#include <DepthImageToLaserScan.h>

Public Member Functions
sensor_msgs::LaserScanPtr	convert_msg (const sensor_msgs::ImageConstPtr &depth_msg, const sensor_msgs::CameraInfoConstPtr &info_msg)
	DepthImageToLaserScan ()
void	set_output_frame (const std::string output_frame_id)
void	set_range_limits (const float range_min, const float range_max)
void	set_scan_height (const int scan_height)
void	set_scan_time (const float scan_time)
	~DepthImageToLaserScan ()
Private Member Functions
double	angle_between_rays (const cv::Point3d &ray1, const cv::Point3d &ray2) const
template<typename T >
void	convert (const sensor_msgs::ImageConstPtr &depth_msg, const image_geometry::PinholeCameraModel &cam_model, const sensor_msgs::LaserScanPtr &scan_msg, const int &scan_height) const
double	magnitude_of_ray (const cv::Point3d &ray) const
bool	use_point (const float new_value, const float old_value, const float range_min, const float range_max) const
Private Attributes
image_geometry::PinholeCameraModel	cam_model_
	image_geometry helper class for managing sensor_msgs/CameraInfo messages.
std::string	output_frame_id_
	Output frame_id for each laserscan. This is likely NOT the camera's frame_id.
float	range_max_
	Stores the current maximum range to use.
float	range_min_
	Stores the current minimum range to use.
int	scan_height_
	Number of pixel rows to use when producing a laserscan from an area.
float	scan_time_
	Stores the time between scans.

Detailed Description

Definition at line 48 of file DepthImageToLaserScan.h.

Constructor & Destructor Documentation

DepthImageToLaserScan::DepthImageToLaserScan ( )

Definition at line 38 of file DepthImageToLaserScan.cpp.

DepthImageToLaserScan::~DepthImageToLaserScan ( )

Definition at line 41 of file DepthImageToLaserScan.cpp.

Member Function Documentation

double DepthImageToLaserScan::angle_between_rays	(	const cv::Point3d &	ray1,
		const cv::Point3d &	ray2
	)		const `[private]`

Computes the angle between two cv::Point3d

Computes the angle of two cv::Point3d assumed to be vectors starting at the origin (0,0,0). Uses the following equation: angle = arccos(a*b/(|a||b|)) where a = ray1 and b = ray2.

Parameters:

ray1	The first ray
ray2	The second ray

Returns:: The angle between the two rays (in radians)

Definition at line 48 of file DepthImageToLaserScan.cpp.

template<typename T >

void depthimage_to_laserscan::DepthImageToLaserScan::convert	(	const sensor_msgs::ImageConstPtr &	depth_msg,
		const image_geometry::PinholeCameraModel &	cam_model,
		const sensor_msgs::LaserScanPtr &	scan_msg,
		const int &	scan_height
	)		const `[inline, private]`

Converts the depth image to a laserscan using the DepthTraits to assist.

This uses a method to inverse project each pixel into a LaserScan angular increment. This method first projects the pixel forward into Cartesian coordinates, then calculates the range and angle for this point. When multiple points coorespond to a specific angular measurement, then the shortest range is used.

Parameters:

depth_msg	The UInt16 or Float32 encoded depth message.
cam_model	The image_geometry camera model for this image.
scan_msg	The output LaserScan.
scan_height	The number of vertical pixels to feed into each angular_measurement.

Definition at line 170 of file DepthImageToLaserScan.h.

sensor_msgs::LaserScanPtr DepthImageToLaserScan::convert_msg	(	const sensor_msgs::ImageConstPtr &	depth_msg,
		const sensor_msgs::CameraInfoConstPtr &	info_msg
	)

Converts the information in a depth image (sensor_msgs::Image) to a sensor_msgs::LaserScan.

This function converts the information in the depth encoded image (UInt16 or Float32 encoding) into a sensor_msgs::LaserScan as accurately as possible. To do this, it requires the synchornized Image/CameraInfo pair associated with the image.

Parameters:

depth_msg	UInt16 or Float32 encoded depth image.
info_msg	CameraInfo associated with depth_msg

Returns:: sensor_msgs::LaserScanPtr for the center row(s) of the depth image.

Definition at line 83 of file DepthImageToLaserScan.cpp.

double DepthImageToLaserScan::magnitude_of_ray ( const cv::Point3d & ray ) const [private]

Computes euclidean length of a cv::Point3d (as a ray from origin)

This function computes the length of a cv::Point3d assumed to be a vector starting at the origin (0,0,0).

Parameters:

ray	The ray for which the magnitude is desired.

Returns:: Returns the magnitude of the ray.

Definition at line 44 of file DepthImageToLaserScan.cpp.

void DepthImageToLaserScan::set_output_frame ( const std::string output_frame_id )

Sets the frame_id for the output LaserScan.

Output frame_id for the LaserScan. Will probably NOT be the same frame_id as the depth image. Example: For OpenNI cameras, this should be set to 'camera_depth_frame' while the camera uses 'camera_depth_optical_frame'.

Parameters:

output_frame_id Frame_id to use for the output sensor_msgs::LaserScan.

Definition at line 160 of file DepthImageToLaserScan.cpp.

void DepthImageToLaserScan::set_range_limits	(	const float	range_min,
		const float	range_max
	)

Sets the minimum and maximum range for the sensor_msgs::LaserScan.

range_min is used to determine how close of a value to allow through when multiple radii correspond to the same angular increment. range_max is used to set the output message.

Parameters:

range_min	Minimum range to assign points to the laserscan, also minimum range to use points in the output scan.
range_max	Maximum range to use points in the output scan.

Definition at line 151 of file DepthImageToLaserScan.cpp.

void DepthImageToLaserScan::set_scan_height ( const int scan_height )

Sets the number of image rows to use in the output LaserScan.

scan_height is the number of rows (pixels) to use in the output. This will provide scan_height number of radii for each angular increment. The output scan will output the closest radius that is still not smaller than range_min. This function can be used to vertically compress obstacles into a single LaserScan.

Parameters:

scan_height Number of pixels centered around the center of the image to compress into the LaserScan.

Definition at line 156 of file DepthImageToLaserScan.cpp.

void DepthImageToLaserScan::set_scan_time ( const float scan_time )

Sets the scan time parameter.

This function stores the desired value for scan_time. In sensor_msgs::LaserScan, scan_time is defined as "time between scans [seconds]". This value is not easily calculated from consquetive messages, and is thus left to the user to set correctly.

Parameters:

scan_time The value to use for outgoing sensor_msgs::LaserScan.

Definition at line 147 of file DepthImageToLaserScan.cpp.

bool DepthImageToLaserScan::use_point	(	const float	new_value,
		const float	old_value,
		const float	range_min,
		const float	range_max
	)		const `[private]`

Determines whether or not new_value should replace old_value in the LaserScan.

Uses the values of range_min, and range_max to determine if new_value is a valid point. Then it determines if new_value is 'more ideal' (currently shorter range) than old_value.

Parameters:

new_value	The current calculated range.
old_value	The current range in the output LaserScan.
range_min	The minimum acceptable range for the output LaserScan.
range_max	The maximum acceptable range for the output LaserScan.