diff --git a/canny_edge_machine.cpp b/canny_edge_machine.cpp
index 2a23157..d9eaa3c 100644
--- a/canny_edge_machine.cpp
+++ b/canny_edge_machine.cpp
@@ -290,6 +290,22 @@ class CannyEdgeMachine {
       this->showEdges();
     };
     
+    void doFirstStep(void) {
+      this->reset();
+      this->doGaussBlur(); // uses filter_size, filter_sigma
+      this->doGradiants();
+      this->doGradiantMagnitude();      
+    };
+    
+    void doSecondStep(void) {
+      this->filterLocalMaxima(); // uses t_low only
+    };
+    
+    void doThirdStep(void) {
+      this->workLocalMaxima(); // uses t_low & t_high
+      this->showEdges();      
+    };
+    
 };
 
 #endif
diff --git a/imageviewer-qt4.cpp b/imageviewer-qt4.cpp
index 61320b1..a5c7f25 100644
--- a/imageviewer-qt4.cpp
+++ b/imageviewer-qt4.cpp
@@ -48,6 +48,7 @@ ImageViewer::ImageViewer() {
   original = NULL;
   working_copy = NULL;
   histogramm_reference = NULL;
+  canny_edge_machine = NULL;
   startLogging();
   generateMainGui();
   renewLogging();
@@ -649,16 +650,69 @@ void ImageViewer::applyBasicFilterWithOverflowHandling() {
  * @brief ImageViewer::runCannyEdge 
  */
 void ImageViewer::runCannyEdge(void) {
-  CannyEdgeMachine cem = CannyEdgeMachine(original, working_copy);
   int filter_size = gauss_filter_size->value();
   double filter_sigma = gauss_filter_sigma->value();
   double t_low = t_low_spinbox->value();
   double t_high = t_high_spinbox->value();
   logFile << "Canny-Edge using N*N filter size: " << filter_size << ", filter sigma: " << filter_sigma << ", and thresholds: " << t_low << ", " << t_high << std::endl;
   renewLogging();
-  cem.setGaussFilterParams(filter_size, filter_sigma);
-  cem.setThresholdValues(t_low, t_high);
-  cem.work();
+  canny_edge_machine->setGaussFilterParams(filter_size, filter_sigma);
+  canny_edge_machine->setThresholdValues(t_low, t_high);
+  canny_edge_machine->work();
+  updateImageDisplay();  
+}
+
+/**
+ * Does the first step of canny edge.
+ * 
+ * @brief ImageViewer::runCannyEdgeFirstStep
+ */
+void ImageViewer::runCannyEdgeFirstStep(void) {
+  int filter_size = gauss_filter_size->value();
+  double filter_sigma = gauss_filter_sigma->value();
+  double t_low = t_low_spinbox->value();
+  double t_high = t_high_spinbox->value();
+  logFile << "[Step 1] Canny-Edge using N*N filter size: " << filter_size << ", filter sigma: " << filter_sigma << ", and thresholds: " << t_low << ", " << t_high << std::endl;
+  renewLogging();
+  canny_edge_machine->setGaussFilterParams(filter_size, filter_sigma);
+  canny_edge_machine->setThresholdValues(t_low, t_high);
+  canny_edge_machine->doFirstStep();
+  updateImageDisplay();  
+}
+
+/**
+ * Does the second step of canny edge.
+ * 
+ * @brief ImageViewer::runCannyEdgeSecondStep
+ */
+void ImageViewer::runCannyEdgeSecondStep(void) {
+  int filter_size = gauss_filter_size->value();
+  double filter_sigma = gauss_filter_sigma->value();
+  double t_low = t_low_spinbox->value();
+  double t_high = t_high_spinbox->value();
+  logFile << "[Step 2] Canny-Edge using N*N filter size: " << filter_size << ", filter sigma: " << filter_sigma << ", and thresholds: " << t_low << ", " << t_high << std::endl;
+  renewLogging();
+  canny_edge_machine->setGaussFilterParams(filter_size, filter_sigma);
+  canny_edge_machine->setThresholdValues(t_low, t_high);
+  canny_edge_machine->doSecondStep();
+  updateImageDisplay();  
+}
+
+/**
+ * Does the third step of canny edge.
+ * 
+ * @brief ImageViewer::runCannyEdgeThirdStep
+ */
+void ImageViewer::runCannyEdgeThirdStep(void) {
+  int filter_size = gauss_filter_size->value();
+  double filter_sigma = gauss_filter_sigma->value();
+  double t_low = t_low_spinbox->value();
+  double t_high = t_high_spinbox->value();
+  logFile << "[Step 3] Canny-Edge using N*N filter size: " << filter_size << ", filter sigma: " << filter_sigma << ", and thresholds: " << t_low << ", " << t_high << std::endl;
+  renewLogging();
+  canny_edge_machine->setGaussFilterParams(filter_size, filter_sigma);
+  canny_edge_machine->setThresholdValues(t_low, t_high);
+  canny_edge_machine->doThirdStep();
   updateImageDisplay();  
 }
 /**************************************************************************************** 
@@ -922,9 +976,18 @@ void ImageViewer::generateControlPanels() {
   task_tab5_scrolllayout->setSizeConstraint(QLayout::SetMaximumSize);
   task_tab5_scrollwidget->setLayout(task_tab5_scrolllayout);
   
-  run_canny_edge = new QPushButton("Run canny edge algorithm!");
+  run_canny_edge = new QPushButton("Run whole canny edge algorithm!");
   QObject::connect(run_canny_edge, SIGNAL(clicked()), this, SLOT(runCannyEdge()));
   
+  run_canny_edge_first_step = new QPushButton("Do gaussian blur and do gradiants");
+  QObject::connect(run_canny_edge_first_step, SIGNAL(clicked()), this, SLOT(runCannyEdgeFirstStep()));
+  
+  run_canny_edge_second_step = new QPushButton("Filter local maxima");
+  QObject::connect(run_canny_edge_second_step, SIGNAL(clicked()), this, SLOT(runCannyEdgeSecondStep()));
+  
+  run_canny_edge_third_step = new QPushButton("Work local maxima, show result");
+  QObject::connect(run_canny_edge_third_step, SIGNAL(clicked()), this, SLOT(runCannyEdgeThirdStep()));
+  
   gauss_filter_size = new QDoubleSpinBox();
   gauss_filter_size->setDecimals(0);
   gauss_filter_size->setMinimum(3);
@@ -946,10 +1009,13 @@ void ImageViewer::generateControlPanels() {
   task_tab5_scrolllayout->addWidget(gauss_filter_size);
   task_tab5_scrolllayout->addWidget(new QLabel("Gauss filter sigma"));
   task_tab5_scrolllayout->addWidget(gauss_filter_sigma);
+  task_tab5_scrolllayout->addWidget(run_canny_edge_first_step);
   task_tab5_scrolllayout->addWidget(new QLabel("Low threshold value"));
   task_tab5_scrolllayout->addWidget(t_low_spinbox);
+  task_tab5_scrolllayout->addWidget(run_canny_edge_second_step);
   task_tab5_scrolllayout->addWidget(new QLabel("High threshold value"));
   task_tab5_scrolllayout->addWidget(t_high_spinbox);
+  task_tab5_scrolllayout->addWidget(run_canny_edge_third_step);
   task_tab5_scrolllayout->addWidget(run_canny_edge);
   
   tabWidget->addTab(task_tab5_widget, "Task #5");
@@ -1057,6 +1123,10 @@ void ImageViewer::open() {
     delete original;
     original = NULL;
   }
+  if(canny_edge_machine != NULL) {
+    delete canny_edge_machine;
+    canny_edge_machine = NULL;
+  }
   QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), QDir::currentPath());
   if(!fileName.isEmpty()) {
     working_copy = new LazyImage(new QImage(fileName));
@@ -1065,6 +1135,7 @@ void ImageViewer::open() {
       QMessageBox::information(this, tr("Image Viewer"), tr("Cannot load %1.").arg(fileName));
       return;
     }
+    canny_edge_machine = new CannyEdgeMachine(original, working_copy);
     scaleFactor = 1.0;
     updateImageDisplay();
     printAct->setEnabled(true);
diff --git a/imageviewer-qt4.h b/imageviewer-qt4.h
index f7c90d6..921256c 100644
--- a/imageviewer-qt4.h
+++ b/imageviewer-qt4.h
@@ -152,11 +152,15 @@ class ImageViewer : public QMainWindow {
     QDoubleSpinBox* t_low_spinbox;    
     QDoubleSpinBox* t_high_spinbox;
     QPushButton* run_canny_edge;
+    QPushButton* run_canny_edge_first_step;
+    QPushButton* run_canny_edge_second_step;
+    QPushButton* run_canny_edge_third_step;
     
     // "My" space for storing data/results
     LazyImage* original;
     LazyImage* working_copy;
     LazyImage* histogramm_reference;
+    CannyEdgeMachine* canny_edge_machine;
 
   private slots:
     // Custom slots
@@ -177,6 +181,9 @@ class ImageViewer : public QMainWindow {
     void applyBasicFilter();
     void applyBasicFilterWithOverflowHandling();
     void runCannyEdge(void);
+    void runCannyEdgeFirstStep(void);
+    void runCannyEdgeSecondStep(void);
+    void runCannyEdgeThirdStep(void);
 
     void open();
     void openReference();