Construct thin plate spline to map 2D to 2D. More...

#include <mbl_thin_plate_spline_2d.h>

Public Member Functions
	mbl_thin_plate_spline_2d ()
	Dflt ctor.
virtual	~mbl_thin_plate_spline_2d ()
	Destructor.
void	build (const vcl_vector< vgl_point_2d< double > > &source_pts, const vcl_vector< vgl_point_2d< double > > &dest_pts, bool compute_the_energy=false)
	Sets up internal transformation to map source_pts onto dest_pts.
void	set_source_pts (const vcl_vector< vgl_point_2d< double > > &source_pts)
	Define source point positions.
const vcl_vector< vgl_point_2d < double > > &	src_pts () const
	Return current source points.
void	build (const vcl_vector< vgl_point_2d< double > > &dest_pts)
	Sets up internal transformation to map source_pts onto dest_pts.
vgl_point_2d< double >	operator() (double x, double y) const
	Return transformed version of (x,y).
vgl_point_2d< double >	operator() (const vgl_point_2d< double > &p) const
	Return transformed version of (x,y).
double	bendingEnergyX () const
	Bending energy of X component (zero for pure affine).
double	bendingEnergyY () const
	Bending energy of X component (zero for pure affine).
void	set_pure_affine (bool val)
	If this parameter is set to true, then only global affine part of the currently computed transformation is used.
short	version_no () const
	Version number for I/O.
void	print_summary (vcl_ostream &os) const
	Print class to os.
void	b_write (vsl_b_ostream &bfs) const
	Save class to binary file stream.
void	b_read (vsl_b_istream &bfs)
	Load class from binary file stream.
bool	operator== (const mbl_thin_plate_spline_2d &tps) const
	Comparison operator.
Private Member Functions
void	build_pure_affine (const vcl_vector< vgl_point_2d< double > > &source_pts, const vcl_vector< vgl_point_2d< double > > &dest_pts)
	Build from small number of points.
void	set_params (const vnl_vector< double > &W1, const vnl_vector< double > &W2)
	Set parameters from vectors.
void	set_up_rhs (vnl_vector< double > &Bx, vnl_vector< double > &By, const vcl_vector< vgl_point_2d< double > > &dest_pts)
void	compute_energy (vnl_vector< double > &W1, vnl_vector< double > &W2, const vnl_matrix< double > &L)
	Compute spline-bending energy.
Private Attributes
vnl_vector< double >	Wx_
vnl_vector< double >	Wy_
double	Ax0_
double	AxX_
double	AxY_
double	Ay0_
double	AyX_
double	AyY_
double	energy_x_
double	energy_y_
bool	return_pure_affine_
vcl_vector< vgl_point_2d < double > >	src_pts_
vnl_matrix< double >	L_inv_
	Used to estimate weights in set_source_points().

Detailed Description

Construct thin plate spline to map 2D to 2D.

I.e. does some mapping (x',y') = f(x,y). (See Booksteins work, e.g. IPMI 1993) The warp is `guided' by a set of landmarks p(0) .. p(n-1) in the source plane which are to be mapped to a (possibly deformed) set q(0)..q(n-1) in the destination. Thus the mapping is constrained so that f(p(i)) = q(i) for i = 0..n-1. The points are given to the build() function to set up the object.

If one wishes to map a set of source points to multiple target points, use set_source_pts(src_pts); then build(target_pts); for each target set.

   vcl_vector<vgl_point_2d<double> > src_pts(n_points),dest_pts(n_points);
  
   Fill src_pts and dest_pts
   .....
  
   Construct spline object
   mbl_thin_plate_spline_2d tps;
   tps.build(src_pts,dest_pts);
  
   // Apply to point p:
   vgl_point_3d<double> p(1,2);
  
   vgl_point_2d<double> new_p = tps(p);

Definition at line 43 of file mbl_thin_plate_spline_2d.h.

Constructor & Destructor Documentation

mbl_thin_plate_spline_2d::mbl_thin_plate_spline_2d ( )

Dflt ctor.

Definition at line 27 of file mbl_thin_plate_spline_2d.cxx.

mbl_thin_plate_spline_2d::~mbl_thin_plate_spline_2d ( ) [virtual]

Destructor.

Definition at line 38 of file mbl_thin_plate_spline_2d.cxx.

Member Function Documentation

void mbl_thin_plate_spline_2d::b_read ( vsl_b_istream & bfs )

Load class from binary file stream.

Definition at line 511 of file mbl_thin_plate_spline_2d.cxx.

void mbl_thin_plate_spline_2d::b_write ( vsl_b_ostream & bfs ) const

Save class to binary file stream.

Definition at line 495 of file mbl_thin_plate_spline_2d.cxx.

double mbl_thin_plate_spline_2d::bendingEnergyX ( ) const [inline]

Bending energy of X component (zero for pure affine).

A measure of total amount of non-linear deformation

Definition at line 109 of file mbl_thin_plate_spline_2d.h.

double mbl_thin_plate_spline_2d::bendingEnergyY ( ) const [inline]

Bending energy of X component (zero for pure affine).

A measure of total amount of non-linear deformation

Definition at line 113 of file mbl_thin_plate_spline_2d.h.

void mbl_thin_plate_spline_2d::build	(	const vcl_vector< vgl_point_2d< double > > &	source_pts,
		const vcl_vector< vgl_point_2d< double > > &	dest_pts,
		bool	compute_the_energy = `false`
	)

Sets up internal transformation to map source_pts onto dest_pts.

Definition at line 339 of file mbl_thin_plate_spline_2d.cxx.

void mbl_thin_plate_spline_2d::build ( const vcl_vector< vgl_point_2d< double > > & dest_pts )

Sets up internal transformation to map source_pts onto dest_pts.

Definition at line 411 of file mbl_thin_plate_spline_2d.cxx.

void mbl_thin_plate_spline_2d::build_pure_affine	(	const vcl_vector< vgl_point_2d< double > > &	source_pts,
		const vcl_vector< vgl_point_2d< double > > &	dest_pts
	)		`[private]`

Build from small number of points.

Definition at line 127 of file mbl_thin_plate_spline_2d.cxx.

void mbl_thin_plate_spline_2d::compute_energy	(	vnl_vector< double > &	W1,
		vnl_vector< double > &	W2,
		const vnl_matrix< double > &	L
	)		`[private]`

Compute spline-bending energy.

Definition at line 290 of file mbl_thin_plate_spline_2d.cxx.

vgl_point_2d< double > mbl_thin_plate_spline_2d::operator()	(	double	x,
		double	y
	)		const

Return transformed version of (x,y).

Definition at line 440 of file mbl_thin_plate_spline_2d.cxx.

vgl_point_2d<double> mbl_thin_plate_spline_2d::operator() ( const vgl_point_2d< double > & p ) const [inline]

Return transformed version of (x,y).

Definition at line 104 of file mbl_thin_plate_spline_2d.h.

bool mbl_thin_plate_spline_2d::operator== ( const mbl_thin_plate_spline_2d & tps ) const

Comparison operator.

Definition at line 537 of file mbl_thin_plate_spline_2d.cxx.

void mbl_thin_plate_spline_2d::print_summary ( vcl_ostream & os ) const

Print class to os.

Definition at line 479 of file mbl_thin_plate_spline_2d.cxx.

void mbl_thin_plate_spline_2d::set_params	(	const vnl_vector< double > &	W1,
		const vnl_vector< double > &	W2
	)		`[private]`

Set parameters from vectors.

Definition at line 262 of file mbl_thin_plate_spline_2d.cxx.

void mbl_thin_plate_spline_2d::set_pure_affine ( bool val ) [inline]

If this parameter is set to true, then only global affine part of the currently computed transformation is used.

Definition at line 118 of file mbl_thin_plate_spline_2d.h.

void mbl_thin_plate_spline_2d::set_source_pts ( const vcl_vector< vgl_point_2d< double > > & source_pts )

Define source point positions.

Performs pre-computations so that build(dest_points) can be called multiple times efficiently

Definition at line 387 of file mbl_thin_plate_spline_2d.cxx.

void mbl_thin_plate_spline_2d::set_up_rhs	(	vnl_vector< double > &	Bx,
		vnl_vector< double > &	By,
		const vcl_vector< vgl_point_2d< double > > &	dest_pts
	)		`[private]`