histogram equalization

src/core/transformations/histogram_equalization.cpp

@@ -1,6 +1,6 @@
 #include "histogram_equalization.h"
+
 #include "../histogram.h"
-#include <cmath> // Dla funkcji round
 
 HistogramEqualization::HistogramEqualization(PNM* img) :
     Transformation(img)
@@ -14,44 +14,77 @@ HistogramEqualization::HistogramEqualization(PNM* img, ImageViewer* iv) :
 
 PNM* HistogramEqualization::transform()
 {
-    int width = image->width();
-    int height = image->height();
+    float width = image->width();
+    float height = image->height();
 
-    // Tworzymy nowy obiekt PNM do przechowywania przetworzonego obrazu
     PNM* newImage = new PNM(width, height, image->format());
+    Histogram* histogram = image->getHistogram();
 
-    // Tworzymy histogram dla obecnego obrazu
-    Histogram* hist = image->getHistogram(); // Nie przekazujemy argumentów
+    QHash<int, int>* R = histogram->get(Histogram::RChannel);
+    QHash<int, int>* G = histogram->get(Histogram::GChannel);
+    QHash<int, int>* B = histogram->get(Histogram::BChannel);
+    QHash<int, int>* L = histogram->get(Histogram::LChannel);
 
-    // Pobieramy łączną liczbę pikseli na obrazie
-    int totalPixels = width * height;
+    // Probability tables
+    float redProb[255];
+    float greenProb[255];
+    float blueProb[255];
+    float greyProb[255];
 
-    // Tworzymy dystrybuantę
-    QVector<double> cdf(256, 0.0); // Inicjalizujemy wszystkie wartości na 0.0
-    double sum = 0.0;
-    for (int i = 0; i < 256; ++i) {
-        sum += hist->get(Histogram::LChannel)->value(i) / static_cast<double>(totalPixels); // Używamy kanału luminancji
-        cdf[i] = sum;
+    float pixelSum = width * height;
+    for (int i = 0; i < 256; i++)
+    {
+        redProb[i] = (R->value(i)) / (pixelSum);
+        greenProb[i] = (G->value(i)) / (pixelSum);
+        blueProb[i] = (B->value(i)) / (pixelSum);
+        greyProb[i] = (L->value(i)) / (pixelSum);
     }
 
-    // Normalizujemy dystrybuantę do przedziału [0, 255]
-    QVector<int> lookupTable(256, 0);
-    for (int i = 0; i < 256; ++i) {
-        lookupTable[i] = round(cdf[i] * 255);
+    // D look-up
+    float redD[255];
+    float greenD[255];
+    float blueD[255];
+    float greyD[255];
+
+    // Create template values
+    float sumRed = 0;
+    float sumGreen = 0;
+    float sumBlue = 0;
+    float sumGrey = 0;
+
+    for(int i = 0; i < 255; i++)
+    {
+        sumRed = redProb[i] + sumRed;
+        redD[i] = sumRed;
+
+        sumGreen = greenProb[i] + sumGreen;
+        greenD[i] = sumGreen;
+
+        sumBlue = blueProb[i] + sumBlue;
+        blueD[i] = sumBlue;
+
+        sumGrey= greyProb[i] + sumGrey;
+        greyD[i] = sumGrey;
     }
 
-    // Przeprowadzamy wyrównywanie histogramu
-    for (int y = 0; y < height; ++y) {
-        for (int x = 0; x < width; ++x) {
+    for (int x = 0; x < image->width(); x++)
+    {
+        for (int y = 0; y < image->height(); y++)
+        {
             QRgb pixel = image->pixel(x, y);
-            int grayValue = qGray(pixel); // Pobieramy wartość odcienia szarości
-
-            // Używamy wartości z lookupTable jako nowej wartości odcienia szarości
-            int newGrayValue = lookupTable[grayValue];
-            QRgb newPixel = qRgb(newGrayValue, newGrayValue, newGrayValue); // Ustawiamy nową wartość dla każdego kanału RGB
-
-            // Ustawiamy nowy piksel na obrazie docelowym
-            newImage->setPixel(x, y, newPixel);
+            if (image->format() == QImage::Format_RGB32) {
+                newImage->setPixel(
+                            x,
+                            y,
+                            QColor(
+                                redD[qRed(pixel)] * 255,
+                                greenD[qGreen(pixel)] * 255,
+                                blueD[qBlue(pixel)] * 255
+                            ).rgb());
+            }
+            else {
+                newImage->setPixel(x, y, greyD[qGray(pixel)] * 255);
+            }
         }
     }
 

src/core/transformations/histogram_stretching.cpp

@@ -20,42 +20,76 @@ PNM* HistogramStretching::transform()
     PNM* newImage = new PNM(width, height, image->format());
     Histogram* histogram = image->getHistogram();
 
-    int minValue = -1;
-    int maxValue = -1;
+    int maxRed = 255, maxGreen = 255, maxBlue = 255, maxGrey = 255;
 
-    for (int y = 0; y < image->height(); ++y) {
-        for (int x = 0; x < image->width(); ++x) {
-            if (histogram->get(Histogram::LChannel)->value(x + y * x) != 0)
-            {
-                minValue = histogram->get(Histogram::LChannel)->value(x + y * x);
-                break;
-            }
+    int minRed = 0, minGreen = 0, minBlue = 0, minGrey = 0;
+
+    QHash<int, int>* R = histogram->get(histogram->RChannel);
+    QHash<int, int>* G = histogram->get(histogram->GChannel);
+    QHash<int, int>* B = histogram->get(histogram->BChannel);
+    QHash<int, int>* L = histogram->get(histogram->LChannel);
+
+    for (int i=0; i<256; i++)
+    {
+        if (R->value(minRed) == 0) {
+            minRed++;
+        }
+
+        if (G->value(minGreen) == 0) {
+            minGreen++;
+        }
+
+        if (B->value(minBlue) == 0) {
+            minBlue++;
+        }
+
+        if (L->value(minGrey) == 0) {
+            minGrey++;
         }
     }
 
-    for (int y = image->height(); y > 0; --y) {
-        for (int x = image->width(); x < 0; --x) {
-            if (histogram->get(Histogram::LChannel)->value(x + y * x) != 0)
-            {
-                minValue = histogram->get(Histogram::LChannel)->value(x + y * x);
-                break;
-            }
+    for (int i=256; i>0; i--)
+    {
+        if (R->value(maxRed) == 0) {
+            maxRed--;
+        }
+
+        if (G->value(maxGreen) == 0) {
+            maxGreen--;
+        }
+
+        if (B->value(maxBlue) == 0) {
+            maxBlue--;
+        }
+
+        if (L->value(maxGrey) == 0) {
+            maxGrey--;
         }
     }
 
-    for (int y = 0; y < image->height(); ++y) {
-        for (int x = 0; x < image->width(); ++x) {
-            QRgb pixel = image->pixel(x, y);
+    for (int x = 0; x < image->width(); x++) {
+        for (int y = 0; y < image->height(); y++) {
+           QRgb p = image->pixel(x, y);
 
-            int red = qRed(pixel);
-            int green = qGreen(pixel);
-            int blue = qBlue(pixel);
+           if(image->format() == QImage::Format_RGB32) {
+               int red = qRed(p);
+               int green = qGreen(p);
+               int blue = qBlue(p);
 
-            int stretchedRed = (255 * (red - minValue)) / (maxValue - minValue);
-            int stretchedGreen = (255 * (green - minValue)) / (maxValue - minValue);
-            int stretchedBlue = (255 * (blue - minValue)) / (maxValue - minValue);
-
-            newImage->setPixel(x, y, qRgb(stretchedRed, stretchedGreen, stretchedBlue));
+               newImage->setPixel(
+                           x,
+                           y,
+                           QColor(
+                               (255 / (maxRed - minRed)) * (red - minRed),
+                               (255 / (maxGreen - minGreen)) * (green - minGreen),
+                               (255 / (maxBlue - minBlue)) * (blue - minBlue)
+                           ).rgb());
+           } else {
+               newImage->setPixel(
+                           x,
+                           y,
+                           (255 / (maxGrey - minGrey)) * (qGray(p) - minGrey));
+           }
         }
     }