Implementing Edge Detection Techniques to an Original Image

Lenna = imread('Lenna2.jpg');

figure;   SobLenna = edge(Lenna, 'sobel', 0.055, 'horizontal');

subplot(1,3,1);  imshow(SobLenna); xlabel('Horizontal');

SobLenna = edge(Lenna, 'sobel', 0.055, 'vertical'); 

subplot(1,3,2);  imshow(SobLenna); xlabel('Vertical'); title('Sobel Edge Detection');

SobLenna = edge(Lenna, 'sobel', 0.055, 'both');

subplot(1,3,3);  imshow(SobLenna); xlabel('Both');

figure;   PreLenna = edge(Lenna, 'prewitt', 0.055, 'horizontal');

subplot(1,3,1);  imshow(PreLenna); xlabel('Horizontal');

PreLenna = edge(Lenna, 'prewitt', 0.055, 'vertical'); 

subplot(1,3,2);  imshow(PreLenna); xlabel('Vertical'); title('Prewitt Edge Detection');

PreLenna = edge(Lenna, 'prewitt', 0.055, 'both');

subplot(1,3,3);  imshow(PreLenna); xlabel('Both');

figure;   RobLenna = edge(Lenna, 'roberts');

subplot(1,3,1);  imshow(RobLenna); xlabel('With Default Threshold');

RobLenna = edge(Lenna, 'roberts', 0.055);

subplot(1,3,2);  imshow(RobLenna); xlabel('Threshold = 0.055'); title('Roberts Edge Detection');

RobLenna = edge(Lenna, 'roberts', 0.1);

subplot(1,3,3);  imshow(RobLenna); xlabel('Threshold = 0.1');

figure;   LogLenna = edge(Lenna, 'log');

subplot(1,3,1);  imshow(LogLenna); xlabel('With Default Threshold & Sigma');

LogLenna = edge(Lenna, 'log', 0.0055);

subplot(1,3,2);  imshow(LogLenna); xlabel('Threshold = 0.0055 & Default Sigma');

title('Laplacian of Gaussian Edge Detection');

LogLenna = edge(Lenna, 'log', 0.0055, 1.5);

subplot(1,3,3);  imshow(LogLenna); xlabel('Threshold = 0.0055 & Sigma = 1.5');

figure;   CanLenna = edge(Lenna, 'canny');

subplot(1,3,1);  imshow(CanLenna); xlabel('With Default Threshold & Sigma');

CanLenna = edge(Lenna, 'canny', 0.155);

subplot(1,3,2);  imshow(CanLenna); xlabel('Threshold = 0.155 & Default Sigma');

title('Canny Edge Detection');

CanLenna = edge(Lenna, 'canny', 0.155, 1.25);

subplot(1,3,3);  imshow(CanLenna); xlabel('Threshold = 0.155 & Sigma = 1.25');