specification.doc

@@ -1 +1,18 @@
 Plik z Dokumentacja do projektu
+
+
+Zadanie 3
+Histogram to wyliczenie ile razy wystepuje dana wartośc koloru w obrazie.
+Dla każdego kanału : rgb liczona jest liczba wystąpień każdego odcienia od 0 do 255.
+
+Rozciągniecie histogramu :
+najpierw szukamy lewej (min) i prawej (max) krawędzi histogramu, tzn. od jakiej wartości piksela (idąc od lewej i od prawej) zaczynają się pierwsze niezerowe wartości histogramu,
+rozciągamy histogram, czyli każdemu pikselowi na obrazie dajemy nową wartość wg wzoru:
+ Pixel-new [x,y] =  (255/ max-min) * pixel-old[x,y] - min
+ 
+ Wyrównanie 
+ To wyliczenie dystrybuanty czyli histogramu podzielonego przez sume.  Mamy takzwane prawdopobienstwo wystapienia
+ a nastepnie wyliczenie na podstawie wzoru: 
+ Lut[i] = ( ( D[i] - Dmin) / 1 - Dmin ) ) * k-1 , gdzie k to liczba poziomow odcienia czyli 256
+ 
+ 

src/core/histogram.cpp

@@ -24,15 +24,101 @@ Histogram::~Histogram()
 
 void Histogram::generate(QImage* image)
 {
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+
+  qDebug() << Q_FUNC_INFO << " Generating histogram !";
+    for(int i = 0 ; i < image->height(); i++){
+        for(int j = 0 ; j < image->width() ; j++){
+            QColor *clrCurrent = new QColor( image->pixel(i,j) );
+
+             QRgb pixel =   image->pixel(i,j);
+              R->insert(qRed(pixel),R->value(qRed(pixel))+1);
+              G->insert(qGreen(pixel),G->value(qGreen(pixel))+1);
+              B->insert(qBlue(pixel),B->value(qBlue(pixel))+1);
+              L->insert(qAlpha(pixel),L->value(qAlpha(pixel))+1);
+      }
+    }
 }
 
 /** Returns the maximal value of the histogram in the given channel */
 int Histogram::maximumValue(Channel selectedChannel = RGB)
 {
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    int max = 0;
+    if(selectedChannel == LChannel){
+        return getMaxFromQHashHelper(get(selectedChannel));
+    }
 
-    return 0;
+    max = getMaxFromQHashHelper(R);
+
+    if(getMaxFromQHashHelper(G) >  max){
+        max = getMaxFromQHashHelper(G);
+    }
+
+    if(getMaxFromQHashHelper(B) >  max){
+        max = getMaxFromQHashHelper(B);
+    }
+
+    return max;
+}
+
+// Return max or -1  when QHash is empty
+int Histogram::getMaxFromQHashHelper( QHash<int, int>  * channel ){
+    int max = -1;
+
+    QHash<int, int>::const_iterator iterator = channel->begin();
+    while (iterator != channel->end())
+    {
+       if(iterator.value()  > max && iterator.value() != 0 ){
+           max = iterator.value();
+       }
+        ++iterator;
+
+    }
+    return max;
+}
+
+int Histogram::getMaxKey( QHash<int, int>  * channel ){
+    int max = -1;
+
+    QHash<int, int>::const_iterator iterator = channel->begin();
+    while (iterator != channel->end())
+    {
+       if(iterator.key()  > max && iterator.value() != 0){
+           max = iterator.key();
+       }
+        ++iterator;
+
+    }
+    return max;
+}
+
+int Histogram::getMinKey( QHash<int, int>  * channel ){
+    int min = 256;
+
+    QHash<int, int>::const_iterator iterator = channel->begin();
+    while (iterator != channel->end())
+    {
+       if(iterator.key() < min &&  iterator.value() != 0){
+           min = iterator.key();
+       }
+        ++iterator;
+
+    }
+    return min;
+}
+
+//Return min or 256 when qhash is empty
+int Histogram::getMinFromQHashHelper( QHash<int, int>  * channel ){
+    int min = 256;
+
+    QHash<int, int>::const_iterator iterator = channel->begin();
+    while (iterator != channel->end())
+    {
+       if(iterator.value()  < min  && iterator.value() != 0){
+           min = iterator.value();
+       }
+        ++iterator;
+    }
+    return min;
 }
 
 

src/core/histogram.h

@@ -16,10 +16,15 @@ public:
     QHash<int, int>* get(Histogram::Channel);
     QImage           getImage(Histogram::Channel, QBrush);
     int              maximumValue(Channel);
+    int              getMaxFromQHashHelper( QHash<int, int> *);
+    int              getMinFromQHashHelper( QHash<int, int> *);
+    int              getMinKey( QHash<int, int> *);
+    int              getMaxKey( QHash<int, int> *);
 
 private:
     void generate(QImage*); // iterates all parent image pixels and set the Hashes
 
+
     QHash<int, int>* R;
     QHash<int, int>* G;
     QHash<int, int>* B;

src/core/transformations/histogram_equalization.cpp

@@ -16,11 +16,73 @@ PNM* HistogramEqualization::transform()
 {
     int width = image->width();
     int height = image->height();
-
+    int pixelAmounts = width* height;
     PNM* newImage = new PNM(width, height, image->format());
+    double LUTr[256], LUTg[256], LUTb[256],
+         redHist[256], greenHist[256], blueHist[256],
+         distRed[256], distGreen[256], distBlue[256];
 
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    zeros(redHist,greenHist,blueHist);
+    zeros(distRed,distGreen,distBlue);
+    zeros(LUTr,LUTb,LUTg);
 
+    for (int x = 0; x < width; x++){
+      for (int y = 0; y < height; y++)
+      {
+           QRgb pixel = image->pixel(x,y);
+           redHist[qRed(pixel)]++;
+           greenHist[qGreen(pixel)]++;
+           blueHist[qBlue(pixel)]++;
+      }
+    }
+
+  double  sumR = 0;
+  double  sumG = 0;
+  double  sumB = 0;
+
+  for (int i=0; i<256; i++)
+  {
+    sumR += (redHist[i]/pixelAmounts);
+    sumG += (greenHist[i]/pixelAmounts);
+    sumB += (blueHist[i]/pixelAmounts);
+    distRed[i] += sumR;
+    distGreen[i] += sumG;
+    distBlue[i] += sumB;
+  }
+
+  prepareLUTperChannel(distRed, LUTr);
+  prepareLUTperChannel(distGreen, LUTg );
+  prepareLUTperChannel(distBlue, LUTb );
+  for (int i = 0; i< width; i++){
+      for (int j = 0; j< height; j++)
+      {
+          QRgb pixel = image->pixel(i,j);
+          newImage->setPixel(i,j, QColor( LUTr[qRed(pixel)], LUTg[qGreen(pixel)], LUTb[qBlue(pixel)]).rgba() );
+      }
+  }
     return newImage;
 }
 
+void HistogramEqualization::prepareLUTperChannel(double *D, double *LUT)
+{
+    double Dmin = 0;
+    for(int i = 0; i < 256 ; i++){
+        if(D[i+1] > 0){
+            Dmin = D[i+1];
+            break;
+        }
+    }
+
+    for (int i=0; i<256; i++){
+        LUT[i] = ( 255* ((D[i] - Dmin) / (1 - Dmin))) ;
+    }
+}
+
+void HistogramEqualization::zeros(double * r_tab, double * g_tab, double* b_tab){
+    for (int i=0; i<256; i++)
+    {
+      r_tab[i] = 0;
+      g_tab[i] = 0;
+      b_tab[i] = 0;
+    }
+}

src/core/transformations/histogram_equalization.h

@@ -8,8 +8,12 @@ class HistogramEqualization : public Transformation
 public:
     HistogramEqualization(PNM*);
     HistogramEqualization(PNM*, ImageViewer*);
+    QHash<int, int>  prepareDistrubuantPerChannel(QHash <int,int> * , int);
+    void prepareLUTperChannel(double *, double * );
+    void zeros(double *, double * , double * );
 
     virtual PNM* transform();
+    int min(QHash<int, int> *dist);
 };
 
 

src/core/transformations/histogram_stretching.cpp

@@ -14,13 +14,31 @@ HistogramStretching::HistogramStretching(PNM* img, ImageViewer* iv) :
 
 PNM* HistogramStretching::transform()
 {
+
     int width  = image->width();
     int height = image->height();
-
     PNM* newImage = new PNM(width, height, image->format());
+    Histogram * histogram = image->getHistogram();
 
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    int  maxRed = histogram->getMaxKey(histogram->get(histogram->RChannel));
+    int  minRed = histogram->getMinKey(histogram->get(histogram->RChannel));
 
+    int  maxGreen = histogram->getMaxKey(histogram->get(histogram->GChannel));
+    int  minGreen = histogram->getMinKey(histogram->get(histogram->GChannel));
+
+    int  maxBlue = histogram->getMaxKey(histogram->get(histogram->BChannel));
+    int  minBlue = histogram->getMinKey(histogram->get(histogram->BChannel));
+
+    for(int x  = 0 ; x < width; x++){
+        for (int y = 0 ; y < height; y++) {
+
+           QRgb pixel = image->pixel(x,y);
+           int g = (qGreen(pixel) - minGreen) * (MAX_VALUE/(maxGreen-minGreen));
+           int r = (qRed(pixel) - minRed) * (MAX_VALUE/(maxRed-minRed));
+           int b = (qBlue(pixel) - minBlue) * (MAX_VALUE/(maxBlue-minBlue));
+           newImage->setPixel(x,y,QColor(r,g,b).rgba());
+        }
+    }
     return newImage;
 }
 

src/core/transformations/histogram_stretching.h

@@ -6,6 +6,7 @@
 class HistogramStretching : public Transformation
 {
 public:
+    int const MAX_VALUE = 255;
     HistogramStretching(PNM*);
     HistogramStretching(PNM*, ImageViewer* iv);