Add Edge Detection Filters

Edge_Detection_Filters/Laplacian.m

@@ -0,0 +1,25 @@
+pkg load image;
+
+img = rgb2gray(imread("deer1.jpg"));
+subplot(1,2,1);
+imshow(img);
+title('Original Image');
+
+img = double(img);
+h = [-1,2,-1;2,-4,2;-1,2,-1];
+oimg = zeros(rows(img),columns(img));
+
+for i=2:rows(img)-1
+  for j=2:columns(img)-1
+     a =img(i-1,j-1)*h(1) + img(i-1,j)*h(2) + img(i-1,j+1)*h(3) + img(i,j-1)*h(4) + img(i,j)*h(5) + img(i,j+1)*h(6) + img(i+1,j-1)*h(7) + img(i+1,j)*h(8) + img(i+1,j+1)*h(9); %sum(sum(img(i-1:i+1,j-1:j+1) .* h));
+     if(a<0)
+        oimg(i,j) = 0;
+     else
+        oimg(i,j) = a;
+     end   
+  end
+end
+
+subplot(1,2,2);
+imshow(uint8(oimg));
+title('On Applying Laplacian High Pass Filter');

Edge_Detection_Filters/Prewitt.m

@@ -0,0 +1,25 @@
+pkg load image;
+
+img = rgb2gray(imread("deer1.jpg"));
+subplot(1,2,1);
+imshow(img);
+title('Original Image');
+
+img = double(img);
+h = [-2,-1,0;-1,0,1;0,1,2];
+oimg = zeros(rows(img),columns(img));
+
+for i=2:rows(img)-1
+  for j=2:columns(img)-1
+     a = sum(sum(img(i-1:i+1,j-1:j+1) .* h));
+     if(a<0)
+        oimg(i,j) = 0;
+     else
+        oimg(i,j) = a;
+     end   
+  end
+end
+
+subplot(1,2,2);
+imshow(uint8(oimg));
+title('On Applying Prewitt High Pass Filter');

Edge_Detection_Filters/Robert.m

@@ -0,0 +1,38 @@
+pkg load image;
+
+img = rgb2gray(imread("deer1.jpg"));
+subplot(1,2,1);
+imshow(img);
+title('Original Image');
+
+img = double(img);
+r1 = [1,0;0,-1];
+oimg = zeros(rows(img),columns(img));
+
+for i=1:rows(img)-1
+  for j=1:columns(img)-1
+     a = img(i,j)*r1(1) + img(i,j+1)*r1(2) + img(i+1,j)*r1(3) + img(i+1,j+1)*r1(4);
+     if(a<0)
+        oimg(i,j) = 0;
+     else
+        oimg(i,j) = a;
+     end   
+  end
+end
+
+r2 = [0,1;-1,0];
+
+for i=1:rows(img)-1
+  for j=1:columns(img)-1
+     a = img(i,j)*r2(1) + img(i,j+1)*r2(2) + img(i+1,j)*r2(3) + img(i+1,j+1)*r2(4);
+     if(a<0)
+        oimg(i,j+1) = oimg(i,j+1) + 0;
+     else
+        oimg(i,j+1) = oimg(i,j+1) + a;
+     end   
+  end
+end
+
+subplot(1,2,2);
+imshow(uint8(oimg));
+title('On Applying Robert High Pass Filter');

Edge_Detection_Filters/Sobel.m

@@ -0,0 +1,25 @@
+pkg load image;
+
+img = rgb2gray(imread("deer1.jpg"));
+subplot(1,2,1);
+imshow(img);
+title('Original Image');
+
+img = double(img);
+h = [-2,-2,0;-2,0,2;0,2,2];
+oimg = zeros(rows(img),columns(img));
+
+for i=2:rows(img)-1
+  for j=2:columns(img)-1
+     a = sum(sum(img(i-1:i+1,j-1:j+1) .* h));
+     if(a<0)
+        oimg(i,j) = 0;
+     else
+        oimg(i,j) = a;
+     end   
+  end
+end
+
+subplot(1,2,2);
+imshow(uint8(oimg));
+title('On Applying Sobel High Pass Filter');

README.md

@@ -12,4 +12,4 @@ This repository contains some of the programs written for the course **Digital S
 * [Point Processing techniques in Spatial domain](./Point_Processing_Techniques)
 * [Contrast Stretching and Histogram Equalization](./Contrast_Stretching_and_Histogram_Equalization)
 * [Filters](./Filters)
-
+* [Edge Detection Filters](./Edge_Detection_Filters)