[TASK] Implement linear histogramm adaption

imageviewer-qt4.cpp

@@ -316,6 +316,33 @@ void ImageViewer::robustAutomaticContrastAdaption(int c_param) {
   renewLogging();
 }
 
+/**
+ * Do a very basic, linear histogramm adaption.
+ * 
+ * @brief ImageViewer::linearHistogrammAdaption
+ */
+void ImageViewer::linearHistogrammAdaption(void) {
+  logFile << "Doing linear histogramm adaption ..." << std::endl;
+  renewLogging();
+  int h, s, l;
+  int* ach = original->getAbsoluteCumulativeIntensityHistogramm();
+  int pixels = working_copy->getImage()->width()*working_copy->getImage()->height();
+  for(int x=0; x<working_copy->getImage()->width(); x++) {
+    for(int y=0; y<working_copy->getImage()->height(); y++) {
+      QColor color = QColor::fromRgb(original->getImage()->pixel(x, y));
+      color.getHsl(&h, &s, &l);
+      
+      l = (int) qFloor(ach[l] * (255.0/pixels));
+      
+      color.setHsl(h, s, l);
+      working_copy->getImage()->setPixel(x, y, color.rgb());
+    }
+  }  
+  updateImageDisplay();
+  logFile << "done." << std::endl;
+  renewLogging();
+}
+
 
 /**************************************************************************************** 
 *   
@@ -408,8 +435,7 @@ void ImageViewer::generateControlPanels() {
   contrast_percentile_slider = new QSlider(Qt::Horizontal);
   contrast_percentile_slider->setMinimum(0);
   contrast_percentile_slider->setMaximum(100);
-  contrast_percentile_slider->setValue(10);
-  
+  contrast_percentile_slider->setValue(10);  
   QObject::connect(contrast_percentile_slider, SIGNAL(valueChanged(int)), this, SLOT(robustAutomaticContrastAdaption(int)));
   
   task_tab2->addWidget(new QLabel("Original image"));
@@ -443,10 +469,14 @@ void ImageViewer::generateControlPanels() {
   histogramm_cumulative_label->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding);
   histogramm_cumulative_label->setScaledContents(false);
 
+  linear_histogramm_adaption = new QPushButton("Do linear histogramm adaption (basic)");
+  QObject::connect(linear_histogramm_adaption, SIGNAL(clicked()), this, SLOT(linearHistogrammAdaption()));
+   
   task_tab3->addWidget(new QLabel("Original image"));
   task_tab3->addWidget(original_histogramm_cumulative_label);
   task_tab3->addWidget(new QLabel("Working copy"));
   task_tab3->addWidget(histogramm_cumulative_label);
+  task_tab3->addWidget(linear_histogramm_adaption);
   
   tabWidget->addTab(task_tab_widget3, "Task #3");
   

imageviewer-qt4.h

@@ -105,6 +105,8 @@ class ImageViewer : public QMainWindow {
     QLabel* original_histogramm_cumulative_label;
     QLabel* histogramm_cumulative_label;
     
+    QPushButton* linear_histogramm_adaption;
+    
     // "My" space for storing data/results
     LazyImage* original;
     LazyImage* working_copy;
@@ -120,6 +122,7 @@ class ImageViewer : public QMainWindow {
     void convertToMonochrome();
     void resetWorkingCopy();
     void robustAutomaticContrastAdaption(int c_param);
+    void linearHistogrammAdaption();
 
     void open();
     void print();

lazy_image.cpp

@@ -17,6 +17,7 @@ class LazyImage {
     QImage* histogramm_cumulative_image;
     double histogramm_relative_intensity[256];
     int histogramm_absolute_intensity[256];
+    int histogramm_absolute_cumulative_intensity[256];
     int intensity_average;
     int intensity_variance;
     
@@ -25,6 +26,7 @@ class LazyImage {
       for(int i=0; i<256; i++) {
 	histogramm_relative_intensity[i] = 0;
 	histogramm_absolute_intensity[i] = 0;
+	histogramm_absolute_cumulative_intensity[i] = 0;
       }      
       // Count all the brightness values
       for(int x=0; x<this->img->width(); x++) {
@@ -35,11 +37,15 @@ class LazyImage {
 	  int intensity = this->calcIntensity(r, g, b);
 	  histogramm_absolute_intensity[intensity] += 1;
 	}
-      }      
-      // Calculate relative histogramm
+      }
+      
+      // Calculate relative histogramm and absolute cumulative histogramm
       int pixels = this->img->width()*this->img->height();
+      int sum = 0;
       for(int i=0; i<256; i++) {
 	histogramm_relative_intensity[i] = (((double) histogramm_absolute_intensity[i])/((double) pixels));
+	sum += histogramm_absolute_intensity[i];
+	histogramm_absolute_cumulative_intensity[i] = sum;
       }
     };
     
@@ -166,7 +172,11 @@ class LazyImage {
     int* getAbsoluteIntensityHistogramm(void) {
       return this->histogramm_absolute_intensity;
     };
-
+    
+    int* getAbsoluteCumulativeIntensityHistogramm(void) {
+      return this->histogramm_absolute_cumulative_intensity;
+    };
+    
     double* getRelativeIntensityHistogramm(void) {
       return this->histogramm_relative_intensity;
     };