DICe::Optical_Flow_Initializer Class Reference

an initializer that uses optical flow to predict the next location of the subset (Lucas-Kanade algorithm). This initializer is only intended for the TRACKING_ROUTINE correlation routine More...

#include <DICe_Initializer.h>

Inheritance diagram for DICe::Optical_Flow_Initializer:

Public Member Functions
	Optical_Flow_Initializer (Schema *schema, Teuchos::RCP< Subset > subset)
virtual	~Optical_Flow_Initializer ()
	virtual destructor
virtual void	pre_execution_tasks ()
	see base class description
virtual Status_Flag	initial_guess (const int_t subset_gid, Teuchos::RCP< Local_Shape_Function > shape_function)
	see base class description
size_t	neighbor (const int_t pixel_id, const int_t neighbor_index) const
Status_Flag	set_locations (const int_t subset_gid)
int_t	best_optical_flow_point (scalar_t &best_grad, Teuchos::ArrayRCP< int_t > &def_x, Teuchos::ArrayRCP< int_t > &def_y, Teuchos::ArrayRCP< scalar_t > &gx, Teuchos::ArrayRCP< scalar_t > &gy, std::set< std::pair< int_t, int_t > > &subset_pixels, Teuchos::RCP< std::vector< int_t > > existing_points=Teuchos::null, const bool allow_close_points=false)
bool	is_near_deactivated (const int_t pixel_id)
Public Member Functions inherited from DICe::Initializer
	Initializer (Schema *schema)
	base class constructor
virtual	~Initializer ()
	virtual destructor

Protected Attributes
Teuchos::RCP< Subset >	subset_
	pointer to the subset being initialized
size_t	num_neighbors_
	k-closest neighbors for each point in the set of triads
int_t	window_size_
	size of the window
int_t	half_window_size_
	half the size of the window
std::vector< size_t >	neighbors_
	a strided array of neighbor ids
Teuchos::RCP< kd_tree_2d_t >	kd_tree_
	pointer to the kd-tree used for searching
Teuchos::RCP< Point_Cloud_2D< scalar_t > >	point_cloud_
	pointer to the point cloud used for the neighbor searching
scalar_t	window_coeffs_ [13][13]
	Gauss filter coefficients.
int_t	ref_pt1_x_
	x coord of reference position for optical flow 1
int_t	ref_pt1_y_
	y coord of reference position for optical flow 1
int_t	ref_pt2_x_
	x coord of reference position for optical flow 2
int_t	ref_pt2_y_
	y coord of reference position for optical flow 2
scalar_t	current_pt1_x_
	x coord of current position for optical flow 1
scalar_t	current_pt1_y_
	y coord of current position for optical flow 1
scalar_t	current_pt2_x_
	x coord of current position for optical flow 2
scalar_t	current_pt2_y_
	y coord of current position for optical flow 2
bool	reset_locations_
	flag to reset the optical flow positions
scalar_t	delta_1c_x_
	x comp of vector from optical flow position 1 to the centroid
scalar_t	delta_1c_y_
	y comp of vector from optical flow position 1 to the centroid
scalar_t	delta_12_x_
	x comp of vector from optical flow position 1 to position 2
scalar_t	delta_12_y_
	y comp vector from optical flow position 1 to position 2
scalar_t	mag_ref_
	magnitude of the vector between positions 1 and 2 in the reference frame
scalar_t	ref_cx_
	reference centroid x
scalar_t	ref_cy_
	reference centroid y
scalar_t	initial_u_
	initial displacement for this sequence
scalar_t	initial_v_
	initial displacement for this sequence
scalar_t	initial_t_
	initial rotation for this sequence
int_t	ids_ [2]
	pixel ids of the optical flow points
Protected Attributes inherited from DICe::Initializer
Schema *	schema_
	pointer to the schema that created this initializer, used for field access

Detailed Description

an initializer that uses optical flow to predict the next location of the subset (Lucas-Kanade algorithm). This initializer is only intended for the TRACKING_ROUTINE correlation routine

Initially, two pixels are selected as the locations for doing optical flow based the gradient values for each pixel. If one of the pixels become obstructed the locations need to be reset. The word reference in this class is used to denote the first frame after the positions have been reset. The displacements and rotations are cumulative starting with the reference frame. If the positions need to be reset due to obstructions, the optical flow routine restarts from the new location, which is now the reference frame.

Constructor & Destructor Documentation

Optical_Flow_Initializer()

DICe::Optical_Flow_Initializer::Optical_Flow_Initializer	(	Schema *	schema,
		Teuchos::RCP< Subset >	subset
	)

constructor

Parameters

schema	the parent schema
subset	pointer to the subset for this initializer

Member Function Documentation

best_optical_flow_point()

int_t DICe::Optical_Flow_Initializer::best_optical_flow_point	(	scalar_t &	best_grad,
		Teuchos::ArrayRCP< int_t > &	def_x,
		Teuchos::ArrayRCP< int_t > &	def_y,
		Teuchos::ArrayRCP< scalar_t > &	gx,
		Teuchos::ArrayRCP< scalar_t > &	gy,
		std::set< std::pair< int_t, int_t > > &	subset_pixels,
		Teuchos::RCP< std::vector< int_t > >	existing_points = Teuchos::null,
		const bool	allow_close_points = false
	)

returns the pixel id of the best location for optical flow

Parameters

best_grad	[out] the gradient metric at the best location for an optical flow point
existing_points	the set of global ids for points that are already OF points
def_x	array of the deformed x coordinates for the pixels
def_y	array of the deformed y coordinates for the pixels
gx	the array of x gradient values from the deformed location
gy	the array of y gradient values from the deformed location
subset_pixels	the current pixels occupied by the subset in the deformed configuration
existing_points	vector of the existing optical flow points
allow_close_points	enable the point locations to be near each other (usually leads to more error)

is_near_deactivated()

bool DICe::Optical_Flow_Initializer::is_near_deactivated

(

const int_t

pixel_id

)

returns true if the point is deactivated or neighbors a deactivated pixel

Parameters

pixel_id

the index of the pixel to test

neighbor()

size_t DICe::Optical_Flow_Initializer::neighbor ( const int_t  pixel_id, const int_t  neighbor_index  ) const

inline

returns the id of the neighbor pixel

Parameters

pixel_id	the id of the pixel to gather a neighbor for
neighbor_index	the index of the neighbor

set_locations()

Status_Flag DICe::Optical_Flow_Initializer::set_locations

(

const int_t

subset_gid

)

determine the best locations in the subset to do optical flow based on the gradients

Parameters

subset_gid

the global id of the subset using this initializer