# tpsGetWarp

## PURPOSE

Given two sets of corresponding points, calculates warp between them.

## SYNOPSIS

function [warp,L,LnInv,bendE] = tpsGetWarp( lambda, xsS, ysS, xsD, ysD )

## DESCRIPTION

     Given two sets of corresponding points, calculates warp between them.

     Uses booksteins PAMI89 method.  Can then apply warp to a new set of
     points (tpsInterpolate), or even an image (tpsInterpolateIm).
      "Principal Warps: Thin-Plate Splines and the Decomposition of
      Deformations".  Bookstein.  PAMI 1989.

     USAGE
      [warp,L,LnInv,bendE] = tpsGetWarp( lambda, xsS, ysS, xsD, ysD )

     INPUTS
      lambda      - rigidity of warp (inf means warp becomes affine)
      xsS, ysS    - [1xn] correspondence points from source image
      xsD, ysD    - [1xn] correspondence points from destination image

     OUTPUTS
      warp        - bookstein warping parameters
      L, LnInv    - see bookstein
      bendE       - bending energy

     EXAMPLE - 1
      xsS=[0 -1 0 1];  ysS=[1 0 -1 0];  xsD=xsS;  ysD=[3/4 1/4 -5/4 1/4];
      warp = tpsGetWarp( 0, xsS, ysS, xsD, ysD );
      [gxs, gys] = meshgrid(-1.25:.25:1.25,-1.25:.25:1.25);
      tpsInterpolate( warp, gxs, gys, 1 );

     EXAMPLE - 2
      xsS = [3.6929 6.5827 6.7756 4.8189 5.6969];
      ysS = [10.3819 8.8386 12.0866 11.2047 10.0748];
      xsD = [3.9724 6.6969 6.5394 5.4016 5.7756];
      ysD = [6.5354 4.1181 7.2362 6.4528 5.1142];
      warp = tpsGetWarp( 0, xsS, ysS, xsD, ysD );
      [gxs, gys] = meshgrid(3.5:.25:7, 8.5:.25: 12.5);
      tpsInterpolate( warp, gxs, gys, 1 );

     See also TPSINTERPOLATE, TPSINTERPOLATEIM, TPSRANDOM

     Piotr's Image&Video Toolbox      Version 2.0
     Copyright 2008 Piotr Dollar.  [pdollar-at-caltech.edu]
     Please email me if you find bugs, or have suggestions or questions!
     Licensed under the Lesser GPL [see external/lgpl.txt]

## CROSS-REFERENCE INFORMATION

This function calls:

This function is called by: