diff --git a/imageviewer-qt4.cpp b/imageviewer-qt4.cpp
index c5e2c73..ab854ad 100644
--- a/imageviewer-qt4.cpp
+++ b/imageviewer-qt4.cpp
@@ -47,6 +47,7 @@
 ImageViewer::ImageViewer() {
   original = NULL;
   working_copy = NULL;
+  histogramm_reference = NULL;
   startLogging();
   generateMainGui();
   renewLogging();
@@ -422,7 +423,15 @@ void ImageViewer::generateControlPanels() {
   task_tab_widget2 = new QWidget();
   task_tab2 = new QVBoxLayout();
   task_tab_widget2->setLayout(task_tab2);
- 
+  
+  reference_histogramm_label = new QLabel();
+  reference_histogramm_label->setBackgroundRole(QPalette::Base);
+  reference_histogramm_label->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding);
+  reference_histogramm_label->setScaledContents(false);
+  
+  reference_stats = new QLabel();
+  reference_stats->setText("Stats for reference image will be shown here.");
+  
   original_histogramm_label = new QLabel();
   original_histogramm_label->setBackgroundRole(QPalette::Base);
   original_histogramm_label->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding);
@@ -460,7 +469,10 @@ void ImageViewer::generateControlPanels() {
   contrast_percentile_slider->setMaximum(100);
   contrast_percentile_slider->setValue(10);  
   QObject::connect(contrast_percentile_slider, SIGNAL(valueChanged(int)), this, SLOT(robustAutomaticContrastAdaption(int)));
-  
+
+  task_tab2->addWidget(new QLabel("Reference image"));
+  task_tab2->addWidget(reference_stats);
+  task_tab2->addWidget(reference_histogramm_label);
   task_tab2->addWidget(new QLabel("Original image"));
   task_tab2->addWidget(original_stats);
   task_tab2->addWidget(original_histogramm_label);
@@ -481,6 +493,11 @@ void ImageViewer::generateControlPanels() {
   task_tab_widget3 = new QWidget();
   task_tab3 = new QVBoxLayout();
   task_tab_widget3->setLayout(task_tab3);
+
+  reference_histogramm_cumulative_label = new QLabel();
+  reference_histogramm_cumulative_label->setBackgroundRole(QPalette::Base);
+  reference_histogramm_cumulative_label->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding);
+  reference_histogramm_cumulative_label->setScaledContents(false);
   
   original_histogramm_cumulative_label = new QLabel();
   original_histogramm_cumulative_label->setBackgroundRole(QPalette::Base);
@@ -495,6 +512,8 @@ void ImageViewer::generateControlPanels() {
   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("Reference image"));
+  task_tab3->addWidget(reference_histogramm_cumulative_label);
   task_tab3->addWidget(new QLabel("Original image"));
   task_tab3->addWidget(original_histogramm_cumulative_label);
   task_tab3->addWidget(new QLabel("Working copy"));
@@ -627,6 +646,36 @@ void ImageViewer::open() {
   }
 }
 
+/**
+ * Simply load another image to provide reference for some operations.
+ * @brief ImageViewer::openReference
+ */
+void ImageViewer::openReference() {
+  if(histogramm_reference != NULL) {
+    delete histogramm_reference;
+    histogramm_reference = NULL;
+  }
+  QString fileName = QFileDialog::getOpenFileName(this, tr("Open Histogramm Reference File"), QDir::currentPath());
+  if(!fileName.isEmpty()) {
+    histogramm_reference = new LazyImage(new QImage(fileName));
+    if(histogramm_reference->getImage()->isNull()) {
+      QMessageBox::information(this, tr("Image Viewer"), tr("Cannot load %1.").arg(fileName));
+      return;
+    }
+    
+    if(histogramm_reference->getImage() != NULL) {
+      histogramm_reference->updateStatistics();
+      QString result = QString("Intensity: Average: %1, Variance: %2").arg(histogramm_reference->getIntensityAverage()).arg(histogramm_reference->getIntensityVariance());
+      reference_stats->setText(result);
+      reference_histogramm_label->setPixmap(QPixmap::fromImage(*(histogramm_reference->getHistogrammNormalImage())));
+      reference_histogramm_cumulative_label->setPixmap(QPixmap::fromImage(*(histogramm_reference->getHistogrammCumulativeImage())));
+    }
+    
+    logFile << "Referenzbild geladen: " << fileName.toStdString().c_str()  << std::endl;
+    renewLogging();
+  }
+}
+
 void ImageViewer::resizeEvent(QResizeEvent* event) {
   QMainWindow::resizeEvent(event);
   centralwidget->setMinimumWidth(width());
@@ -680,6 +729,10 @@ void ImageViewer::createActions() {
   openAct->setShortcut(tr("Ctrl+O"));
   connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
 
+  openHistAct = new QAction(tr("Open &Reference..."), this);
+  openHistAct->setShortcut(tr("Ctrl+O"));
+  connect(openHistAct, SIGNAL(triggered()), this, SLOT(openReference()));
+  
   printAct = new QAction(tr("&Print..."), this);
   printAct->setShortcut(tr("Ctrl+P"));
   printAct->setEnabled(false);
@@ -720,6 +773,7 @@ void ImageViewer::createActions() {
 void ImageViewer::createMenus() {
   fileMenu = new QMenu(tr("&File"), this);
   fileMenu->addAction(openAct);
+  fileMenu->addAction(openHistAct);
   fileMenu->addAction(printAct);
   fileMenu->addSeparator();
   fileMenu->addAction(exitAct);
diff --git a/imageviewer-qt4.h b/imageviewer-qt4.h
index 2ad91ed..3c49e95 100644
--- a/imageviewer-qt4.h
+++ b/imageviewer-qt4.h
@@ -88,8 +88,10 @@ class ImageViewer : public QMainWindow {
     QWidget* task_tab_widget2;
     QVBoxLayout* task_tab2;
 
+    QLabel* reference_stats;
     QLabel* original_stats;
     QLabel* stats;
+    QLabel* reference_histogramm_label;
     QLabel* original_histogramm_label;
     QLabel* histogramm_label;
     QPushButton* analyze_image;
@@ -103,6 +105,7 @@ class ImageViewer : public QMainWindow {
     QWidget* task_tab_widget3;
     QVBoxLayout* task_tab3;
     
+    QLabel* reference_histogramm_cumulative_label;
     QLabel* original_histogramm_cumulative_label;
     QLabel* histogramm_cumulative_label;
     
@@ -111,6 +114,7 @@ class ImageViewer : public QMainWindow {
     // "My" space for storing data/results
     LazyImage* original;
     LazyImage* working_copy;
+    LazyImage* histogramm_reference;
 
   private slots:
     // Custom slots
@@ -127,6 +131,7 @@ class ImageViewer : public QMainWindow {
     void linearHistogrammAdaption();
 
     void open();
+    void openReference();
     void print();
     void zoomIn();
     void zoomOut();
@@ -175,6 +180,7 @@ class ImageViewer : public QMainWindow {
 #endif
 
     QAction *openAct;
+    QAction *openHistAct;
     QAction *printAct;
     QAction *exitAct;
     QAction *zoomInAct;