

camera name

Definition at line 234 of file camera_info_manager.h.

ros::ServiceServer camera_info_manager::CameraInfoManager::info_service_

private

set_camera_info service

Definition at line 233 of file camera_info_manager.h.

bool camera_info_manager::CameraInfoManager::loaded_cam_info_

private

cam_info_ load attempted

Definition at line 237 of file camera_info_manager.h.

boost::mutex camera_info_manager::CameraInfoManager::mutex_

private

mutual exclusion lock for private data

This non-recursive mutex is only held for a short time while accessing or changing private class variables. To avoid deadlocks and contention, it is never held during I/O or while invoking a callback. Most private methods operate on copies of class variables, keeping the mutex hold time short.

Definition at line 229 of file camera_info_manager.h.

ros::NodeHandle camera_info_manager::CameraInfoManager::nh_

private

node handle for service

Definition at line 232 of file camera_info_manager.h.

std::string camera_info_manager::CameraInfoManager::url_

private

URL for calibration data.

Definition at line 235 of file camera_info_manager.h.

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

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation