diff --git a/src/core/transformations/blur_gaussian.cpp b/src/core/transformations/blur_gaussian.cpp
index 758f178..9fdae67 100644
--- a/src/core/transformations/blur_gaussian.cpp
+++ b/src/core/transformations/blur_gaussian.cpp
@@ -39,6 +39,6 @@ math::matrix<float> BlurGaussian::getMask(int size, Mode)
 
 float BlurGaussian::getGauss(int x, int y, float sigma)
 {    
-    return exp(-((pow(x, 2.0) + pow(y, 2.0)) / 2 * pow(sigma, 2.0))) / (2 * M_PI * pow(sigma, 2.0));
+    return exp(-((pow(x, 2.0) + pow(y, 2.0)) / (2 * pow(sigma, 2.0)))) / (2 * M_PI * pow(sigma, 2.0));
 }
 
diff --git a/src/core/transformations/edge_gradient.cpp b/src/core/transformations/edge_gradient.cpp
index a36a5b8..0557093 100644
--- a/src/core/transformations/edge_gradient.cpp
+++ b/src/core/transformations/edge_gradient.cpp
@@ -1,4 +1,5 @@
 #include "edge_gradient.h"
+#include <math.h>
 
 EdgeGradient::EdgeGradient(PNM* img, ImageViewer* iv) :
     Convolution(img, iv)
@@ -24,8 +25,27 @@ PNM* EdgeGradient::transform()
 {
     PNM* newImage = new PNM(image->width(), image->height(), image->format());
 
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    PNM* horizontal = horizontalDetection();
+    PNM* vertical = verticalDetection();
+
+    for (int x=0;x<image->width();++x) {
+        for (int y=0;y<image->height();++y) {
+            int horizontalPixel = horizontal->pixel(x,y);
+            int verticalPixel = vertical->pixel(x,y);
+
+            int r = sqrt(pow(qRed(horizontalPixel), 2.0) + pow(qRed(verticalPixel), 2.0));
+            int g = sqrt(pow(qGreen(horizontalPixel), 2.0) + pow(qGreen(verticalPixel), 2.0));
+            int b = sqrt(pow(qBlue(horizontalPixel), 2.0) + pow(qBlue(verticalPixel), 2.0));
+
+            newImage->setPixel(x, y, QColor(limit(r),limit(g),limit(b)).rgb());
+        }
+    }
 
     return newImage;
 }
 
+int EdgeGradient::limit(int value) {
+    if (value < 0) return 0;
+    if (value > 255) return 255;
+    return value;
+}
diff --git a/src/core/transformations/edge_gradient.h b/src/core/transformations/edge_gradient.h
index 331ccc1..b030b2c 100644
--- a/src/core/transformations/edge_gradient.h
+++ b/src/core/transformations/edge_gradient.h
@@ -16,6 +16,7 @@ public:
 
 protected:
     virtual void prepareMatrices() = 0;
+    int limit(int value);
     math::matrix<float> g_x,
                         g_y;
 };
diff --git a/src/core/transformations/edge_laplacian.cpp b/src/core/transformations/edge_laplacian.cpp
index 8c26718..851ff61 100644
--- a/src/core/transformations/edge_laplacian.cpp
+++ b/src/core/transformations/edge_laplacian.cpp
@@ -15,7 +15,14 @@ math::matrix<float> EdgeLaplacian::getMask(int, Mode)
     int size = getParameter("size").toInt();
     math::matrix<float> mask(size, size);
 
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    for (int i=0;i<size;++i) {
+        for (int j=0;j<size;++j) {
+            if (i == size/2 && j == size/2)
+                mask[i][j] = (size*size) - 1;
+            else
+                mask[i][j] = -1;
+        }
+    }
 
     return mask;
 }
diff --git a/src/core/transformations/edge_laplacian_of_gauss.cpp b/src/core/transformations/edge_laplacian_of_gauss.cpp
index dcacb71..0ae99f3 100644
--- a/src/core/transformations/edge_laplacian_of_gauss.cpp
+++ b/src/core/transformations/edge_laplacian_of_gauss.cpp
@@ -1,5 +1,5 @@
 #include "edge_laplacian_of_gauss.h"
-
+#include <math.h>
 #include "blur_gaussian.h"
 
 EdgeLaplaceOfGauss::EdgeLaplaceOfGauss(PNM* img) :
@@ -12,23 +12,28 @@ EdgeLaplaceOfGauss::EdgeLaplaceOfGauss(PNM* img, ImageViewer* iv) :
 {
 }
 
-math::matrix<float> EdgeLaplaceOfGauss::getMask(int, Mode)
+math::matrix<float> EdgeLaplaceOfGauss::getMask(int size, float sigma, Mode)
 {
-    size = getParameter("size").toInt();
-    double sigma = getParameter("sigma").toDouble();
+    if (size == 0)
+        size = getParameter("size").toInt();
+    if (sigma == 0)
+        sigma = getParameter("sigma").toDouble();
 
     math::matrix<float> mask(size, size);
 
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    for (int i=0;i<size;++i) {
+        for (int j=0;j<size;++j) {
+            mask[i][j] = getLoG(i - (size/2.0), j - (size/2.0), sigma);
+        }
+    }
 
     return mask;
 }
 
 float EdgeLaplaceOfGauss::getLoG(int x, int y, float s)
 {
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
-
-    return 0;
+    float gauss = BlurGaussian::getGauss(x,y,s);
+    return ((pow(x,2.0) + pow(y,2.0) - 2) * gauss) / pow(s,2.0);
 }
 
 int EdgeLaplaceOfGauss::getSize()
diff --git a/src/core/transformations/edge_laplacian_of_gauss.h b/src/core/transformations/edge_laplacian_of_gauss.h
index d69f564..9f08f70 100644
--- a/src/core/transformations/edge_laplacian_of_gauss.h
+++ b/src/core/transformations/edge_laplacian_of_gauss.h
@@ -9,7 +9,7 @@ public:
     EdgeLaplaceOfGauss(PNM*);
     EdgeLaplaceOfGauss(PNM*, ImageViewer*);
 
-    virtual math::matrix<float> getMask(int, Mode);
+    virtual math::matrix<float> getMask(int, float, Mode);
 
     static float getLoG(int, int, float);
     int getSize();
diff --git a/src/core/transformations/edge_prewitt.cpp b/src/core/transformations/edge_prewitt.cpp
index d6585eb..56faf05 100644
--- a/src/core/transformations/edge_prewitt.cpp
+++ b/src/core/transformations/edge_prewitt.cpp
@@ -14,6 +14,15 @@ EdgePrewitt::EdgePrewitt(PNM*img, ImageViewer* iv) :
 
 void EdgePrewitt::prepareMatrices()
 {
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    float array_x[9] = {-1,0,1,
+                        -1,0,1,
+                        -1,0,1};
+
+    float array_y[9] = {-1,-1,-1,
+                        0,0,0,
+                        1,1,1};
+
+    g_x = math::matrix<float>(3,3, array_x);
+    g_y = math::matrix<float>(3,3, array_y);
 }
 
diff --git a/src/core/transformations/edge_roberts.cpp b/src/core/transformations/edge_roberts.cpp
index 0428da9..a2d7817 100644
--- a/src/core/transformations/edge_roberts.cpp
+++ b/src/core/transformations/edge_roberts.cpp
@@ -1,4 +1,5 @@
 #include "edge_roberts.h"
+#include <math.h>
 
 EdgeRoberts::EdgeRoberts(PNM* img) :
     EdgeGradient(img)
@@ -14,5 +15,15 @@ EdgeRoberts::EdgeRoberts(PNM* img, ImageViewer* iv) :
 
 void EdgeRoberts::prepareMatrices()
 {
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    g_x = math::matrix<float>(2,2);
+    g_x[0][0] = 1;
+    g_x[0][1] = 0;
+    g_x[1][0] = 0;
+    g_x[1][1] = -1;
+
+    g_y = math::matrix<float>(2,2);
+    g_y[0][0] = 0;
+    g_y[0][1] = 1;
+    g_y[1][0] = -1;
+    g_y[1][1] = 0;
 }
diff --git a/src/core/transformations/edge_sobel.cpp b/src/core/transformations/edge_sobel.cpp
index 6ef4bff..1af5820 100644
--- a/src/core/transformations/edge_sobel.cpp
+++ b/src/core/transformations/edge_sobel.cpp
@@ -14,7 +14,16 @@ EdgeSobel::EdgeSobel(PNM* img) :
 
 void EdgeSobel::prepareMatrices()
 {
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    float array_x[9] = {-1,0,1,
+                        -2,0,2,
+                        -1,0,1};
+
+    float array_y[9] = {-1,-2,-1,
+                        0,0,0,
+                        1,2,1};
+
+    g_x = math::matrix<float>(3,3, array_x);
+    g_y = math::matrix<float>(3,3, array_y);
 }
 
 math::matrix<float>* EdgeSobel::rawHorizontalDetection()
diff --git a/src/core/transformations/edge_zero.cpp b/src/core/transformations/edge_zero.cpp
index 541943f..30ecd40 100644
--- a/src/core/transformations/edge_zero.cpp
+++ b/src/core/transformations/edge_zero.cpp
@@ -22,8 +22,24 @@ PNM* EdgeZeroCrossing::transform()
     int    t     = getParameter("threshold").toInt();
 
     PNM* newImage = new PNM(width, height, QImage::Format_Grayscale8);
+    EdgeLaplaceOfGauss log(newImage);
 
-    qDebug() << Q_FUNC_INFO << "Not implemented yet!";
+    int v0 = 128;
+
+    for (int x=0;x<width;++x) {
+        for (int y=0;y<height;++y) {
+            float lapsjan = EdgeLaplaceOfGauss::getLoG(x,y, sigma) * v0;
+            math::matrix<float> mask = log.getMask(size, sigma, RepeatEdge);
+
+            float max = mask.max();
+            float min = mask.min();
+
+            if (min < v0 - t && max > v0 + t)
+                newImage->setPixel(x,y, QColor(lapsjan, lapsjan, lapsjan).rgb());
+            else
+                newImage->setPixel(x,y, QColor(0, 0, 0).rgb());
+        }
+    }
 
     return newImage;
 }