what is the meaning of the following code ?

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Following code is for retrieving image from stego image in image steganography. Can anyone please tell me meaning of it ?
function Retrive_Callback(hObject, eventdata, handles)
global l;
h=mod(l,2);
p=zeros(1000,1000);
for x=1:1000
for y=1:1000
if(h(x,y)==1)
p(x,y)=255;
end
end
end
s=im2bw(p);
axes(handles.axes4);
imshow(s);
grid on;

Accepted Answer

Sebastian Körner
Sebastian Körner on 18 Sep 2019
the code semes to have some errors in it but i think the idea of your code is :
create a 1000x1000 matrix with zeros, replacing some zeros with 255 (all values in a line from top left corner to bottom right corner of the matrix)
format the matrix to a image and show the image
  1 Comment
Gayatri B
Gayatri B on 18 Sep 2019
Ohk, I'll check for errors. Thank You !

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More Answers (1)

Image Analyst
Image Analyst on 2 Oct 2019
p is just 255 * h. And s just thresholds p back to 0 or 1, which is just the original h. So all that code is unnecessary.
Replace with
function Retrive_Callback(hObject, eventdata, handles)
global l;
h=mod(l,2);
axes(handles.axes4);
imshow(h, []);
grid on;
By the way, you reversed x and y. Matrices are indexed (y, x) NOT (x,y) because the first index is the y, or row, value, not the column value.

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