root/modules/photo/src/contrast_preserve.cpp

DEFINITIONS

1. decolor

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#include "precomp.hpp"
#include "opencv2/photo.hpp"
#include "math.h"
#include <vector>
#include <limits>
#include "contrast_preserve.hpp"

using namespace std;
using namespace cv;

void cv::decolor(InputArray _src, OutputArray _dst, OutputArray _color_boost)
{
    Mat I = _src.getMat();
    _dst.create(I.size(), CV_8UC1);
    Mat dst = _dst.getMat();

    _color_boost.create(I.size(), CV_8UC3);
    Mat color_boost = _color_boost.getMat();

    CV_Assert(!I.empty() && (I.channels()==3));

    // Parameter Setting
    int maxIter = 15;
    int iterCount = 0;
    double tol = .0001;
    double E = 0;
    double pre_E = std::numeric_limits<double>::infinity();

    Decolor obj;

    Mat img;

    img = Mat(I.size(),CV_32FC3);
    I.convertTo(img,CV_32FC3,1.0/255.0);

    // Initialization
    obj.init();

    vector <double> Cg;
    vector < vector <double> > polyGrad;
    vector < vector < int > > comb;

    vector <double> alf;

    obj.grad_system(img,polyGrad,Cg,comb);
    obj.weak_order(img,alf);

    // Solver
    Mat Mt = Mat((int)polyGrad.size(),(int)polyGrad[0].size(), CV_32FC1);
    obj.wei_update_matrix(polyGrad,Cg,Mt);

    vector <double> wei;
    obj.wei_inti(comb,wei);

    //////////////////////////////// main loop starting ////////////////////////////////////////

    while(sqrt(pow(E-pre_E,2)) > tol)
    {
        iterCount +=1;
        pre_E = E;

        vector <double> G_pos;
        vector <double> G_neg;

        vector <double> temp;
        vector <double> temp1;

        double val = 0.0;
        for(unsigned int i=0;i< polyGrad[0].size();i++)
        {
            val = 0.0;
            for(unsigned int j =0;j<polyGrad.size();j++)
                val = val + (polyGrad[j][i] * wei[j]);
            temp.push_back(val - Cg[i]);
            temp1.push_back(val + Cg[i]);
        }

        double pos = 0.0;
        double neg = 0.0;
        for(unsigned int i =0;i<alf.size();i++)
        {
            pos = ((1 + alf[i])/2) * exp((-1.0 * 0.5 * pow(temp[i],2))/pow(obj.sigma,2));
            neg = ((1 - alf[i])/2) * exp((-1.0 * 0.5 * pow(temp1[i],2))/pow(obj.sigma,2));
            G_pos.push_back(pos);
            G_neg.push_back(neg);
        }

        vector <double> EXPsum;
        vector <double> EXPterm;

        for(unsigned int i = 0;i<G_pos.size();i++)
            EXPsum.push_back(G_pos[i]+G_neg[i]);

        vector <double> temp2;

        for(unsigned int i=0;i<EXPsum.size();i++)
        {
            if(EXPsum[i] == 0)
                temp2.push_back(1.0);
            else
                temp2.push_back(0.0);
        }

        for(unsigned int i =0; i < G_pos.size();i++)
            EXPterm.push_back((G_pos[i] - G_neg[i])/(EXPsum[i] + temp2[i]));

        double val1 = 0.0;
        vector <double> wei1;

        for(unsigned int i=0;i< polyGrad.size();i++)
        {
            val1 = 0.0;
            for(unsigned int j =0;j<polyGrad[0].size();j++)
            {
                val1 = val1 + (Mt.at<float>(i,j) * EXPterm[j]);
            }
            wei1.push_back(val1);
        }

        for(unsigned int i =0;i<wei.size();i++)
            wei[i] = wei1[i];

        E = obj.energyCalcu(Cg,polyGrad,wei);

        if(iterCount > maxIter)
            break;

        G_pos.clear();
        G_neg.clear();
        temp.clear();
        temp1.clear();
        EXPsum.clear();
        EXPterm.clear();
        temp2.clear();
        wei1.clear();
    }

    Mat Gray = Mat::zeros(img.size(),CV_32FC1);
    obj.grayImContruct(wei, img, Gray);

    Gray.convertTo(dst,CV_8UC1,255);

    ///////////////////////////////////       Contrast Boosting   /////////////////////////////////

    Mat lab = Mat(img.size(),CV_8UC3);
    Mat color = Mat(img.size(),CV_8UC3);

    cvtColor(I,lab,COLOR_BGR2Lab);

    vector <Mat> lab_channel;
    split(lab,lab_channel);

    dst.copyTo(lab_channel[0]);

    merge(lab_channel,lab);

    cvtColor(lab,color_boost,COLOR_Lab2BGR);
}