Edge Detection Using the Sobel Operator Extract the edges from the test Image us

Question

Edge Detection Using the Sobel Operator Extract the edges from the test Image using the Sobel edge detector. [I_sobl, t1] = edge(I, 'sobel'); figure, subplot(2, 2, 1), imshow(I), title('Original Image'); subplot(2, 2, 2), imshow(I_sobl), title('Sobel, default thresh'); Extract the edges from the test Image with Gaussian noise using the Sobel edge detector. [I_sob2, t2] = edge(I_noise, 'sobel'); subplot(2, 2, 3), imshow(I_noise), title('Image w/noise'); subplot(2, 2, 4), imshow(I_sob2), title('Sobel on noise'); How does the Sobel operator compare with the Prewitt operator with and without noise?

Explanation / Answer

clc;
close all;
clear all;

[IMG2,map] = imread('lenna.jpg');
IMG1 = (rgb2gray(IMG2));
I_noise = imnoise(IMG1,'gaussian');

figure
imshow(IMG2);

% 4
[I_sob1,t1] = edge(IMG1,'sobel');
figure, subplot(2,2,1),imshow(IMG1),title('Original image');
subplot(2,2,2),imshow(I_sob1),title('Sobel, default threshold');

% 5
[I_sob2,t1] = edge(I_noise,'sobel');
subplot(2,2,3),imshow(I_noise),title('Image w/ noise');
subplot(2,2,4),imshow(I_sob2),title('Sobel on noise');

%QUESTION 5
figure
subplot(2,2,1),imshow(I_sob1),title('Sobel w/o noise');
subplot(2,2,2),imshow(I_sob2),title('Sobel w/ noise');

[I_prw2,t2] = edge(IMG1,'prewitt');
[I_prw1,t2] = edge(I_noise,'prewitt');
subplot(2,2,4),imshow(I_prw1),title('Prewitt w/o noise');
subplot(2,2,3),imshow(I_prw2),title('Prewitt w/ noise');

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