imageUtil.cpp

   1 #include "imageUtil.h"
   2
   3 #include <QImage>
   4
   5 using namespace std;
   6 namespace Color {
   7         const Real
   8                 YCbCrCoeffs[][4]= {
   9                 { 0.299,     0.587,     0.114,    0   },
  10                 {-0.168736, -0.331264,  0.5,      0.5 },
  11                 { 0.5,      -0.418688, -0.081312, 0.5 },
  12
  13                 { 1,         1,         1,        0   },
  14                 { 0,        -0.34414,   1.772,   -0.5 },
  15                 { 1.402,    -0.71414,   0,       -0.5 }
  16             },
  17             RGBCoeffs[][4]= {
  18                 {1,0,0,0}, {0,1,0,0}, {0,0,1,0},
  19                 {1,0,0,0}, {0,1,0,0}, {0,0,1,0}
  20             };
  21
  22         vector<Real> getPSNR(const QImage &a,const QImage &b) {
  23                 int width= a.width(), height= a.height();
  24                 int x, y;
  25                 QRgb *line1, *line2;
  26                 long sum, sumR, sumG, sumB;
  27                 sum= sumR= sumG= sumB= 0;
  28                 for (y=0; y<height; ++y) { // \todo using walkers instead?
  29                         line1= (QRgb*)a.scanLine(y);
  30                         line2= (QRgb*)b.scanLine(y);
  31                         for (x=0; x<width; ++x) {
  32                                 sum+= sqr( getGray(line1[x]) - getGray(line2[x]) );
  33                                 sumR+= sqr( qRed(line1[x]) - qRed(line2[x]) );
  34                                 sumG+= sqr( qGreen(line1[x]) - qGreen(line2[x]) );
  35                                 sumB+= sqr( qBlue(line1[x]) - qBlue(line2[x]) );
  36                         }
  37                 }
  38                 vector<Real> result(4);
  39                 result[0]= sumR;
  40                 result[1]= sumG;
  41                 result[2]= sumB;
  42                 result[3]= sum;
  43                 Real mul= Real(width*height) * Real(sqr(255));
  44                 for (vector<Real>::iterator it=result.begin(); it!=result.end(); ++it)
  45                         *it= Real(10) * log10(mul / *it);
  46                 return result;
  47         }
  48
  49 } // Color namespace