/*-------------------------------------------------------------------  File        : image_registration.cpp  Description : Compute a motion field between two images,                 with a multiscale and variational algorithm  Copyright  : David Tschumperle - http://www.greyc.ensicaen.fr/~dtschump/    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;// The undef below is necessary when using a non-standard compiler.#ifdef cimg_use_visualcpp6#define std#endif// 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 = CImgList<unsigned char>(src,dest,src).get_append('x'), warp(src);  float t=0;  for (unsigned int iter=0; !disp || (!disp->is_closed && disp->key!=cimg::keyQ); iter++) {    if (morph) cimg_forXYV(warp,x,y,k) {      const float dx = u(x,y,0), dy = u(x,y,1),         I1 = (float)src.linear_pix2d(x-t*dx, y-t*dy, k),        I2 = (float)dest.linear_pix2d(x+(1-t)*dx,y+(1-t)*dy,k);      warp(x,y,k) = (unsigned char)((1-t)*I1 + t*I2);    } else cimg_forXYV(warp,x,y,k) {      const float dx = u(x,y,0), dy = u(x,y,1), I1 = (float)src.linear_pix2d(x-t*dx, y-t*dy, 0,k);      warp(x,y,k) = (unsigned char)I1;    }    if (disp) visu.draw_image(warp,2*src.dimx(),0).display(disp->resize().wait(30));    if (filename && *filename && (imode || (int)iter<nb)) {      std::fprintf(stderr,"\r  > frame %d           ",iter);      warp.save(filename,iter);     }    t+=1.0f/nb;    if (t<0) { t=0; nb=-nb; }    if (t>1) { t=1; nb=-nb; if (filename && *filename) std::exit(0); }  }}// get_warp() : Return the image src warped by the motion field u.//------------template<typename T> CImg<T> getwarp(const CImg<T>& src, const CImg<>& u) {  CImg<T> warp(src);  cimg_forXY(warp,x,y) warp(x,y) = (T)src.linear_pix2d(x - u(x,y,0), y - u(x,y,1));  return warp;}// optmonoflow() : Register images for one scale ( semi-implicite PDE scheme ) between I2->I1//---------------CImg<> optmonoflow(const CImg<>& I1,const CImg<>& I2,const CImg<>& u0,                    const float smooth, const float precision,CImgDisplay *disp) {  CImg<> u = u0.get_resize(I1.dimx(),I1.dimy(),1,2,3),dI(u);  CImg_3x3(I,float);  float dt=2,E=1e20f;  // compute first derivatives of I2  cimg_for3x3(I2,x,y,0,0,I) {    dI(x,y,0) = 0.5f*(Inc-Ipc);    dI(x,y,1) = 0.5f*(Icn-Icp);  }  // Main PDE iteration  for (unsigned int iter=0; iter<100000; iter++) {    std::fprintf(stderr,"\r- Iteration %d - E = %g",iter,E); std::fflush(stderr);    const float Eold = E;    E = 0;    cimg_for3XY(u,x,y) {      const float         X = x + u(x,y,0),        Y = y + u(x,y,1),        deltaI = (float)(I2.linear_pix2d(X,Y) - I1(x,y));      float tmpf = 0;      cimg_forV(u,k) {        const float          ux  = 0.5f*(u(_nx,y,k)-u(_px,y,k)),          uy  = 0.5f*(u(x,_ny,k)-u(x,_py,k));        u(x,y,k) = (float)( u(x,y,k) +                            dt*(                                -deltaI*dI.linear_pix2d(X,Y,k) +                                smooth* ( u(_nx,y,k) + u(_px,y,k) + u(x,_ny,k) + u(x,_py,k) )                                )                            )/(1+4*smooth*dt);        tmpf += ux*ux + uy*uy;      }      E += deltaI*deltaI + smooth * tmpf;    }    if (cimg::abs(Eold-E)<precision) break;    if (Eold<E) dt*=0.5;    if (disp) disp->resize();    if (disp && disp->is_closed) std::exit(0);    if (disp && !(iter%300)) {      const unsigned char white = 255;      CImg<unsigned char> tmp = getwarp(I1,u).normalize(0,200);      tmp.resize(disp->dimx(),disp->dimy()).draw_quiver(u,&white,15,-14,0,0.7f).display(*disp);    }  }  return u;}// optflow() : multiscale version of the image registration algorithm//-----------CImg<> optflow(const CImg<>& xsrc,const CImg<>& xdest,               const float smooth,const float precision,const unsigned int pnb_scale,CImgDisplay *disp=NULL) {  const CImg<>    src  = xsrc.get_norm_pointwise(1).resize(xdest.dimx(),xdest.dimy(),1,1,3).normalize(0,1),    dest = xdest.get_norm_pointwise(1).resize(xdest.dimx(),xdest.dimy(),1,1,3).normalize(0,1);  CImg<> u = CImg<>(src.dimx(),src.dimy(),1,2).fill(0);  const unsigned int nb_scale = pnb_scale>0?pnb_scale:(unsigned int)(2*std::log((double)(cimg::max(src.dimx(),src.dimy()))));  for (int scale=nb_scale-1; scale>=0; scale--) {    const CImg<> I1 = src.get_resize((int)(src.dimx()/std::pow(1.5,scale)), (int)(src.dimy()/std::pow(1.5,scale)) ,1,1,3);    const CImg<> I2 = dest.get_resize((int)(src.dimx()/std::pow(1.5,scale)), (int)(src.dimy()/std::pow(1.5,scale)) ,1,1,3);    std::fprintf(stderr," * Scale %d\n",scale);    u*=1.5;    u = optmonoflow(I1,I2,u,smooth,(float)(precision/std::pow(2.25,1+scale)),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","img/sh0r.pgm","Input Image 1 (Destination)"),    *name_i2   = cimg_option("-i2","img/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    smooth    = cimg_option("-s",0.1f,"Flow Smoothness"),    precision = cimg_option("-p",0.9f,"Convergence precision");  const unsigned int    nb        = cimg_option("-n",40,"Number of warped frames"),    nbscale   = 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_histogram():src.get_blur(0.5f),    dest_blur = normalize?dest.get_blur(0.5f).equalize_histogram():dest.get_blur(0.5f);    CImgDisplay *disp = NULL;  if (dispflag) {    unsigned int w = src.dimx(), h = src.dimy();    const unsigned int dmin = cimg::min(w,h), minsiz = 512;    if (dmin<minsiz) { w=w*minsiz/dmin; h=h*minsiz/dmin; }    const unsigned int dmax = cimg::max(w,h), maxsiz = 1024;    if (dmax>maxsiz) { w=w*maxsiz/dmax; h=h*maxsiz/dmax; }    disp = new CImgDisplay(w,h,"Estimated Motion",0,3);  }  // Run Motion estimation algorithm  std::fprintf(stderr," - Compute optical flow.\n");  const CImg<> u = optflow(src_blur,dest_blur,smooth,precision,nbscale,disp);  if (name_o) u.save(name_o);  u.print("Computed flow");    // Do morphing animation  std::fprintf(stderr," - Create warped animation.\n");  CImgDisplay *disp2 = NULL;  if (dispflag) {    unsigned int w = src.dimx(), h = src.dimy();    const unsigned int dmin = cimg::min(w,h), minsiz = 100;    if (dmin<minsiz) { w=w*minsiz/dmin; h=h*minsiz/dmin; }    const unsigned int dmax = cimg::max(w,h), maxsiz = 1024/3;    if (dmax>maxsiz) { w=w*maxsiz/dmax; h=h*maxsiz/dmax; }    disp2 = new CImgDisplay(3*w,h,"Source/Destination images and Motion animation",0,19);  }    animate_warp(src.get_normalize(0,255),dest.get_normalize(0,255),u,morph,imode,name_seq,nb,disp2);    if (disp) delete disp;  if (disp2) delete disp2;  std::exit(0);  return 0;}