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/*
#
# File : image_registration2d.cpp
# ( C++ source file )
#
# Description : Compute a motion field between two images,
# with a multiscale and variational algorithm.
# This file is a part of the CImg Library project.
# ( http://cimg.eu )
#
# Copyright : David Tschumperlé
# ( http://tschumperle.users.greyc.fr/ )
#
# License : CeCILL v2.0
# ( http://www.cecill.info/licences/Licence_CeCILL_V2-en.html )
#
# This software is governed by the CeCILL license under French law and
# abiding by the rules of distribution of free software. You can use,
# modify and/ or redistribute the software under the terms of the CeCILL
# license as circulated by CEA, CNRS and INRIA at the following URL
# "http://www.cecill.info".
#
# As a counterpart to the access to the source code and rights to copy,
# modify and redistribute granted by the license, users are provided only
# with a limited warranty and the software's author, the holder of the
# economic rights, and the successive licensors have only limited
# liability.
#
# In this respect, the user's attention is drawn to the risks associated
# with loading, using, modifying and/or developing or reproducing the
# software by the user in light of its specific status of free software,
# that may mean that it is complicated to manipulate, and that also
# therefore means that it is reserved for developers and experienced
# professionals having in-depth computer knowledge. Users are therefore
# encouraged to load and test the software's suitability as regards their
# requirements in conditions enabling the security of their systems and/or
# data to be ensured and, more generally, to use and operate it in the
# same conditions as regards security.
#
# The fact that you are presently reading this means that you have had
# knowledge of the CeCILL license and that you accept its terms.
#
*/
#include "CImg.h"
using namespace cimg_library;
#ifndef cimg_imagepath
#define cimg_imagepath "img/"
#endif
#undef min
#undef max
// animate_warp() : Create warping animation from two images and a motion field
//----------------
void animate_warp(const CImg<unsigned char>& src, const CImg<unsigned char>& dest, const CImg<>& U,
const bool morph, const bool imode, const char *filename,int nb, CImgDisplay& disp) {
CImg<unsigned char> visu = (src,dest,src)>'x', warp(src);
float t = 0;
for (unsigned int iteration = 0; !disp || (!disp.is_closed() && !disp.is_keyQ()); ++iteration) {
if (morph) cimg_forXYC(warp,x,y,k) {
const float dx = U(x,y,0), dy = U(x,y,1),
I1 = (float)src.linear_atXY(x - t*dx, y - t*dy, k),
I2 = (float)dest.linear_atXY(x + (1 - t)*dx,y + (1 - t)*dy,k);
warp(x,y,k) = (unsigned char)((1 - t)*I1 + t*I2);
} else cimg_forXYC(warp,x,y,k) {
const float dx = U(x,y,0), dy = U(x,y,1), I1 = (float)src.linear_atXY(x - t*dx, y - t*dy, 0,k);
warp(x,y,k) = (unsigned char)I1;
}
if (disp) visu.draw_image(2*src.width(),warp).display(disp.resize().wait(30));
if (filename && *filename && (imode || (int)iteration<nb)) {
std::fprintf(stderr,"\r > frame %d ",iteration);
warp.save(filename,iteration);
}
t+=1.0f/nb;
if (t<0) { t = 0; nb = -nb; }
if (t>1) { t = 1; nb = -nb; if (filename && *filename) std::exit(0); }
}
}
// optflow() : multiscale version of the image registration algorithm
//-----------
CImg<> optflow(const CImg<>& source, const CImg<>& target,
const float smoothness, const float precision, const unsigned int nb_scales, CImgDisplay& disp) {
const unsigned int iteration_max = 100000;
const float _precision = (float)std::pow(10.0,-(double)precision);
const CImg<>
src = source.get_resize(target,3).normalize(0,1),
dest = target.get_normalize(0,1);
CImg<> U;
const unsigned int _nb_scales = nb_scales>0?nb_scales:
(unsigned int)(2*std::log((double)(std::max(src.width(),src.height()))));
for (int scale = _nb_scales - 1; scale>=0; --scale) {
const float factor = (float)std::pow(1.5,(double)scale);
const unsigned int
_sw = (unsigned int)(src.width()/factor), sw = _sw?_sw:1,
_sh = (unsigned int)(src.height()/factor), sh = _sh?_sh:1;
const CImg<>
I1 = src.get_resize(sw,sh,1,-100,2),
I2 = dest.get_resize(I1,2);
std::fprintf(stderr," * Scale %d\n",scale);
if (U) (U*=1.5f).resize(I2.width(),I2.height(),1,-100,3);
else U.assign(I2.width(),I2.height(),1,2,0);
float dt = 2, energy = cimg::type<float>::max();
const CImgList<> dI = I2.get_gradient();
for (unsigned int iteration = 0; iteration<iteration_max; ++iteration) {
std::fprintf(stderr,"\r- Iteration %d - E = %g",iteration,energy); std::fflush(stderr);
float _energy = 0;
cimg_for3XY(U,x,y) {
const float
X = x + U(x,y,0),
Y = y + U(x,y,1);
float deltaI = 0;
cimg_forC(I2,c) deltaI+=(float)(I1(x,y,c) - I2.linear_atXY(X,Y,c));
float _energy_regul = 0;
cimg_forC(U,c) {
const float
Ux = 0.5f*(U(_n1x,y,c) - U(_p1x,y,c)),
Uy = 0.5f*(U(x,_n1y,c) - U(x,_p1y,c)),
Uxx = U(_n1x,y,c) + U(_p1x,y,c),
Uyy = U(x,_n1y,c) + U(x,_p1y,c);
U(x,y,c) = (float)( U(x,y,c) + dt*(deltaI*dI[c].linear_atXY(X,Y) +
smoothness* ( Uxx + Uyy )))/(1 + 4*smoothness*dt);
_energy_regul+=Ux*Ux + Uy*Uy;
}
_energy+=deltaI*deltaI + smoothness*_energy_regul;
}
const float d_energy = (_energy - energy)/(sw*sh);
if (d_energy<=0 && -d_energy<_precision) break;
if (d_energy>0) dt*=0.5f;
energy = _energy;
if (disp) disp.resize();
if (disp && disp.is_closed()) std::exit(0);
if (disp && !(iteration%300)) {
const unsigned char white[] = { 255,255,255 };
CImg<unsigned char> tmp = I1.get_warp(U,true,true,1).normalize(0,200);
tmp.resize(disp.width(),disp.height()).draw_quiver(U,white,0.7f,15,-14,true).display(disp);
}
}
std::fprintf(stderr,"\n");
}
return U;
}
/*------------------------
Main function
------------------------*/
int main(int argc,char **argv) {
// Read command line parameters
cimg_usage("Compute an optical flow between two 2D images, and create a warped animation");
const char
*name_i1 = cimg_option("-i",cimg_imagepath "sh0r.pgm","Input Image 1 (Destination)"),
*name_i2 = cimg_option("-i2",cimg_imagepath "sh1r.pgm","Input Image 2 (Source)"),
*name_o = cimg_option("-o",(const char*)NULL,"Output 2D flow (inrimage)"),
*name_seq = cimg_option("-o2",(const char*)NULL,"Output Warping Sequence");
const float
smoothness = cimg_option("-s",0.1f,"Flow Smoothness"),
precision = cimg_option("-p",6.0f,"Convergence precision");
const unsigned int
nb = cimg_option("-n",40,"Number of warped frames"),
nb_scales = cimg_option("-scale",0,"Number of scales (0=auto)");
const bool
normalize = cimg_option("-equalize",true,"Histogram normalization of the images"),
morph = cimg_option("-m",true,"Morphing mode"),
imode = cimg_option("-c",true,"Complete interpolation (or last frame is missing)"),
dispflag = !cimg_option("-novisu",false,"Visualization");
// Init images and display
std::fprintf(stderr," - Init images.\n");
const CImg<>
src(name_i1),
dest(CImg<>(name_i2).resize(src,3)),
src_blur = normalize?src.get_blur(0.5f).equalize(256):src.get_blur(0.5f),
dest_blur = normalize?dest.get_blur(0.5f).equalize(256):dest.get_blur(0.5f);
CImgDisplay disp;
if (dispflag) {
unsigned int w = src.width(), h = src.height();
const unsigned int dmin = std::min(w,h), minsiz = 512;
if (dmin<minsiz) { w=w*minsiz/dmin; h=h*minsiz/dmin; }
const unsigned int dmax = std::max(w,h), maxsiz = 1024;
if (dmax>maxsiz) { w=w*maxsiz/dmax; h=h*maxsiz/dmax; }
disp.assign(w,h,"Estimated Motion",0);
}
// Run Motion estimation algorithm
std::fprintf(stderr," - Compute optical flow.\n");
const CImg<> U = optflow(src_blur,dest_blur,smoothness,precision,nb_scales,disp);
if (name_o) U.save(name_o);
U.print("Computed flow");
// Do morphing animation
std::fprintf(stderr," - Create warped animation.\n");
CImgDisplay disp2;
if (dispflag) {
unsigned int w = src.width(), h = src.height();
const unsigned int dmin = std::min(w,h), minsiz = 100;
if (dmin<minsiz) { w = w*minsiz/dmin; h=h*minsiz/dmin; }
const unsigned int dmax = std::max(w,h), maxsiz = 1024/3;
if (dmax>maxsiz) { w = w*maxsiz/dmax; h=h*maxsiz/dmax; }
disp2.assign(3*w,h,"Source/Destination images and Motion animation",0);
}
animate_warp(src.get_normalize(0,255),dest.get_normalize(0,255),U,morph,imode,name_seq,nb,disp2);
std::exit(0);
return 0;
}
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