Code for png image using sobel operator
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cc = imread('CocaCola.png');
cc = imread('CocaCola.png');
cc = uint8(cc);
figure, imshow(cc); title('cc');
cc = rgb2gray(cc);
cc = double(cc);
edg = edgy(cc);
% Pre-allocate the filtered_image matrix with zeros
edg = zeros(size(cc));
Mx = [-1 0 1; -2 0 2; -1 0 1];
My = [-1 -2 -1; 0 0 0; 1 2 1];
for i = 1:size(cc, 1) - 2
for j = 1:size(cc, 2) - 2
% Gradient approximations
Gx = sum(sum(Mx.*cc(i:i+2, j:j+2)));
Gy = sum(sum(My.*cc(i:i+2, j:j+2)));
% Calculate magnitude of vector
edg(i+1, j+1) = sqrt(Gx.^2 + Gy.^2);
end
end
edg = uint8(edg);
figure, imshow(edg); title('edg');
thresholdValue = 100; % varies between [0 255]
output_image = max(edg, thresholdValue);
output_image(output_image == round(thresholdValue)) = 0;
output_image = im2bw(output_image);
figure, imshow(output_image); title('Edge Detected Image');
I wrote this code but did't work .please help
0 comentarios
Respuestas (3)
Fatih Yurekli
el 16 de Oct. de 2020
Editada: Walter Roberson
el 27 de Dic. de 2020
function [c3] = edgy(c)
s1 = [-1 0 1;-2 0 2;-1 0 1];
s1 = double(s1);
s2 = [1 2 1; 0 0 0;-1 -2 -1];
s2 = double(s2);
c = double(c);
[M N] = size(c);
for i = 1:M-2
for j = 1:N-2
a = c(i:i+2, j:j+2);
a1 = a.*s1;
a2 = a.*s2;
b1= 0;
b2= 0;
for k = 1:3
for l = 1:3
b1 = b1+a1(k,l);
b2 = b2+a2(k,l);
end
end
c1(i,j) =b1;
c2(i,j) = b2;
end
end
c3 = sqrt(c1.^2+c2.^2);
c3 = uint8(c3);
end
14 comentarios
Walter Roberson
el 27 de Dic. de 2020
Note: it is 7am my time and I have been up all night doing research and answering questions. I am in bed, assisting multiple people at the same time, and hoping to fall asleep.
Image Analyst
el 27 de Dic. de 2020
Prashanth, you know you can click the "Copy code" icon in the upper right of the code blocks here in answers. You don't have to re-type all this in to your MATLAB, which could introduce typos.
Sulaymon Eshkabilov
el 7 de Sept. de 2020
Editada: Sulaymon Eshkabilov
el 7 de Sept. de 2020
Hi,
Here is the simple solution with MATLAB's builtin function of Image Processing Toolbox that works quite well:
COCA = imread('CC.png');
BW1 = edge(COCA,'sobel');
figure;
imshow(BW1)
title('Sobel Filter');
2 comentarios
Génesis Vivas
el 24 de Sept. de 2020
Editada: Génesis Vivas
el 24 de Sept. de 2020
Hi friend, I think that your problem is that you started in for i = 1:size(cc, 1) - 2, you shouldnt take the border, i=1, what you should do is start from the second position both in the rows and in the columns, and stake out the sums Mx and My, and done!
for i = 2:rows-1
for j = 2:columns-1
1 comentario
Image Analyst
el 27 de Dic. de 2020
His original indexing code would have had no problem - it never went outside the image. Though most people would have done it like you did. The real problem (and what threw the error) was that he did this:
edg = edgy(cc);
without ever having written edgy function and either saving that in a file on the path (like the current folder), or having it defined down below in his script. You can't call a function if it's not defined and it has to be defined either
- in the same script, with the "function" keyword down below the script part of the file, OR
- in a separate m-file.
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