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tmo_ashikhmin02.cpp

/**
 * @brief Michael Ashikhmin tone mapping operator 2002
 * 
 * This file is a part of Qtpfsgui package, based on pfstmo.
 * ---------------------------------------------------------------------- 
 * Copyright (C) 2003,2004 Grzegorz Krawczyk
 * 
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * ---------------------------------------------------------------------- 
 *
 * @author Akiko Yoshida, <yoshida@mpi-sb.mpg.de>
 * @author Grzegorz Krawczyk, <krawczyk@mpi-sb.mpg.de>
 *
 * $Id: tmo_ashikhmin02.cpp,v 1.6 2004/11/16 13:40:46 yoshida Exp $
 */

#include <iostream>
#include <math.h>
#include <assert.h>

#include "../../Libpfs/array2d.h"
#include "tmo_ashikhmin02.h"
#include "pyramid.h"

#define SMAX 10
#define LDMAX 500.0
#define EPSILON 0.00001

//-------------------------------------------

float calc_LAL_interpolated(GaussianPyramid *myPyramid, int x, int y, int s) {
  float ratio = myPyramid->p[s-1].lambda;  

  float newX = (float)x * ratio;
  float newY = (float)y * ratio;
  int X_int = (int)newX;
  int Y_int = (int)newY;

  float dx, dy, omdx, omdy;
  dx = newX-(float)X_int;
  omdx = 1.0 - dx;
  dy = newY - (float)Y_int;
  omdy = 1.0 - dy;

  int w = myPyramid->p[s-1].GP->getCols();
  int h = myPyramid->p[s-1].GP->getRows();

  float g;
  if(X_int < w-1 && Y_int < h-1) {
    g = omdx * omdy * myPyramid->p[s-1].getPixel(X_int, Y_int)
      +   dx * omdy * myPyramid->p[s-1].getPixel(X_int+1, Y_int)
      + omdx *   dy * myPyramid->p[s-1].getPixel(X_int, Y_int+1)
      +   dx *   dy * myPyramid->p[s-1].getPixel(X_int+1, Y_int+1);
  }
  else if(X_int <  w-1 && Y_int >= h-1) {
    Y_int = h-1;
    g = omdx * myPyramid->p[s-1].getPixel(X_int, Y_int) + dx * myPyramid->p[s-1].getPixel(X_int+1, Y_int);
  }
  else if(X_int >= w-1 && Y_int < h-1) {
    X_int = w-1;
    g = omdy * myPyramid->p[s-1].getPixel(X_int, Y_int) + dy * myPyramid->p[s-1].getPixel(X_int, Y_int+1);
  }
  else
    g = myPyramid->p[s-1].getPixel(w-1, h-1);

  return g;
}

float calc_LAL(GaussianPyramid *myPyramid, int x, int y, int s) {
  float ratio = myPyramid->p[s-1].lambda;  

  float newX = (float)x * ratio;
  float newY = (float)y * ratio;
  int X_int = (int)newX;
  int Y_int = (int)newY;

  if(X_int >= myPyramid->p[s-1].GP->getCols()) X_int = myPyramid->p[s-1].GP->getCols()-1;
  if(Y_int >= myPyramid->p[s-1].GP->getRows()) Y_int = myPyramid->p[s-1].GP->getRows()-1;

  return myPyramid->p[s-1].getPixel(X_int, Y_int);
}

float LAL(GaussianPyramid *myPyramid, int x, int y, float LOCAL_CONTRAST) {
  float g, gg;
  for(int s=1; s<=SMAX; s++) {
    // with interpolation
    g = calc_LAL_interpolated(myPyramid, x, y, s);
    gg = calc_LAL_interpolated(myPyramid, x, y, 2*s);

    // w/o interpolation
    //    g = calc_LAL(myPyramid, x, y, s);
    //     gg = calc_LAL(myPyramid, x, y, 2*s);

    if(fabs((g-gg)/g) >= LOCAL_CONTRAST) 
      return g;
  }
  return g;
}

////////////////////////////////////////////////////////

float C(float lum_val) { // linearly approximated TVI function
  if(lum_val <= 1e-20)
    return 0.0;
  
  if(lum_val < 0.0034) 
    return lum_val/0.0014;
  
  if(lum_val < 1.0) 
    return 2.4483 + log(lum_val/0.0034)/0.4027;
  
  if(lum_val < 7.2444) 
    return 16.5630 + (lum_val-1.0)/0.4027;
  
  return 32.0693 + log(lum_val/7.2444)/0.0556;
}

inline float TM(float lum_val, float maxLum, float minLum) {
  float div = C(maxLum)-C(minLum);
  if(div != 0.0)
    return (LDMAX * (C(lum_val)-C(minLum)) / div);
  else
    return (LDMAX * (C(lum_val)-C(minLum)) / EPSILON);
}

////////////////////////////////////////////////////////

void getMaxMin(pfs::Array2D* lum_map, float& maxLum, float& minLum) {
  maxLum = minLum = 0.0;

  for(int i=0; i<lum_map->getCols() * lum_map->getRows(); i++) {
    maxLum = ((*lum_map)(i) > maxLum) ? (*lum_map)(i) : maxLum;
    minLum = ((*lum_map)(i) < minLum) ? (*lum_map)(i) : minLum;
  }
}

void Normalize(pfs::Array2D* lum_map, int nrows, int ncols) {
  float maxLum, minLum;
  getMaxMin(lum_map, maxLum, minLum);
  float range = maxLum - minLum;
  for(int y=0; y<nrows; y++)
    for(int x=0; x<ncols; x++)
      (*lum_map)(x,y) = ((*lum_map)(x,y)-minLum) / range;
}

////////////////////////////////////////////////////////

int tmo_ashikhmin02(pfs::Array2D* Y, pfs::Array2D* L, float maxLum, float minLum, float /*avLum*/, bool simple_flag, float lc_value, int eq)
{
  assert(Y!=NULL);
  assert(L!=NULL);

  int nrows = Y->getRows();               // image size
  int ncols = Y->getCols();
  assert(nrows==L->getRows() && ncols==L->getCols() );

//   int im_size = nrows * ncols;

  //  maxLum /= avLum;                                      // normalize maximum luminance by average luminance

  // apply ToneMapping function only
  if(simple_flag) {
    for(int y=0; y<nrows; y++)
      for(int x=0; x<ncols; x++)
      {
      (*L)(x,y) = TM((*Y)(x,y), maxLum, minLum);
        
        //!! FIX:
        // to keep output values in range 0.01 - 1
      //        (*L)(x,y) /= 100.0f;
      }
    Normalize(L, nrows, ncols);
    
    return 0;
  }

  // applying the full functions....
  GaussianPyramid *myPyramid = new GaussianPyramid(Y, nrows, ncols);

  // LAL calculation
  pfs::Array2D* la = new pfs::Array2DImpl(ncols, nrows);
  for(int y=0; y<nrows; y++) {
    for(int x=0; x<ncols; x++) {
      (*la)(x,y) = LAL(myPyramid, x, y, lc_value);
      if((*la)(x,y) == 0.0)
      (*la)(x,y) == EPSILON;
    }
  }
  delete(myPyramid);

  // TM function
  pfs::Array2D* tm = new pfs::Array2DImpl(ncols, nrows);
  for(int y=0; y<nrows; y++)
    for(int x=0; x<ncols; x++)
      (*tm)(x,y) = TM((*la)(x,y), maxLum, minLum);

  // final computation for each pixel
  for(int y=0; y<nrows; y++)
    for(int x=0; x<ncols; x++)
    {
      switch (eq) {
      case 2:
      (*L)(x,y) = (*Y)(x,y) * (*tm)(x,y) / (*la)(x,y);
      break;
      case 4:
      (*L)(x,y) =  (*tm)(x,y) + C((*tm)(x,y))/C((*la)(x,y)) * ((*Y)(x,y)-(*la)(x,y));
      break;
      default:
      exit(0);
      }

      //!! FIX:
      // to keep output values in range 0.01 - 1
      //(*L)(x,y) /= 100.0f;
    }

  Normalize(L, nrows, ncols);

  // cleaning
  delete(la);
  delete(tm);

  return 0;  
}


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