# how to assign zero value to all pixels in an image ?

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sheno39 il 11 Set 2013
assign zero value to pixel
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### Risposta accettata

Jan il 11 Set 2013
It depends on what an "image" is. Please post more details in future questions. Fortunately the procedure to set the values to 1 is equal:
Img = rand(1024, 768, 3); % RGB image
Img(:) = 0;
Img2 = randi([0, 255], 1024, 768, 'uint8');
Img2(:) = 0;
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sheno39 il 11 Set 2013
thanks a lot. as am beginner in matlab programming, i do not how to do the code.. i need the code for following function: function computedensity() for x in all pixels p[x] = 0; for n in all pixels less than 3 p[x]+=exp(-(f[x]-f[n])^2
Jan il 12 Set 2013
Modificato: Jan il 12 Set 2013
"for n in all pixels less than 3 " is not clear to me. What is "f"?

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### Più risposte (2)

sidra il 11 Set 2013
I don't understand what purpose setting all the pixel values to zero would achieve.
Nevertheless One of the method is:
You can use two for loops starting from 1 to you image size and the within these loops set the pixel values to zero. Something of this sort
for i=1:n
for j=1:m
img(i,j)=0;
end
end
where n and m are the number of rows and columns respectively.
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sheno39 il 11 Set 2013
thanks for your answer.. how to code the following.. kindly reply.. function computedensity() for x in all pixels p[x] = 0; for n in all pixels less than 3 p[x]+=exp(-(f[x]-f[n])^2
Image Analyst il 11 Set 2013
% Find all pixels < 3
binaryImage = f < 3; % binaryImage is what you called x
Now, what's f(n)? What is n? In f(x), x is all pixels less than 3. But what is n in f(n)?

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Image Analyst il 11 Set 2013
Yet another way
grayImage = zeros(size(grayImage), 'uint8');
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sheno39 il 11 Set 2013
Modificato: sheno39 il 11 Set 2013
thanks for your help.. can u help me to code the following.. kindly reply.. function computedensity() for x in all pixels p[x] = 0; for n in all pixels less than 3 p[x]+=exp(-(f[x]-f[n])^2

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