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rawTherapee/rtengine/expo_before_b.cc

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C++

////////////////////////////////////////////////////////////////
//
// //exposure correction before interpolation
//
// code dated: December 27, 2010
//
// Expo_before.cc 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 3 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, see <http://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////
// Jacques Desmis <jdesmis@gmail.com>
// use fast-demo(provisional) from Emil Martinec
// inspired from work Guillermo Luijk and Manuel LLorens(Perfectraw)
// Ingo Weyrich (2014-07-07)
// optimized the highlight protection case
// needs 2*width*height*sizeof(float) byte less memory than before
// needs about 60% less processing time than before
//
// This function uses parameters:
// exposure (linear): 2^(-8..0..8): currently 0.5 +3
// preserve (log) : 0..8 : currently 0.1 1
#include "rtengine.h"
#include "rawimagesource.h"
#include "mytime.h"
#include "rt_math.h"
namespace rtengine {
extern const Settings* settings;
void RawImageSource::processRawWhitepoint(float expos, float preser) {
MyTime t1e,t2e;
if (settings->verbose)
t1e.set();
int width=W, height=H;
// exposure correction inspired from G.Luijk
for (int c=0; c<4; c++)
chmax[c] *= expos;
if (fabs(preser)<0.001f) {
// No highlight protection - simple mutiplication
if (ri->getSensorType()!=ST_NONE)
#pragma omp parallel for
for (int row=0;row<height;row++)
for (int col=0;col<width;col++)
rawData[row][col] *= expos;
else
#pragma omp parallel for
for (int row=0;row<height;row++)
for (int col=0;col<width;col++) {
rawData[row][col*3] *= expos;
rawData[row][col*3+1] *= expos;
rawData[row][col*3+2] *= expos;
}
} else {
if (ri->getSensorType()!=ST_NONE) {
// Demosaic to allow calculation of luminosity.
if(ri->getSensorType()==ST_BAYER)
fast_demosaic (0,0,W,H);
else
fast_xtrans_interpolate();
}
// Find maximum to adjust LUTs. New float engines clips only at the very end
float maxValFloat = 0.f;
#pragma omp parallel
{
float maxValFloatThr = 0.f;
if (ri->getSensorType()!=ST_NONE)
#pragma omp for schedule(dynamic,16) nowait
for(int row=0;row<height;row++)
for (int col=0;col<width;col++) {
if (rawData[row][col]>maxValFloatThr)
maxValFloatThr = rawData[row][col];
}
else
#pragma omp for schedule(dynamic,16) nowait
for(int row=0;row<height;row++)
for (int col=0;col<width;col++) {
for (int c=0;c<3;c++) if (rawData[row][col*3+c]>maxValFloatThr)
maxValFloatThr = rawData[row][col*3+c];
}
#pragma omp critical
{
if(maxValFloatThr > maxValFloat)
maxValFloat = maxValFloatThr;
}
}
// Exposure correction with highlight preservation
int maxVal = maxValFloat;
LUTf lut(maxVal+1);
float K;
if(expos>1){
// Positive exposure
K = (float) maxVal / expos*exp(-preser*log(2.0));
for (int j=max(1,(int)K);j<=maxVal;j++)
lut[(int)j]=(((float)maxVal-K*expos)/((float)maxVal-K)*(j-maxVal)+(float) maxVal) / j;
} else {
// Negative exposure
float EV=log(expos)/log(2.0); // Convert exp. linear to EV
K = (float)maxVal * exp(-preser * log(2.0));
for (int j=0;j<=maxVal;j++)
lut[(int)j] = exp(EV*((float)maxVal-j) / ((float)maxVal-K) * log(2.0));
}
if (ri->getSensorType()!=ST_NONE)
#pragma omp parallel for schedule(dynamic,16)
for(int row=0;row<height;row++)
for(int col=0;col<width;col++){
float lumi = 0.299f * red[row][col] + 0.587f * green[row][col] + 0.114f * blue[row][col];
rawData[row][col] *= lumi < K ? expos : lut[lumi];
}
else
#pragma omp parallel for
for(int row=0;row<height;row++)
for(int col=0;col<width;col++){
float lumi = 0.299f * rawData[row][col*3] + 0.587f * rawData[row][col*3+1] + 0.114f * rawData[row][col*3+2];
float fac = lumi < K ? expos : lut[lumi];
for (int c=0;c<3;c++)
rawData[row][col*3+c] *= fac;
}
}
if (settings->verbose) {
t2e.set();
printf("Exposure before %d usec\n", t2e.etime(t1e));
}
}
} //namespace