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

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sheno39 2013-9-11

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采纳的回答： Jan

assign zero value to pixel

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Answer 1

Jan 2013-9-11

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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 2013-9-11

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 2013-9-12

编辑：Jan 2013-9-12

This is a completely new question. Please ask it in a new thread.

"for n in all pixels less than 3 " is not clear to me. What is "f"?

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Answer 2

sidra 2013-9-11

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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 2013-9-11

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 2013-9-11

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% 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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Answer 3

Image Analyst 2013-9-11

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Yet another way

grayImage = zeros(size(grayImage), 'uint8');

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sheno39 2013-9-11

编辑：sheno39 2013-9-11

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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